Peronospora Black & White Stock Photos
RM2AR9D2T–damage, higher plants, fungi, peronospora viticola Date: undated Keywords: higher plants, damage, fungi Personal name: peronospora viticola
RMPG43C7–. Comparative morphology and biology of the fungi, mycetozoa and bacteria . Plant morphology; Fungi; Myxomycetes; Bacteriology. iia DIVISION I.—GENERAL MORPHOLOOr. A more noteworthy special case which recalls the formation of swarm-spores is that of the germination of the acrogenously formed spores (gonidia) of the plasmato- parous Peronosporeae (Peronospora densa, Rab. and P. pygmaea, Unger); here when a spore is placed in water the whole of the protoplasm suddenly swells and issues from the papilla-like tip of the spore which opens to admit its passage, and assumes the form of a spherical bo
RMRDWGA0–. Elementary botany. Botany. Fig- i37. Branching hypha of Peronospora alsinearum. Fig. 138. Branched hypha of downy mildew of grape showing peculiar branching (Plasmopara viticola).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Atkinson, George Francis, 1854-1918. New York, H. Holt
![. Plant studies; an elementary botany. Botany. Fig. 'SA'.. a hrancti of Peronospora in contact with two cells of a host ])lant, and sending into them its large hanstoria.—After DeBakt.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Coulter, John Merle, 1851-1928. New York, D. Appleton and Company Stock Photo](https://c8.alamy.com/comp/PG3D37/plant-studies-an-elementary-botany-botany-fig-sa-a-hrancti-of-peronospora-in-contact-with-two-cells-of-a-host-lant-and-sending-into-them-its-large-hanstoriaafter-debakt-please-note-that-these-images-are-extracted-from-scanned-page-images-that-may-have-been-digitally-enhanced-for-readability-coloration-and-appearance-of-these-illustrations-may-not-perfectly-resemble-the-original-work-coulter-john-merle-1851-1928-new-york-d-appleton-and-company-PG3D37.jpg ". Plant studies; an elementary botany. Botany. Fig. 'SA'.. a hrancti of Peronospora in contact with two cells of a host ])lant, and sending into them its large hanstoria.—After DeBakt.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Coulter, John Merle, 1851-1928. New York, D. Appleton and Company Stock Photo")
RMPG3D37–. Plant studies; an elementary botany. Botany. Fig. 'SA'.. a hrancti of Peronospora in contact with two cells of a host ])lant, and sending into them its large hanstoria.—After DeBakt.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Coulter, John Merle, 1851-1928. New York, D. Appleton and Company
RMRE0P8P–. Elementary botany. Botany. Fig. 137. Branching hypha of Peronospora alsinearum. Fig. 138. Branched hypha of downy mildew of grape shov.'ing peculiar branching (Plasmopara viticola).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Atkinson, George Francis, 1854-1918. New York, H. Holt
RMPG4DFX–. Comparative morphology and biology of the fungi, mycetozoa and bacteria . Plant morphology; Fungi; Myxomycetes; Bacteriology. 72 DIVISION I.—GENERAL MORPHOLOGY. one belonging to the sixth youngest spore in the chain. Phenomena essentially the same occur in other species of the Uredineae, but with considerable variations in form in the different species'. Where filiform sporophores rise free into the air, a further mechanical arrange- ment is found which greatly assists the shedding and scattering of the abscised spores. It may be readily observed in the Hyphomycetes, in Peronospora, for exam
RMRE1GHY–. Fungi; their nature, influence, and uses;. Fungi. 130 FUNGI. tbose whicli influence the dispersion of the minute sporidia from the terminal cysts. Probably they are more perennial in their character, and are assimilated more to the oogonia of Cystopus and Peronospora, being rather of the nature of resting spores, inasmuch as the same threads usually bear the terminal fruits. Thecaspokes is a term which may be applied generally to all sporidia produced in asci, but these are in turn so innumerable and variable that it will be necessary to treat of some of the groups individually. The Thecaspo
RMPG4ENN–. Diseases of economic plants . Plant diseases. 218 DISEASES OF ECONOMIC PLANTS promising resistant variety has been reported by Blinn.* Spraying as recommended for cucurbs is effective. Downy mildew (Peronospora cubensis B. & C). — This disease is described under cucumber. It is widespread and constitutes one of the most serious cantaloupe diseases.. Fig. 99. — Cantaloupe showing complete death of vines attacked by leaf blight. After Blinn. Wilt, fusariose (Fusarium vasinfedum Atk. var. nivea E. F. Smith).— Under watermelon this wilt is sufficiently discussed. It is not nearly so frequent
RMRE1GG6–. Fungi; their nature, influence, and uses;. Fungi. GERMINATION AND GEOWTH. 151. â Pseudospore of UsHlago recep- Ustilago as have been remarked in the sporules of the first generation in Tilletia. Returning to Ci/stopus, as the last of the Uredines, we must briefly recapitulate the observations made by Professor de Bary,* â who, by the bye, claims for them an affinity with Peronospora (Mncedines but too well known in connection with the potato disease), and not with the Ure- dines and their allies. In this genus there are two kinds of reproductive organs, those pro- duced on the surface of the
RMPG3YY3–. Fungous diseases of plants : with chapters on physiology, culture methods and technique . Fungi in agriculture. PHYCOMYCETES 163 an acute stage. Older onions are apparently more susceptible than young, and recovery in the former case is seldom. The fungus. The mycelium is considerable, and it penetrates practically all parts of the leaf. The minute haustoria are numerous,. Fig. 57. Onion Mildew (Photograph by H. H. Whetzel) Fig. 58. Mature Conidiophore, Germinat- ing CONIDIUM, AND MYCELIUM OF ONION Peronospora. (c after Whetzel) thread-like, and often branched at the tip. The conidiophores a
RMRDXT8M–. A manual of poisonous plants, chiefly of eastern North America, with brief notes on economic and medicinal plants, and numerous illustrations. Poisonous plants. 206 MANUAL OF POISONOUS PLANTS side of the oogonium; the antheridium. This pierces the oogonium and the protoplasm of the antheridium passes into the oosphere. In the species that have been studied like Peronospora parasitica, and Al- bugo Candida, the oosphere or egg cell contains a single nucleus, situated about at the center, the remaining nuclei having passed into the peripheral layer of the protoplasm of the periplasm. A single
RMPG43T3–. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. 52 DISEASES OF CROPS. 22) is examined beneath the microscope,i t^g mycelium of the fungus will be seen ramifying among the cells of the leaf. Wherever the mycelium comes in contact with the cells of the host-plant, they become discoloured. This is. Fig. 22.—Potato FnNous (Peronospora infestans). A to B. Transverse section of potato leaf, showing my celiom (spawn) of fungnp. A. Lower surface Witt two stomata (C) and eonidiophores passing through them. D. Conidium (spore). E. Zoo
RMRE1GG5–. Fungi; their nature, influence, and uses;. Fungi. â Pseudospore of UsHlago recep- Ustilago as have been remarked in the sporules of the first generation in Tilletia. Returning to Ci/stopus, as the last of the Uredines, we must briefly recapitulate the observations made by Professor de Bary,* â who, by the bye, claims for them an affinity with Peronospora (Mncedines but too well known in connection with the potato disease), and not with the Ure- dines and their allies. In this genus there are two kinds of reproductive organs, those pro- duced on the surface of the plant bursting through the c
RMPG42WD–. Diseases of plants induced by cryptogamic parasites : introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae . Plant diseases; Parasitic plants; Fungi. 134 PHYCOMYCETES. and branched conidiophores with light-brown conidia arise from their underside. Numerous oospores may be found in the leaves. Kirchner ^ observed the disease on leaves of four-year-old plants, yet without injurious effects. The follovnng are other British or American species: Peronospora ficariae, Tul. On Ranunculus, Myosunis, etc. P. corydalis, De By. On Corydalis and Dicentra. P. violae, De By. O
RMRPXP4B–. Text-book of botany, morphological and physiological. Botany. 2?6 THALLOPHYTES. (C. candidus), or the terminal conidium of each chain gives rise to a germinating filament, if it is capable of germinating, while the other cells of the conidial chain produce zoogonidia (C. Portulaca;). After the swarming is finished the zoogonidia become firmly attached to the cuticle of the host, invest themselves with a thin cell-wall, and, in the case of Peronospora infestans, put out a delicate germinating filament directly into an epidermal cell, piercing through its outer wall. After it has entered the c
![. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. MISCELLANEOUS CROPS. 157 The larvsB of this moth (already described) feed on the roots of lettuces. The Lettuce Mildew {Peronospora ganglioniformis, Fig. 51) produces pallid patches on lettuce leaves, and " in bad cases summer lettuces are quickly reduced to pu- trescent masses." The conidiophores of this fungus are. Fig. 51.—Lettuce Mildew [Peronospora ganglioniformis). A. A conidiophore and conidia. B. Oospores (reeting-spores). X 195 diam. (Zeiss's C. and 3 CO.). f Stock Photo](https://c8.alamy.com/comp/PG43KR/the-diseases-of-crops-and-their-remedies-a-handbook-of-economic-biology-for-farmers-and-students-plant-diseases-miscellaneous-crops-157-the-larvsb-of-this-moth-already-described-feed-on-the-roots-of-lettuces-the-lettuce-mildew-peronospora-ganglioniformis-fig-51-produces-pallid-patches-on-lettuce-leaves-and-quot-in-bad-cases-summer-lettuces-are-quickly-reduced-to-pu-trescent-massesquot-the-conidiophores-of-this-fungus-are-fig-51lettuce-mildew-peronospora-ganglioniformis-a-a-conidiophore-and-conidia-b-oospores-reeting-spores-x-195-diam-zeisss-c-and-3-co-f-PG43KR.jpg ". The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. MISCELLANEOUS CROPS. 157 The larvsB of this moth (already described) feed on the roots of lettuces. The Lettuce Mildew {Peronospora ganglioniformis, Fig. 51) produces pallid patches on lettuce leaves, and " in bad cases summer lettuces are quickly reduced to pu- trescent masses." The conidiophores of this fungus are. Fig. 51.—Lettuce Mildew [Peronospora ganglioniformis). A. A conidiophore and conidia. B. Oospores (reeting-spores). X 195 diam. (Zeiss's C. and 3 CO.). f Stock Photo")
RMPG43KR–. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. MISCELLANEOUS CROPS. 157 The larvsB of this moth (already described) feed on the roots of lettuces. The Lettuce Mildew {Peronospora ganglioniformis, Fig. 51) produces pallid patches on lettuce leaves, and " in bad cases summer lettuces are quickly reduced to pu- trescent masses." The conidiophores of this fungus are. Fig. 51.—Lettuce Mildew [Peronospora ganglioniformis). A. A conidiophore and conidia. B. Oospores (reeting-spores). X 195 diam. (Zeiss's C. and 3 CO.). f
RMRDD1MG–. Comparative morphology and biology of the fungi, mycetozoa and bacteria . Plant morphology; Fungi; Myxomycetes; Bacteriology. iia DIVISION I.—GENERAL MORPHOLOOr. A more noteworthy special case which recalls the formation of swarm-spores is that of the germination of the acrogenously formed spores (gonidia) of the plasmato- parous Peronosporeae (Peronospora densa, Rab. and P. pygmaea, Unger); here when a spore is placed in water the whole of the protoplasm suddenly swells and issues from the papilla-like tip of the spore which opens to admit its passage, and assumes the form of a spherical bo
RMPG0RG4–. Fungoid and insect pests of the farm. Agricultural pests. 34 Potato Disease and Allied Diseases [ch. disease from one season to another. The fungus does not attack the bulbs but prevents the leaves from carrying on their normal functions of manufacturing food stuff and so the bulbs are smaller.. Fig. 11. Conidiophore and conidia of Peronospora schUideni which causee onion mildew. (Magnified.) (After Massee.) Remedial Measures. Well-drained land does not suffer so much as wet land. Onions should not be planted on land which had a diseased crop of onions in the previous season.. Please note th
RMRDXNPK–. Botany of the living plant. Botany. Fio. 357. Fertilisation of thie Peronosporeae. I. Peronospora parasitica, young multi- nucleate oogonium {og), and antheridium {an). 2. Albtigo Candida. Oogonium witli the central, uni-nucleate egg {os), and the fertiUsing tube (a) of the antheridium which introduces the male nucleus. 3. The same. The fertilised egg (0) surrounded by periplasm ip). (After Wager, x 6G6.) {From Strasburger.) such an antheridium as is seen in Vaitcheria into the polHnodium of the Peronosporeae, is acomparativelyshght one: the latter does not hberate. I'lo. 358. MonobtepJiaris
![. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. ROOT CROPS. 47 and sand to be put on the ground before sowing the seeds. The odour of the tar is so offensive to insects that they cannot endure soil impregnated with it. (2) Burn all in- fested leaves. Cure.âDressing the land with gas-lime, soot, and lime, destroys the piipse of this pest. The Parsnip Fly {Psila rosce) has already been described in this chapter (see " Carrot Ply ").. Fig. 19.âMildew of Paesnips {Peronospora nivea). A. A spotted parsnip. B. Conidiopho Stock Photo](https://c8.alamy.com/comp/PG43TB/the-diseases-of-crops-and-their-remedies-a-handbook-of-economic-biology-for-farmers-and-students-plant-diseases-root-crops-47-and-sand-to-be-put-on-the-ground-before-sowing-the-seeds-the-odour-of-the-tar-is-so-offensive-to-insects-that-they-cannot-endure-soil-impregnated-with-it-2-burn-all-in-fested-leaves-curedressing-the-land-with-gas-lime-soot-and-lime-destroys-the-piipse-of-this-pest-the-parsnip-fly-psila-rosce-has-already-been-described-in-this-chapter-see-quot-carrot-ply-quot-fig-19mildew-of-paesnips-peronospora-nivea-a-a-spotted-parsnip-b-conidiopho-PG43TB.jpg ". The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. ROOT CROPS. 47 and sand to be put on the ground before sowing the seeds. The odour of the tar is so offensive to insects that they cannot endure soil impregnated with it. (2) Burn all in- fested leaves. Cure.âDressing the land with gas-lime, soot, and lime, destroys the piipse of this pest. The Parsnip Fly {Psila rosce) has already been described in this chapter (see " Carrot Ply ").. Fig. 19.âMildew of Paesnips {Peronospora nivea). A. A spotted parsnip. B. Conidiopho Stock Photo")
RMPG43TB–. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. ROOT CROPS. 47 and sand to be put on the ground before sowing the seeds. The odour of the tar is so offensive to insects that they cannot endure soil impregnated with it. (2) Burn all in- fested leaves. Cure.âDressing the land with gas-lime, soot, and lime, destroys the piipse of this pest. The Parsnip Fly {Psila rosce) has already been described in this chapter (see " Carrot Ply ").. Fig. 19.âMildew of Paesnips {Peronospora nivea). A. A spotted parsnip. B. Conidiopho
RMRDD1TY–. Comparative morphology and biology of the fungi, mycetozoa and bacteria . Plant morphology; Fungi; Myxomycetes; Bacteriology. 72 DIVISION I.—GENERAL MORPHOLOGY. one belonging to the sixth youngest spore in the chain. Phenomena essentially the same occur in other species of the Uredineae, but with considerable variations in form in the different species'. Where filiform sporophores rise free into the air, a further mechanical arrange- ment is found which greatly assists the shedding and scattering of the abscised spores. It may be readily observed in the Hyphomycetes, in Peronospora, for exam
![. The fungi which cause plant disease . Plant diseases; Fungi. THE FUNGI WHICH CAUSE PLANT DISEASE 95 them the pumpkin, squash, cucumber, muskmelon, watermelon, gourd, in fact according to the work of Selby '"^ any cucurbit ap- pears hable to attack. Clinton infected muskmelons with spores produced on cucumber. The fungus is especially prevalent on cucumbers raised under glass. Bremia Regel (p. 84) As in Peronospora except that just below the ends of the conidio- phore branches there are pronounced swellings from which spring radially a number of short branches each bearing an ovate, papi Stock Photo](https://c8.alamy.com/comp/PG4GY5/the-fungi-which-cause-plant-disease-plant-diseases-fungi-the-fungi-which-cause-plant-disease-95-them-the-pumpkin-squash-cucumber-muskmelon-watermelon-gourd-in-fact-according-to-the-work-of-selby-quot-any-cucurbit-ap-pears-hable-to-attack-clinton-infected-muskmelons-with-spores-produced-on-cucumber-the-fungus-is-especially-prevalent-on-cucumbers-raised-under-glass-bremia-regel-p-84-as-in-peronospora-except-that-just-below-the-ends-of-the-conidio-phore-branches-there-are-pronounced-swellings-from-which-spring-radially-a-number-of-short-branches-each-bearing-an-ovate-papi-PG4GY5.jpg ". The fungi which cause plant disease . Plant diseases; Fungi. THE FUNGI WHICH CAUSE PLANT DISEASE 95 them the pumpkin, squash, cucumber, muskmelon, watermelon, gourd, in fact according to the work of Selby '"^ any cucurbit ap- pears hable to attack. Clinton infected muskmelons with spores produced on cucumber. The fungus is especially prevalent on cucumbers raised under glass. Bremia Regel (p. 84) As in Peronospora except that just below the ends of the conidio- phore branches there are pronounced swellings from which spring radially a number of short branches each bearing an ovate, papi Stock Photo")
RMPG4GY5–. The fungi which cause plant disease . Plant diseases; Fungi. THE FUNGI WHICH CAUSE PLANT DISEASE 95 them the pumpkin, squash, cucumber, muskmelon, watermelon, gourd, in fact according to the work of Selby '"^ any cucurbit ap- pears hable to attack. Clinton infected muskmelons with spores produced on cucumber. The fungus is especially prevalent on cucumbers raised under glass. Bremia Regel (p. 84) As in Peronospora except that just below the ends of the conidio- phore branches there are pronounced swellings from which spring radially a number of short branches each bearing an ovate, papi
RMRDYG2W–. A textbook of botany for colleges and universities ... Botany. THALLOPHYTES 67 of zoospores, a feature which distinguishes the genus from Peronospora, under which the grape mildew was placed formerly. In the life history of Plasmo- para, therefore, zoospores, characteristic of Oomycetes, have been eliminated. This disease is of American origin and was unknown in Europe until American grape stocks were introduced as a protection against the destructive phylloxera. Peronospora. — These forms are very common parasites on ordinary vegetables, as peiis, beans, spinach, etc., and differ from Plasm
![. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. MISCELLANEOUS CRQPS. 157 The larvsB of this moth (already described) feed on the roots of lettuces. The Lettuce Mildew {Peronospora ganglioniformis, Fig. 61) produces pallid patches on lettuce leaves, and " in bad cases summer lettuces are quickly reduced to pu- trescent masses." The conidiophores of this fungus are. Fig. 51.—Lettuob Mildew {Peronospora ganglioniformis). A. A oonidiophore and conidia. B. Oospores (resting-spores). X 195 diam. (Zeiss's C. and 3 oc). fl Stock Photo](https://c8.alamy.com/comp/PG4AKJ/the-diseases-of-crops-and-their-remedies-a-handbook-of-economic-biology-for-farmers-and-students-plant-diseases-miscellaneous-crqps-157-the-larvsb-of-this-moth-already-described-feed-on-the-roots-of-lettuces-the-lettuce-mildew-peronospora-ganglioniformis-fig-61-produces-pallid-patches-on-lettuce-leaves-and-quot-in-bad-cases-summer-lettuces-are-quickly-reduced-to-pu-trescent-massesquot-the-conidiophores-of-this-fungus-are-fig-51lettuob-mildew-peronospora-ganglioniformis-a-a-oonidiophore-and-conidia-b-oospores-resting-spores-x-195-diam-zeisss-c-and-3-oc-fl-PG4AKJ.jpg ". The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. MISCELLANEOUS CRQPS. 157 The larvsB of this moth (already described) feed on the roots of lettuces. The Lettuce Mildew {Peronospora ganglioniformis, Fig. 61) produces pallid patches on lettuce leaves, and " in bad cases summer lettuces are quickly reduced to pu- trescent masses." The conidiophores of this fungus are. Fig. 51.—Lettuob Mildew {Peronospora ganglioniformis). A. A oonidiophore and conidia. B. Oospores (resting-spores). X 195 diam. (Zeiss's C. and 3 oc). fl Stock Photo")
RMPG4AKJ–. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. MISCELLANEOUS CRQPS. 157 The larvsB of this moth (already described) feed on the roots of lettuces. The Lettuce Mildew {Peronospora ganglioniformis, Fig. 61) produces pallid patches on lettuce leaves, and " in bad cases summer lettuces are quickly reduced to pu- trescent masses." The conidiophores of this fungus are. Fig. 51.—Lettuob Mildew {Peronospora ganglioniformis). A. A oonidiophore and conidia. B. Oospores (resting-spores). X 195 diam. (Zeiss's C. and 3 oc). fl
RMRE1JJK–. Plant studies; an elementary botany. Botany. JPt 'â Fig. 240. Peronospora, one of the Phycomycetes, ehowing at a an oogonium (o) con- taining an egg, and an antheridium (n) in contact; at o the antheridial tube pene- trating the oogonium and discharging the contents of the antheridium into the egg; at c the oogonium containing the oospore or resting spore.âAfter DeBaet.. In certain conditions special branches arise from the mycelium, which organize antheridia and oogonia, and remain within the host (Fig. 240). The oogonium is of the usual spherical form, organizing a single egg. The an-. Ple
RMPG3RTH–. The essentials of botany. Botany. 140 BOTANY. fungus which protrude through the epidermis of the host. In the Mildews (species of Peronospora) these branches. Fig. 66.âShowing tips of two conidia-beaiing branches of Potato-mildew (Peronospora infestans). Highly magnified. find their way through the breathing-pores, and bear their spores singly upon lateral branchlets (Fig. 66); in the White Rusts (species of Cystopus) the conidia-bearing branches collect under the epidermis and rupture it. Here the coni- dia are borne in chains or bead-like rows (Fig. 67). 292. In some species the conidia ge
![. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. 52 DISEASES OF CROPS. 22) is examined beneath the microscope,^ the mycelium of the fungus will be seen ramifying among the cells of the leaf. "Wherever the mycelium comes in contact with the cells of the host-plant, they become discoloured. This is. Fig. 22.^PoTATO FcNans {Peronospora infestans). A to B. Transverse section of potato leaf, showing mycelium (spawn) of fungup. A. Lower surface with two stomata (C) and conidiophores passing tiirough them. D. Conidium (spore). Stock Photo](https://c8.alamy.com/comp/RDGX69/the-diseases-of-crops-and-their-remedies-a-handbook-of-economic-biology-for-farmers-and-students-plant-diseases-52-diseases-of-crops-22-is-examined-beneath-the-microscope-the-mycelium-of-the-fungus-will-be-seen-ramifying-among-the-cells-of-the-leaf-quotwherever-the-mycelium-comes-in-contact-with-the-cells-of-the-host-plant-they-become-discoloured-this-is-fig-22potato-fcnans-peronospora-infestans-a-to-b-transverse-section-of-potato-leaf-showing-mycelium-spawn-of-fungup-a-lower-surface-with-two-stomata-c-and-conidiophores-passing-tiirough-them-d-conidium-spore-RDGX69.jpg ". The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. 52 DISEASES OF CROPS. 22) is examined beneath the microscope,^ the mycelium of the fungus will be seen ramifying among the cells of the leaf. "Wherever the mycelium comes in contact with the cells of the host-plant, they become discoloured. This is. Fig. 22.^PoTATO FcNans {Peronospora infestans). A to B. Transverse section of potato leaf, showing mycelium (spawn) of fungup. A. Lower surface with two stomata (C) and conidiophores passing tiirough them. D. Conidium (spore). Stock Photo")
RMRDGX69–. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. 52 DISEASES OF CROPS. 22) is examined beneath the microscope,^ the mycelium of the fungus will be seen ramifying among the cells of the leaf. "Wherever the mycelium comes in contact with the cells of the host-plant, they become discoloured. This is. Fig. 22.^PoTATO FcNans {Peronospora infestans). A to B. Transverse section of potato leaf, showing mycelium (spawn) of fungup. A. Lower surface with two stomata (C) and conidiophores passing tiirough them. D. Conidium (spore).
RMPG42WK–. Diseases of plants induced by cryptogamic parasites : introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae . Plant diseases; Parasitic plants; Fungi. PERONOSPORA. 133 oospore-coat (oospores of P. viciae have a coat with a regular net- work). It occurs on stems, leaves, and petioles of clovers, lucerne and other Papilionaceae, often with disastrous effect. P. sparsa, Berk. (Britain and U.S. America). This parasite on the rose was first observed in England. It injures indoor roses, causing a fall of the leaf, preceded by the appearance of lilac-coloured spots which
![. Grasses of North America [microform] : chapters on the physiology, composition, selection, improving and cultivation of grasses, management of grass lands, also chapters on clovers, injurious insects and fungi. Grasses; Forage plants; Graminées; Plantes fourragères. 480 CLOVER PERONOSPORA. SEEDLING ROT. 13. Clover poronospora, {Peronospora irifoUorum, DeBary). A dirty white or purple-brown mold, often completely covering the lower surface of the leaves of clover, alfalfa, none-such, etc. (See Fig. 175.) The life history of this species is quite similar to that of the last, though they differ Stock Photo](https://c8.alamy.com/comp/RJ6M1G/grasses-of-north-america-microform-chapters-on-the-physiology-composition-selection-improving-and-cultivation-of-grasses-management-of-grass-lands-also-chapters-on-clovers-injurious-insects-and-fungi-grasses-forage-plants-gramines-plantes-fourragres-480-clover-peronospora-seedling-rot-13-clover-poronospora-peronospora-irifouorum-debary-a-dirty-white-or-purple-brown-mold-often-completely-covering-the-lower-surface-of-the-leaves-of-clover-alfalfa-none-such-etc-see-fig-175-the-life-history-of-this-species-is-quite-similar-to-that-of-the-last-though-they-differ-RJ6M1G.jpg ". Grasses of North America [microform] : chapters on the physiology, composition, selection, improving and cultivation of grasses, management of grass lands, also chapters on clovers, injurious insects and fungi. Grasses; Forage plants; Graminées; Plantes fourragères. 480 CLOVER PERONOSPORA. SEEDLING ROT. 13. Clover poronospora, {Peronospora irifoUorum, DeBary). A dirty white or purple-brown mold, often completely covering the lower surface of the leaves of clover, alfalfa, none-such, etc. (See Fig. 175.) The life history of this species is quite similar to that of the last, though they differ Stock Photo")
RMRJ6M1G–. Grasses of North America [microform] : chapters on the physiology, composition, selection, improving and cultivation of grasses, management of grass lands, also chapters on clovers, injurious insects and fungi. Grasses; Forage plants; Graminées; Plantes fourragères. 480 CLOVER PERONOSPORA. SEEDLING ROT. 13. Clover poronospora, {Peronospora irifoUorum, DeBary). A dirty white or purple-brown mold, often completely covering the lower surface of the leaves of clover, alfalfa, none-such, etc. (See Fig. 175.) The life history of this species is quite similar to that of the last, though they differ
RMPG43TC–. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. ROOT CROPS. 43 reduce its vitality considerably. When artificial cultures were exposed to a temperature of —17° C. for one day, the organisms were completely destroyed. An E.M.F.i of 3'3 volts (at 17° C.) destroyed B. allii when growing in sterilized pork broth (neutral). Prevention.—Onions, lohen stored, should be kept in a. Fig. 17.— Onion Mildew (Peronospora ScUeideniana). A. The fuBgDS growing from the base of an onion leaf. B. Mycelium ramifying amongst the cells of the ho
RMRE0C83–. Experimental morphology. Protoplasm; Growth. 420 EFFECT OF LIGHT [Ch. xvn observers in the early half of the century, and, more recently, NoBBE ('82), Adrianowsky ('83), and others, have shown that germination of seeds takes place slightly earlier in the dark than in daylight. Among fungi, also, we have the assur- ances of Hoffmann ('60, p. 321) that the spores of the mush- room Agaricus campestris germinate more slowly in the light; and of DE Baey ('63, p. 40) that the spores of the potato fungus, Peronospora infestans, and its allies do germinate with difficulty in the daylight, and not at
RMPG3RTA–. The essentials of botany. Botany. Fig. 66.âShowing tips of two conidia-beaiing branches of Potato-mildew (Peronospora infestans). Highly magnified. find their way through the breathing-pores, and bear their spores singly upon lateral branchlets (Fig. 66); in the White Rusts (species of Cystopus) the conidia-bearing branches collect under the epidermis and rupture it. Here the coni- dia are borne in chains or bead-like rows (Fig. 67). 292. In some species the conidia germi- nate by forming a tube; in others they divide internally and finally emit many zoospores. The latter eventually protrude
RMRE0NJG–. The elements of botany embracing organography, histology, vegetable physiology, systematic botany and economic botany ... together with a complete glossary of botanical terms. Botany. OOSPORES. 135 ferce, as white, blister-like patches, the conldia are produced just beneath the epidermis, which becomes ruptured, and allows their escape. In Peronospora, as the Grape-Mildew (P. vHicola), the Potato Fungus (P. infestans), the white, frost-like down on Peppergrass (P. paradtioa), etc., the conidia are produced on aerial branches of the hyphse growing from the stomates (Fig. 250). The conidia qui
RMPG4H0K–. The fungi which cause plant disease . Plant diseases; Fungi. 84 THE FUNGI WHICH CAUSE PLANT DISEASE timate branchlets arise radially; germ tube produced from the apex of the conidia 7. Bremia, p. 95. Conidiophores without subapical en- largements; conidia germinating from the side 8. Peronospora, p. 95. Phytophthora de Bary (p. 83) This genus is of especial interest on account of its one exceed- ingly destructive representative, P. infestans, which occupies an historic position in phytopathology as one of the earliest of para- sitic fungi to receive study in any way complete or adequate; stu
RMRE1GKK–. Fungi; their nature, influence, and uses;. Fungi. 74 FUNGI.. 40.—Rlwpalomijciiii caiididus. dom are spores and threads colourless or of bright tints. In the Mucedines, on the contrary, the threads are never coated, seldom dingy, mostly white or of pure colours, and the spores have less a tendency to extra development or multiplex septa- tion. In some genera, as in Peronospora for instance,* a secondary fruit is produced in the form of resting spores from the mycelium; and these generate zoospores as well as the primary spores, similar to those common in AlgcB. This latter genus is very de- s
RMPFYEK3–. A text-book of botany for secondary schools. Botany. FUNGI 145 as apple, pear, cherry, rose, hop, grape, wheat, gooseberry, cucumber, pea, verbena, sunflower, aster, etc. In fact, very few seed-plants seem to escape their attacks. Being exter- nal parasites, mildews are not necessarily destructive; but they often cause the death of the host. An examination of the my- celium shows that its filaments have partition walls; and hence the body is not ccenocytic, as in Mucor and Peronospora, but made up of a row of cells as in the Conferva forms among the green Algae. Small disk-like outgrowths ar
RMRDJFJM–. Fungous diseases of plants : with chapters on physiology, culture methods and technique . Fungi in agriculture. PHYCOMYCETES 163 an acute stage. Older onions are apparently more susceptible than young, and recovery in the former case is seldom. The fungus. The mycelium is considerable, and it penetrates practically all parts of the leaf. The minute haustoria are numerous,. Fig. 57. Onion Mildew (Photograph by H. H. Whetzel) Fig. 58. Mature Conidiophore, Germinat- ing CONIDIUM, AND MYCELIUM OF ONION Peronospora. (c after Whetzel) thread-like, and often branched at the tip. The conidiophores a
![. Diseases of truck crops and their control . Vegetables. Fig. 54. Onion Diseases. a. Downy mildew, b. mature conidiophore and conidia of Peronospora sckleideni, c. fertilization of the female oogomum by the male antheridium, d. oospore (a. to d. after Wh^tzd), e. onion smut, /, spore ball of the smut fungus, g. spore germina- tion, formation of sporidia at x, h. Vermicularia anthracnose, i. section through acervulis of Vermicidaria cirdnans, j. setae and spore formation in V. circinansXe. to g., *. and j". after Thaxter), k. pink root of onion, healthy and diseased bulbs, I. pirJc root o Stock Photo](https://c8.alamy.com/comp/PG4CGC/diseases-of-truck-crops-and-their-control-vegetables-fig-54-onion-diseases-a-downy-mildew-b-mature-conidiophore-and-conidia-of-peronospora-sckleideni-c-fertilization-of-the-female-oogomum-by-the-male-antheridium-d-oospore-a-to-d-after-whtzd-e-onion-smut-spore-ball-of-the-smut-fungus-g-spore-germina-tion-formation-of-sporidia-at-x-h-vermicularia-anthracnose-i-section-through-acervulis-of-vermicidaria-cirdnans-j-setae-and-spore-formation-in-v-circinansxe-to-g-and-jquot-after-thaxter-k-pink-root-of-onion-healthy-and-diseased-bulbs-i-pirjc-root-o-PG4CGC.jpg ". Diseases of truck crops and their control . Vegetables. Fig. 54. Onion Diseases. a. Downy mildew, b. mature conidiophore and conidia of Peronospora sckleideni, c. fertilization of the female oogomum by the male antheridium, d. oospore (a. to d. after Wh^tzd), e. onion smut, /, spore ball of the smut fungus, g. spore germina- tion, formation of sporidia at x, h. Vermicularia anthracnose, i. section through acervulis of Vermicidaria cirdnans, j. setae and spore formation in V. circinansXe. to g., *. and j". after Thaxter), k. pink root of onion, healthy and diseased bulbs, I. pirJc root o Stock Photo")
RMPG4CGC–. Diseases of truck crops and their control . Vegetables. Fig. 54. Onion Diseases. a. Downy mildew, b. mature conidiophore and conidia of Peronospora sckleideni, c. fertilization of the female oogomum by the male antheridium, d. oospore (a. to d. after Wh^tzd), e. onion smut, /, spore ball of the smut fungus, g. spore germina- tion, formation of sporidia at x, h. Vermicularia anthracnose, i. section through acervulis of Vermicidaria cirdnans, j. setae and spore formation in V. circinansXe. to g., *. and j". after Thaxter), k. pink root of onion, healthy and diseased bulbs, I. pirJc root o
RMRE2M3N–. Elementary botany. Botany. CAMETOPIIYTE AND SPOROPHYTE. 329 nucleus with the egg nucleus it is called double jertilization. The sperm nucleus is usually smaller than the egg nucleus, but often grows to near or quite the size of the egg nucleus before union. See figs. 394 and 395. 657. Fertilization in plants is fundamentally the same as in animals.—In all the great groups of plants as represented by spirogyra, oedogonium, vaucheria, peronospora, ferns, gymno-. Fig. ,;92- Two- and four-celled Etage of embryo-sac of lilium. The middle one shows division of nuclei to form the four-celled stage.
RMPG4CTP–. Diseases of truck crops and their control . Vegetables. Fig. 20. Beet Diseases. fl. Crown gall, b. scab, c, downy mildew, d. Conidiophore of Peronospora schachtii arising from a stomate of an infected beet leaf, e. germinating zoospore of P. schach- tii,/. oospore of P. schachtii, g. Cercospora leaf spot (after Halsted), ft. conidiophore and conidia of Cercospora beticola (after Duggar), i, Phoma leaf spot (after Pool and McKay), k, pycnidium of Phoma beta (after T. Johnson) {d.-f. after PrilUeux).. Please note that these images are extracted from scanned page images that may have been digit
RMRDJ5CF–. Microbes, ferments and moulds . Bacteria; Fungi; Fermentation. PAEASITIO FUNGI AND MOULDS, 29 very small, and are foiined within a small enlargement (sporangmm) borne on a free hypha of the mycelium. Their succession is constant and numerous as long as the plant is in a favourable medium in which it can flourish. The spores which are found in the same medium germinate, and reproduce a mycelium similar to that from which they had their origin.. Fig. 16.—Reproductive organs of Peronospora calotheea (mncta magniSed). The oospores may be as much as a thousand times larger in volume than ordinary
![. Microbes, ferments and moulds . Bacteria; Fungi; Fermentation. 36 MICROBES, FERMENTS, AND MOULDS. oidium. Brown patches appear on the upper surface of the leaf, as if it had been scorched; and in corre- spondence with these there is a delicate down " like the whiteness of a slight hoar-frost" (Vaissier) on its lower surface. The hyphse issuing from the mycelium ramify at right angles, and these branches bear the spores, as in the potato-fungus, Peronospora infestans (Figs. 17,18). These numerous spores, diffused through the air, are powerful sources of contagion.. Fig. 17.—Mildew • Stock Photo](https://c8.alamy.com/comp/RDJ5C8/microbes-ferments-and-moulds-bacteria-fungi-fermentation-36-microbes-ferments-and-moulds-oidium-brown-patches-appear-on-the-upper-surface-of-the-leaf-as-if-it-had-been-scorched-and-in-corre-spondence-with-these-there-is-a-delicate-down-quot-like-the-whiteness-of-a-slight-hoar-frostquot-vaissier-on-its-lower-surface-the-hyphse-issuing-from-the-mycelium-ramify-at-right-angles-and-these-branches-bear-the-spores-as-in-the-potato-fungus-peronospora-infestans-figs-1718-these-numerous-spores-diffused-through-the-air-are-powerful-sources-of-contagion-fig-17mildew-RDJ5C8.jpg ". Microbes, ferments and moulds . Bacteria; Fungi; Fermentation. 36 MICROBES, FERMENTS, AND MOULDS. oidium. Brown patches appear on the upper surface of the leaf, as if it had been scorched; and in corre- spondence with these there is a delicate down " like the whiteness of a slight hoar-frost" (Vaissier) on its lower surface. The hyphse issuing from the mycelium ramify at right angles, and these branches bear the spores, as in the potato-fungus, Peronospora infestans (Figs. 17,18). These numerous spores, diffused through the air, are powerful sources of contagion.. Fig. 17.—Mildew • Stock Photo")
RMRDJ5C8–. Microbes, ferments and moulds . Bacteria; Fungi; Fermentation. 36 MICROBES, FERMENTS, AND MOULDS. oidium. Brown patches appear on the upper surface of the leaf, as if it had been scorched; and in corre- spondence with these there is a delicate down " like the whiteness of a slight hoar-frost" (Vaissier) on its lower surface. The hyphse issuing from the mycelium ramify at right angles, and these branches bear the spores, as in the potato-fungus, Peronospora infestans (Figs. 17,18). These numerous spores, diffused through the air, are powerful sources of contagion.. Fig. 17.—Mildew •
RMRDHT1J–. Microbes, ferments and moulds . Bacteria; Fungi; Fermentation. THE MICROBES OF HUMAN DISEASES. 203 FeiTan regards this peronospora as the infectious agent of cholera. Yet it seems extraordinary that such a remarkable polymorphism should have escaped the observation of Koch and of the numerous micro-. Figs. 88, 89, 90.—Evolution of cholera microbe {Pernnospora Ferrani: Feiran'); 1. ClioleTa microbe {Jiadllus komma discovered by Kocti. '2. Spiral form of bacillus, transferred from gelatine to an infusion. 3. Degeneration of spiral form after a series of successive cultures. 4. Cholera microbe
RMRDE37W–. Diseases of economic plants . Plant diseases. 218 DISEASES OF ECONOMIC PLANTS promising resistant variety has been reported by Blinn.* Spraying as recommended for cucurbs is effective. Downy mildew (Peronospora cubensis B. & C). — This disease is described under cucumber. It is widespread and constitutes one of the most serious cantaloupe diseases.. Fig. 99. — Cantaloupe showing complete death of vines attacked by leaf blight. After Blinn. Wilt, fusariose (Fusarium vasinfedum Atk. var. nivea E. F. Smith).— Under watermelon this wilt is sufficiently discussed. It is not nearly so frequent
RMRDC2HD–. Diseases of plants induced by cryptogamic parasites : introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae . Plant diseases; Parasitic plants; Fungi. 134 PHYCOMYCETES. and branched conidiophores with light-brown conidia arise from their underside. Numerous oospores may be found in the leaves. Kirchner ^ observed the disease on leaves of four-year-old plants, yet without injurious effects. The follovnng are other British or American species: Peronospora ficariae, Tul. On Ranunculus, Myosunis, etc. P. corydalis, De By. On Corydalis and Dicentra. P. violae, De By. O
![. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. MISCELLANEOUS CROPS. 157 The larvsB of this moth (already described) feed on the roots of lettuces. The Lettuce Mildew {Peronospora ganglioniformis, Fig. 51) produces pallid patches on lettuce leaves, and " in bad cases summer lettuces are quickly reduced to pu- trescent masses." The conidiophores of this fungus are. Fig. 51.—Lettuce Mildew [Peronospora ganglioniformis). A. A conidiophore and conidia. B. Oospores (reeting-spores). X 195 diam. (Zeiss's C. and 3 CO.). f Stock Photo](https://c8.alamy.com/comp/RDDY9B/the-diseases-of-crops-and-their-remedies-a-handbook-of-economic-biology-for-farmers-and-students-plant-diseases-miscellaneous-crops-157-the-larvsb-of-this-moth-already-described-feed-on-the-roots-of-lettuces-the-lettuce-mildew-peronospora-ganglioniformis-fig-51-produces-pallid-patches-on-lettuce-leaves-and-quot-in-bad-cases-summer-lettuces-are-quickly-reduced-to-pu-trescent-massesquot-the-conidiophores-of-this-fungus-are-fig-51lettuce-mildew-peronospora-ganglioniformis-a-a-conidiophore-and-conidia-b-oospores-reeting-spores-x-195-diam-zeisss-c-and-3-co-f-RDDY9B.jpg ". The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. MISCELLANEOUS CROPS. 157 The larvsB of this moth (already described) feed on the roots of lettuces. The Lettuce Mildew {Peronospora ganglioniformis, Fig. 51) produces pallid patches on lettuce leaves, and " in bad cases summer lettuces are quickly reduced to pu- trescent masses." The conidiophores of this fungus are. Fig. 51.—Lettuce Mildew [Peronospora ganglioniformis). A. A conidiophore and conidia. B. Oospores (reeting-spores). X 195 diam. (Zeiss's C. and 3 CO.). f Stock Photo")
RMRDDY9B–. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. MISCELLANEOUS CROPS. 157 The larvsB of this moth (already described) feed on the roots of lettuces. The Lettuce Mildew {Peronospora ganglioniformis, Fig. 51) produces pallid patches on lettuce leaves, and " in bad cases summer lettuces are quickly reduced to pu- trescent masses." The conidiophores of this fungus are. Fig. 51.—Lettuce Mildew [Peronospora ganglioniformis). A. A conidiophore and conidia. B. Oospores (reeting-spores). X 195 diam. (Zeiss's C. and 3 CO.). f
![. The fungi which cause plant disease . Plant diseases; Fungi. THE FUNGI WHICH CAUSE PLANT DISEASE 95 them the pumpkin, squash, cucumber, muskmelon, watermelon, gourd, in fact according to the work of Selby '"^ any cucurbit ap- pears hable to attack. Clinton infected muskmelons with spores produced on cucumber. The fungus is especially prevalent on cucumbers raised under glass. Bremia Regel (p. 84) As in Peronospora except that just below the ends of the conidio- phore branches there are pronounced swellings from which spring radially a number of short branches each bearing an ovate, papi Stock Photo](https://c8.alamy.com/comp/RDE6RT/the-fungi-which-cause-plant-disease-plant-diseases-fungi-the-fungi-which-cause-plant-disease-95-them-the-pumpkin-squash-cucumber-muskmelon-watermelon-gourd-in-fact-according-to-the-work-of-selby-quot-any-cucurbit-ap-pears-hable-to-attack-clinton-infected-muskmelons-with-spores-produced-on-cucumber-the-fungus-is-especially-prevalent-on-cucumbers-raised-under-glass-bremia-regel-p-84-as-in-peronospora-except-that-just-below-the-ends-of-the-conidio-phore-branches-there-are-pronounced-swellings-from-which-spring-radially-a-number-of-short-branches-each-bearing-an-ovate-papi-RDE6RT.jpg ". The fungi which cause plant disease . Plant diseases; Fungi. THE FUNGI WHICH CAUSE PLANT DISEASE 95 them the pumpkin, squash, cucumber, muskmelon, watermelon, gourd, in fact according to the work of Selby '"^ any cucurbit ap- pears hable to attack. Clinton infected muskmelons with spores produced on cucumber. The fungus is especially prevalent on cucumbers raised under glass. Bremia Regel (p. 84) As in Peronospora except that just below the ends of the conidio- phore branches there are pronounced swellings from which spring radially a number of short branches each bearing an ovate, papi Stock Photo")
RMRDE6RT–. The fungi which cause plant disease . Plant diseases; Fungi. THE FUNGI WHICH CAUSE PLANT DISEASE 95 them the pumpkin, squash, cucumber, muskmelon, watermelon, gourd, in fact according to the work of Selby '"^ any cucurbit ap- pears hable to attack. Clinton infected muskmelons with spores produced on cucumber. The fungus is especially prevalent on cucumbers raised under glass. Bremia Regel (p. 84) As in Peronospora except that just below the ends of the conidio- phore branches there are pronounced swellings from which spring radially a number of short branches each bearing an ovate, papi
RMRDDYHN–. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. 52 DISEASES OF CROPS. 22) is examined beneath the microscope,i t^g mycelium of the fungus will be seen ramifying among the cells of the leaf. Wherever the mycelium comes in contact with the cells of the host-plant, they become discoloured. This is. Fig. 22.—Potato FnNous (Peronospora infestans). A to B. Transverse section of potato leaf, showing my celiom (spawn) of fungnp. A. Lower surface Witt two stomata (C) and eonidiophores passing through them. D. Conidium (spore). E. Zoo
![. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. ROOT CROPS. 47 and sand to be put on the ground before sowing the seeds. The odour of the tar is so offensive to insects that they cannot endure soil impregnated with it. (2) Burn all in- fested leaves. Cure.âDressing the land with gas-lime, soot, and lime, destroys the piipse of this pest. The Parsnip Fly {Psila rosce) has already been described in this chapter (see " Carrot Ply ").. Fig. 19.âMildew of Paesnips {Peronospora nivea). A. A spotted parsnip. B. Conidiopho Stock Photo](https://c8.alamy.com/comp/RDDYHW/the-diseases-of-crops-and-their-remedies-a-handbook-of-economic-biology-for-farmers-and-students-plant-diseases-root-crops-47-and-sand-to-be-put-on-the-ground-before-sowing-the-seeds-the-odour-of-the-tar-is-so-offensive-to-insects-that-they-cannot-endure-soil-impregnated-with-it-2-burn-all-in-fested-leaves-curedressing-the-land-with-gas-lime-soot-and-lime-destroys-the-piipse-of-this-pest-the-parsnip-fly-psila-rosce-has-already-been-described-in-this-chapter-see-quot-carrot-ply-quot-fig-19mildew-of-paesnips-peronospora-nivea-a-a-spotted-parsnip-b-conidiopho-RDDYHW.jpg ". The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. ROOT CROPS. 47 and sand to be put on the ground before sowing the seeds. The odour of the tar is so offensive to insects that they cannot endure soil impregnated with it. (2) Burn all in- fested leaves. Cure.âDressing the land with gas-lime, soot, and lime, destroys the piipse of this pest. The Parsnip Fly {Psila rosce) has already been described in this chapter (see " Carrot Ply ").. Fig. 19.âMildew of Paesnips {Peronospora nivea). A. A spotted parsnip. B. Conidiopho Stock Photo")
RMRDDYHW–. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. ROOT CROPS. 47 and sand to be put on the ground before sowing the seeds. The odour of the tar is so offensive to insects that they cannot endure soil impregnated with it. (2) Burn all in- fested leaves. Cure.âDressing the land with gas-lime, soot, and lime, destroys the piipse of this pest. The Parsnip Fly {Psila rosce) has already been described in this chapter (see " Carrot Ply ").. Fig. 19.âMildew of Paesnips {Peronospora nivea). A. A spotted parsnip. B. Conidiopho
![. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. MISCELLANEOUS CRQPS. 157 The larvsB of this moth (already described) feed on the roots of lettuces. The Lettuce Mildew {Peronospora ganglioniformis, Fig. 61) produces pallid patches on lettuce leaves, and " in bad cases summer lettuces are quickly reduced to pu- trescent masses." The conidiophores of this fungus are. Fig. 51.—Lettuob Mildew {Peronospora ganglioniformis). A. A oonidiophore and conidia. B. Oospores (resting-spores). X 195 diam. (Zeiss's C. and 3 oc). fl Stock Photo](https://c8.alamy.com/comp/RDGX1D/the-diseases-of-crops-and-their-remedies-a-handbook-of-economic-biology-for-farmers-and-students-plant-diseases-miscellaneous-crqps-157-the-larvsb-of-this-moth-already-described-feed-on-the-roots-of-lettuces-the-lettuce-mildew-peronospora-ganglioniformis-fig-61-produces-pallid-patches-on-lettuce-leaves-and-quot-in-bad-cases-summer-lettuces-are-quickly-reduced-to-pu-trescent-massesquot-the-conidiophores-of-this-fungus-are-fig-51lettuob-mildew-peronospora-ganglioniformis-a-a-oonidiophore-and-conidia-b-oospores-resting-spores-x-195-diam-zeisss-c-and-3-oc-fl-RDGX1D.jpg ". The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. MISCELLANEOUS CRQPS. 157 The larvsB of this moth (already described) feed on the roots of lettuces. The Lettuce Mildew {Peronospora ganglioniformis, Fig. 61) produces pallid patches on lettuce leaves, and " in bad cases summer lettuces are quickly reduced to pu- trescent masses." The conidiophores of this fungus are. Fig. 51.—Lettuob Mildew {Peronospora ganglioniformis). A. A oonidiophore and conidia. B. Oospores (resting-spores). X 195 diam. (Zeiss's C. and 3 oc). fl Stock Photo")
RMRDGX1D–. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. MISCELLANEOUS CRQPS. 157 The larvsB of this moth (already described) feed on the roots of lettuces. The Lettuce Mildew {Peronospora ganglioniformis, Fig. 61) produces pallid patches on lettuce leaves, and " in bad cases summer lettuces are quickly reduced to pu- trescent masses." The conidiophores of this fungus are. Fig. 51.—Lettuob Mildew {Peronospora ganglioniformis). A. A oonidiophore and conidia. B. Oospores (resting-spores). X 195 diam. (Zeiss's C. and 3 oc). fl
![. Grasses of North America [microform] : chapters on the physiology, composition, selection, improving and cultivation of grasses, management of grass lands, also chapters on clovers, injurious insects and fungi. Grasses; Forage plants; Graminées; Plantes fourragères. THE GRASS PERNNOSPORA. 429 dense, spongy mass. Wire grass is subject to similar attacka from H. nodosum, (B. & C), and other species of the same genus occur on different grasses in a similar manner, PERONOSPOREAE. 13. (irass-peronospora. {Pero?iospora graminicola, Sacc.) In the leaves of Hungarian grass and pigeon grass, ulti Stock Photo](https://c8.alamy.com/comp/RJ6M1P/grasses-of-north-america-microform-chapters-on-the-physiology-composition-selection-improving-and-cultivation-of-grasses-management-of-grass-lands-also-chapters-on-clovers-injurious-insects-and-fungi-grasses-forage-plants-gramines-plantes-fourragres-the-grass-pernnospora-429-dense-spongy-mass-wire-grass-is-subject-to-similar-attacka-from-h-nodosum-b-amp-c-and-other-species-of-the-same-genus-occur-on-different-grasses-in-a-similar-manner-peronosporeae-13-irass-peronospora-peroiospora-graminicola-sacc-in-the-leaves-of-hungarian-grass-and-pigeon-grass-ulti-RJ6M1P.jpg ". Grasses of North America [microform] : chapters on the physiology, composition, selection, improving and cultivation of grasses, management of grass lands, also chapters on clovers, injurious insects and fungi. Grasses; Forage plants; Graminées; Plantes fourragères. THE GRASS PERNNOSPORA. 429 dense, spongy mass. Wire grass is subject to similar attacka from H. nodosum, (B. & C), and other species of the same genus occur on different grasses in a similar manner, PERONOSPOREAE. 13. (irass-peronospora. {Pero?iospora graminicola, Sacc.) In the leaves of Hungarian grass and pigeon grass, ulti Stock Photo")
RMRJ6M1P–. Grasses of North America [microform] : chapters on the physiology, composition, selection, improving and cultivation of grasses, management of grass lands, also chapters on clovers, injurious insects and fungi. Grasses; Forage plants; Graminées; Plantes fourragères. THE GRASS PERNNOSPORA. 429 dense, spongy mass. Wire grass is subject to similar attacka from H. nodosum, (B. & C), and other species of the same genus occur on different grasses in a similar manner, PERONOSPOREAE. 13. (irass-peronospora. {Pero?iospora graminicola, Sacc.) In the leaves of Hungarian grass and pigeon grass, ulti
RMRE1JJT–. Plant studies; an elementary botany. Botany. Fig. 239. A branch of Peronospora in contact with two celle of a host plant, and sending into them its large haustoria.âAfter DeBaey.. JPt 'â Fig. 240. Peronospora, one of the Phycomycetes, ehowing at a an oogonium (o) con- taining an egg, and an antheridium (n) in contact; at o the antheridial tube pene- trating the oogonium and discharging the contents of the antheridium into the egg; at c the oogonium containing the oospore or resting spore.âAfter DeBaet.. Please note that these images are extracted from scanned page images that may have been d
RMRDWBYB–. The essentials of botany. Botany. 140 ^OtAl^f. fungus which protrude through the epidermis of the liost. In the Mildews (species of Peronospora) these branches. Fio. 66.—Showing tips of two conidia-beaiing branches of Potato-mildew (Peronospora infestans). Highly magnified. find their way through the hreathing-pores, and bear their spores singly upon lateral branchlets (Fig. 66); in the White Rusts (species of Cystopus) the conidia-bearing branches collect under the epidermis and rupture it. Here the coni- dia are borne in chains or bead-like rows (Fig. 67). 292. In some species the conidia
RMRDXNRK–. Botany of the living plant. Botany. 422 BOTANY OF THE LIVING PLANT through the air. But it shows its real nature on germination by pro- ducing zoospores which are hberated in water. The modification of. Fio. 357. Fertilisation of thie Peronosporeae. I. Peronospora parasitica, young multi- nucleate oogonium {og), and antheridium {an). 2. Albtigo Candida. Oogonium witli the central, uni-nucleate egg {os), and the fertiUsing tube (a) of the antheridium which introduces the male nucleus. 3. The same. The fertilised egg (0) surrounded by periplasm ip). (After Wager, x 6G6.) {From Strasburger.) su
![. The Book of gardening; a handbook of horticulture. Gardening; Horticulture. ON VEGETABLE' CULTURE. 1065 methods suggested in the Chapter "On Pests Generally." A Mildew also asserts itself upon the leaves of Lettuce, both forced and grown outside, though chiefly upon the former. It is a species of Peronospora, and causes the plant to turn sickly and die. A well-ventilated house and a not too moist atmosphere will tend to keep it at bay. Mushrooms. These delicious vegetables, or fungi, are always appreciated, and when manure from horses fed on dry food can be obtained in quantity the Stock Photo](https://c8.alamy.com/comp/RDXD0Y/the-book-of-gardening-a-handbook-of-horticulture-gardening-horticulture-on-vegetable-culture-1065-methods-suggested-in-the-chapter-quoton-pests-generallyquot-a-mildew-also-asserts-itself-upon-the-leaves-of-lettuce-both-forced-and-grown-outside-though-chiefly-upon-the-former-it-is-a-species-of-peronospora-and-causes-the-plant-to-turn-sickly-and-die-a-well-ventilated-house-and-a-not-too-moist-atmosphere-will-tend-to-keep-it-at-bay-mushrooms-these-delicious-vegetables-or-fungi-are-always-appreciated-and-when-manure-from-horses-fed-on-dry-food-can-be-obtained-in-quantity-the-RDXD0Y.jpg ". The Book of gardening; a handbook of horticulture. Gardening; Horticulture. ON VEGETABLE' CULTURE. 1065 methods suggested in the Chapter "On Pests Generally." A Mildew also asserts itself upon the leaves of Lettuce, both forced and grown outside, though chiefly upon the former. It is a species of Peronospora, and causes the plant to turn sickly and die. A well-ventilated house and a not too moist atmosphere will tend to keep it at bay. Mushrooms. These delicious vegetables, or fungi, are always appreciated, and when manure from horses fed on dry food can be obtained in quantity the Stock Photo")
RMRDXD0Y–. The Book of gardening; a handbook of horticulture. Gardening; Horticulture. ON VEGETABLE' CULTURE. 1065 methods suggested in the Chapter "On Pests Generally." A Mildew also asserts itself upon the leaves of Lettuce, both forced and grown outside, though chiefly upon the former. It is a species of Peronospora, and causes the plant to turn sickly and die. A well-ventilated house and a not too moist atmosphere will tend to keep it at bay. Mushrooms. These delicious vegetables, or fungi, are always appreciated, and when manure from horses fed on dry food can be obtained in quantity the
RMRE0P86–. Elementary botany. Botany. *t .4.-. if ^. Fig. 143. Fertilization in Peronospora alsinearum; tube from antheridium carrying in the sperm nucleus in figure at the left, female nucleus near; fusion of the two nuclei shown in the two other figures. (After Berlese.) are not developed here, but a nucleus in the antheridium reaches the egg cell. It sinks in the protoplasm of the egg, comes in contact with the nu- cleus of the egg, and fuses with it. Thus fertilization is accomplished.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for re
![. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. ROOT CROPS. 47 and sand to be put on the ground before sowing the seeds. The odour of the tar is so offensive to insects that they cannot endure soil impregnated with it. (2) Burn all in- fested leaves. Cure.—Dressing the land with gas-lime, soot, and lime, destroys the pupss of this pest. The Parsnip Fly {Psila rosm) has already been described in this chapter (see " Carrot Fly ").. Fig. 19.—Mildew of Paesnips (Peronospora nivea). A. A spotted parsnip. B. Coniaiophore Stock Photo](https://c8.alamy.com/comp/RDGX6D/the-diseases-of-crops-and-their-remedies-a-handbook-of-economic-biology-for-farmers-and-students-plant-diseases-root-crops-47-and-sand-to-be-put-on-the-ground-before-sowing-the-seeds-the-odour-of-the-tar-is-so-offensive-to-insects-that-they-cannot-endure-soil-impregnated-with-it-2-burn-all-in-fested-leaves-curedressing-the-land-with-gas-lime-soot-and-lime-destroys-the-pupss-of-this-pest-the-parsnip-fly-psila-rosm-has-already-been-described-in-this-chapter-see-quot-carrot-fly-quot-fig-19mildew-of-paesnips-peronospora-nivea-a-a-spotted-parsnip-b-coniaiophore-RDGX6D.jpg ". The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. ROOT CROPS. 47 and sand to be put on the ground before sowing the seeds. The odour of the tar is so offensive to insects that they cannot endure soil impregnated with it. (2) Burn all in- fested leaves. Cure.—Dressing the land with gas-lime, soot, and lime, destroys the pupss of this pest. The Parsnip Fly {Psila rosm) has already been described in this chapter (see " Carrot Fly ").. Fig. 19.—Mildew of Paesnips (Peronospora nivea). A. A spotted parsnip. B. Coniaiophore Stock Photo")
RMRDGX6D–. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. ROOT CROPS. 47 and sand to be put on the ground before sowing the seeds. The odour of the tar is so offensive to insects that they cannot endure soil impregnated with it. (2) Burn all in- fested leaves. Cure.—Dressing the land with gas-lime, soot, and lime, destroys the pupss of this pest. The Parsnip Fly {Psila rosm) has already been described in this chapter (see " Carrot Fly ").. Fig. 19.—Mildew of Paesnips (Peronospora nivea). A. A spotted parsnip. B. Coniaiophore
RMRE1P2P–. Elementary botany. Botany. 232 MORPHOLOGY. size of the female nucleus before the fusion of the two takes place. In figs. 306 and 307 are shown the entering pollen tube with the sperm nucleus, and the fusion of the male and female nuclei. 457. Fertilization in plants is fundamentally the same as in animals.—In all the great groups of plants as represented by spirogyra, cedogonium, vaucheria, peronospora, ferns, gymno-. Fig. 304. Two- and four-celled stage of embryo-sac of lilium. The middle one shows division of nuclei to form the four-celled stage. (Easter lily.) sperms, and in the angiospen
RMRDDWJ6–. Diseases of plants induced by cryptogamic parasites : introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae . Plant diseases; Parasitic plants; Fungi. PERONOSPORA. 133 oospore-coat (oospores of P. viciae have a coat with a regular net- work). It occurs on stems, leaves, and petioles of clovers, lucerne and other Papilionaceae, often with disastrous effect. P. sparsa, Berk. (Britain and U.S. America). This parasite on the rose was first observed in England. It injures indoor roses, causing a fall of the leaf, preceded by the appearance of lilac-coloured spots which
RMRDE5MA–. Fungoid and insect pests of the farm. Agricultural pests. 34 Potato Disease and Allied Diseases [ch. disease from one season to another. The fungus does not attack the bulbs but prevents the leaves from carrying on their normal functions of manufacturing food stuff and so the bulbs are smaller.. Fig. 11. Conidiophore and conidia of Peronospora schUideni which causee onion mildew. (Magnified.) (After Massee.) Remedial Measures. Well-drained land does not suffer so much as wet land. Onions should not be planted on land which had a diseased crop of onions in the previous season.. Please note th
RMRDJH4J–. The essentials of botany. Botany. 140 BOTANY. fungus which protrude through the epidermis of the host. In the Mildews (species of Peronospora) these branches. Fig. 66.âShowing tips of two conidia-beaiing branches of Potato-mildew (Peronospora infestans). Highly magnified. find their way through the breathing-pores, and bear their spores singly upon lateral branchlets (Fig. 66); in the White Rusts (species of Cystopus) the conidia-bearing branches collect under the epidermis and rupture it. Here the coni- dia are borne in chains or bead-like rows (Fig. 67). 292. In some species the conidia ge
RMRDWG4D–. Nature and development of plants. Botany. Fig. 132. Fig. 133. Fig. 132. Asexual reproduction of the mildew: A, hyphae of Plasmo- para emerging from a stoma and bearing numerous sporangia. B, enlarged view of sporangium of Peronospora germinating on a dry leaf. In this case the sporangium behaves as a spore sending out a hypha that will penetrate the tissues of the leaf. C, sporangium of Phytophthora germinating in the water and forming zoospores. D, zoospore enlarged. E, zoospore has come to rest and is forming a tube that will penetrate the tissues of the leaf as in the case of 5. Fig. 133.
RMRE3CT2–. A handbook of cryptogamic botany. Cryptogams. Fig. 28S.—Simple sporophores of PhytophtJiora infestans de By. a, formation of fiist spores (zoosporanges) at ends of branches ; b^ two ripe spores on each branch and a third being formed {x about 200). (After de Bary.) Phytophthora, which resemble those of Peronospora in general habit, differ from them in the fact that each branch bears more than one pro- pagating body—not in chains, like Cystopus, but at intervals on the branch. In P. infestans a propagating cell is produced at the apex of each branch ; and as it ripens a papilla-like swelling
RMRDDYJ7–. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. ROOT CROPS. 43 reduce its vitality considerably. When artificial cultures were exposed to a temperature of —17° C. for one day, the organisms were completely destroyed. An E.M.F.i of 3'3 volts (at 17° C.) destroyed B. allii when growing in sterilized pork broth (neutral). Prevention.—Onions, lohen stored, should be kept in a. Fig. 17.— Onion Mildew (Peronospora ScUeideniana). A. The fuBgDS growing from the base of an onion leaf. B. Mycelium ramifying amongst the cells of the ho
RMRDPFYG–. My garden, its plan and culture together with a general description of its geology, botany, and natural history. Gardening. Fig. 8^4 (Z.âPeronospora vicis, magnified. Fig. 845.âLettuce Mould, magnified. Fig. 846.âAcremonium, magnified. Parsnips are attacked by another species of Peronospora, namely, P. nivea ; onions by a third, called P. Schleideniana ; peas by P. vicice (fig. 844^); lettuces by P. gangliformis (fig. 845); cabbages by P. para- sitica ;â and spinach by P. effusa. My TodecB have sometimes been attacked by a microscopic fungus, the Acremonium (fig. 846). It is a beautiful obje
RMRDGX6Y–. The diseases of crops and their remedies : a handbook of economic biology for farmers and students. Plant diseases. BOOT CROPS. 43 reduce its vitality considerably. When artificial cultures were exposed to a temperature of —17* C. for one day, the organisms were completely destroyed. An E.M.F.i of 3'3 volts (at 17° C.) destroyed B. allii when growing in sterilized pork broth (neutral). Prevention.—Onions, ivhen stored, should be kept in a. Fig. 17.— Onion Mildew (Peronospora Schleideniana). A. The fungus growing from the base of an onion leaf. B. Mycelium ramifying amongst the cells of the h
RMRDAAMD–. A text-book of botany for secondary schools. Botany. FUNGI 145 as apple, pear, cherry, rose, hop, grape, wheat, gooseberry, cucumber, pea, verbena, sunflower, aster, etc. In fact, very few seed-plants seem to escape their attacks. Being exter- nal parasites, mildews are not necessarily destructive; but they often cause the death of the host. An examination of the my- celium shows that its filaments have partition walls; and hence the body is not ccenocytic, as in Mucor and Peronospora, but made up of a row of cells as in the Conferva forms among the green Algae. Small disk-like outgrowths ar
RMRDJH48–. The essentials of botany. Botany. Fig. 66.âShowing tips of two conidia-beaiing branches of Potato-mildew (Peronospora infestans). Highly magnified. find their way through the breathing-pores, and bear their spores singly upon lateral branchlets (Fig. 66); in the White Rusts (species of Cystopus) the conidia-bearing branches collect under the epidermis and rupture it. Here the coni- dia are borne in chains or bead-like rows (Fig. 67). 292. In some species the conidia germi- nate by forming a tube; in others they divide internally and finally emit many zoospores. The latter eventually protrude
RMRDWF1D–. Elementary botany. Botany. 232 MORPHOLOG Y. size of the female nucleus before the fusion of the two takes place. In figs. 306 and 307 are shown the entering pollen tube with the sperm nucleus, and the fusion of the male and female nuclei. 457. Fertilization in plants is fundamentally the same as in animals.—In all the great groups of plants as represented by spirogyra, cedogonium, vaucheria, peronospora, ferns, gymno-. Two- and four-celled stage of embryo-sac of lilium. (Ea ' The middle one shows division of Fig- 3°4- -sac of lili nuclei to form the four-celled stage. (Easter lily.) sperms,
RMRDWBY6–. The essentials of botany. Botany. Fio. 66.—Showing tips of two conidia-beaiing branches of Potato-mildew (Peronospora infestans). Highly magnified. find their way through the hreathing-pores, and bear their spores singly upon lateral branchlets (Fig. 66); in the White Rusts (species of Cystopus) the conidia-bearing branches collect under the epidermis and rupture it. Here the coni- dia are borne in chains or bead-like rows (Fig. 67). 292. In some species the conidia germi- nate by forming a fube; in others they divide internally and finally emit many zoospores. The latter eventually protrude
RMRPXP40–. Text-book of botany, morphological and physiological. Botany. ^tnnz. FIG. 180.—Cystopus candidus. A branch of the mycelium growing at the apex t with haustoria h between the paren- chymatous cells of Lepidium sativum; B conidia-bearing branch of the mycelium; C, D, E formation of zoogonidia from the conidia; .F zoogonidia germinating; G a zoogonidium germinating on a stoma; H zoogonidium of Peronospora infestans penetrating through the epidermis of a potato-stem (after De Bary, x 400). and thus find their way^at once into the intercellular spaces. When the mycelium has once obtained a footin
RMRDE6WW–. The fungi which cause plant disease . Plant diseases; Fungi. 84 THE FUNGI WHICH CAUSE PLANT DISEASE timate branchlets arise radially; germ tube produced from the apex of the conidia 7. Bremia, p. 95. Conidiophores without subapical en- largements; conidia germinating from the side 8. Peronospora, p. 95. Phytophthora de Bary (p. 83) This genus is of especial interest on account of its one exceed- ingly destructive representative, P. infestans, which occupies an historic position in phytopathology as one of the earliest of para- sitic fungi to receive study in any way complete or adequate; stu
![. Diseases of truck crops and their control . Vegetables. Fig. 54. Onion Diseases. a. Downy mildew, b. mature conidiophore and conidia of Peronospora sckleideni, c. fertilization of the female oogomum by the male antheridium, d. oospore (a. to d. after Wh^tzd), e. onion smut, /, spore ball of the smut fungus, g. spore germina- tion, formation of sporidia at x, h. Vermicularia anthracnose, i. section through acervulis of Vermicidaria cirdnans, j. setae and spore formation in V. circinansXe. to g., *. and j". after Thaxter), k. pink root of onion, healthy and diseased bulbs, I. pirJc root o Stock Photo](https://c8.alamy.com/comp/RDEEXH/diseases-of-truck-crops-and-their-control-vegetables-fig-54-onion-diseases-a-downy-mildew-b-mature-conidiophore-and-conidia-of-peronospora-sckleideni-c-fertilization-of-the-female-oogomum-by-the-male-antheridium-d-oospore-a-to-d-after-whtzd-e-onion-smut-spore-ball-of-the-smut-fungus-g-spore-germina-tion-formation-of-sporidia-at-x-h-vermicularia-anthracnose-i-section-through-acervulis-of-vermicidaria-cirdnans-j-setae-and-spore-formation-in-v-circinansxe-to-g-and-jquot-after-thaxter-k-pink-root-of-onion-healthy-and-diseased-bulbs-i-pirjc-root-o-RDEEXH.jpg ". Diseases of truck crops and their control . Vegetables. Fig. 54. Onion Diseases. a. Downy mildew, b. mature conidiophore and conidia of Peronospora sckleideni, c. fertilization of the female oogomum by the male antheridium, d. oospore (a. to d. after Wh^tzd), e. onion smut, /, spore ball of the smut fungus, g. spore germina- tion, formation of sporidia at x, h. Vermicularia anthracnose, i. section through acervulis of Vermicidaria cirdnans, j. setae and spore formation in V. circinansXe. to g., *. and j". after Thaxter), k. pink root of onion, healthy and diseased bulbs, I. pirJc root o Stock Photo")
RMRDEEXH–. Diseases of truck crops and their control . Vegetables. Fig. 54. Onion Diseases. a. Downy mildew, b. mature conidiophore and conidia of Peronospora sckleideni, c. fertilization of the female oogomum by the male antheridium, d. oospore (a. to d. after Wh^tzd), e. onion smut, /, spore ball of the smut fungus, g. spore germina- tion, formation of sporidia at x, h. Vermicularia anthracnose, i. section through acervulis of Vermicidaria cirdnans, j. setae and spore formation in V. circinansXe. to g., *. and j". after Thaxter), k. pink root of onion, healthy and diseased bulbs, I. pirJc root o
RMRDE0MP–. Diseases of truck crops and their control . Vegetables. Fig. 20. Beet Diseases. fl. Crown gall, b. scab, c, downy mildew, d. Conidiophore of Peronospora schachtii arising from a stomate of an infected beet leaf, e. germinating zoospore of P. schach- tii,/. oospore of P. schachtii, g. Cercospora leaf spot (after Halsted), ft. conidiophore and conidia of Cercospora beticola (after Duggar), i, Phoma leaf spot (after Pool and McKay), k, pycnidium of Phoma beta (after T. Johnson) {d.-f. after PrilUeux).. Please note that these images are extracted from scanned page images that may have been digit
RMRDWG84–. Elementary botany. Botany. j?««SW w. W. SL .-5L-. £ 'â â $&: it J& Fig. 143. Fertilization in Peronospora alsinearum; tube from antheridium carrying in the sperm nucleus in figure at the left, female nucleus near; fusion of the two nuclei shown in the two Other figures. (After Berlese.) are not developed, here, but a nucleus in the antheridium reaches the egg cell. It sinks in the protoplasm of the Ggg, comes in contact with the nu- cleus of the egg, and fuses with it. Thus fertilization is accomplished.. Please note that these images are extracted from scanned page images that ma
RMRE1R52–. Nature and development of plants. Botany. 222 REPRODUCTION OF THE DOWNY MILDEWS does not appear until the latter part Of July. K only becomes of serious importance in sultry weather, when a short period of rain will result in the formation of the sporangia and whole fields will be devastated in a few days. ly. A Fig. 132. Fig. 133. Fig. 132. Asexual reproduction of the mildew: A, hyphae of Plasmo- para emerging from a stoma and bearing numerous sporangia. B, enlarged view of sporangium of Peronospora germinating on a dry leaf. In this case the sporangium behaves as a spore sending out a hyph
![. Danish fungi as represented in the herbarium of E. Rostrup;. Fungi. 66 Is considered by A. Fischer (IV"") to be identical with Per. poten- tillae de By. Rubus fiuticosus. S. Fredensborg (Vs 94 a ^°l8 95 see R 96 m ^^e). 70. Peronospora potentillae de By., Syll. VII "^ Fisch. IV " Potentilskimmel (R 04 a '^). May—October, rare. Potentilla reptans. S. Slagelse!. Geum urbanum. J. Knivholt Skov!. Alchi- milla vulgaris (= Peronospora akhimillae Otth. Syll. XIV ^^^, is most fre- quently found in company with Uromyces akhimillae. Jonstrup, Charlotten- lund (Oct. 88 Joh. Lange, Stock Photo](https://c8.alamy.com/comp/RE395J/danish-fungi-as-represented-in-the-herbarium-of-e-rostrup-fungi-66-is-considered-by-a-fischer-ivquotquot-to-be-identical-with-per-poten-tillae-de-by-rubus-fiuticosus-s-fredensborg-vs-94-a-l8-95-see-r-96-m-e-70-peronospora-potentillae-de-by-syll-vii-quot-fisch-iv-quot-potentilskimmel-r-04-a-mayoctober-rare-potentilla-reptans-s-slagelse!-geum-urbanum-j-knivholt-skov!-alchi-milla-vulgaris-=-peronospora-akhimillae-otth-syll-xiv-is-most-fre-quently-found-in-company-with-uromyces-akhimillae-jonstrup-charlotten-lund-oct-88-joh-lange-RE395J.jpg ". Danish fungi as represented in the herbarium of E. Rostrup;. Fungi. 66 Is considered by A. Fischer (IV"") to be identical with Per. poten- tillae de By. Rubus fiuticosus. S. Fredensborg (Vs 94 a ^°l8 95 see R 96 m ^^e). 70. Peronospora potentillae de By., Syll. VII "^ Fisch. IV " Potentilskimmel (R 04 a '^). May—October, rare. Potentilla reptans. S. Slagelse!. Geum urbanum. J. Knivholt Skov!. Alchi- milla vulgaris (= Peronospora akhimillae Otth. Syll. XIV ^^^, is most fre- quently found in company with Uromyces akhimillae. Jonstrup, Charlotten- lund (Oct. 88 Joh. Lange, Stock Photo")
RMRE395J–. Danish fungi as represented in the herbarium of E. Rostrup;. Fungi. 66 Is considered by A. Fischer (IV"") to be identical with Per. poten- tillae de By. Rubus fiuticosus. S. Fredensborg (Vs 94 a ^°l8 95 see R 96 m ^^e). 70. Peronospora potentillae de By., Syll. VII "^ Fisch. IV " Potentilskimmel (R 04 a '^). May—October, rare. Potentilla reptans. S. Slagelse!. Geum urbanum. J. Knivholt Skov!. Alchi- milla vulgaris (= Peronospora akhimillae Otth. Syll. XIV ^^^, is most fre- quently found in company with Uromyces akhimillae. Jonstrup, Charlotten- lund (Oct. 88 Joh. Lange,
RMRE2N66–. Elementary botany. Botany. Branching hj-pha of Peronospora alsinearum, Branched hypha of downy mildew of grape shoeing peculiar branching (Plasmopara viticola).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Atkinson, George Francis, 1854-1918. New York : H. Holt
![. Plant studies; an elementary botany. Botany. Fig. 'SA'.. a hrancti of Peronospora in contact with two cells of a host ])lant, and sending into them its large hanstoria.—After DeBakt.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Coulter, John Merle, 1851-1928. New York, D. Appleton and Company Stock Photo](https://c8.alamy.com/comp/RDHGBE/plant-studies-an-elementary-botany-botany-fig-sa-a-hrancti-of-peronospora-in-contact-with-two-cells-of-a-host-lant-and-sending-into-them-its-large-hanstoriaafter-debakt-please-note-that-these-images-are-extracted-from-scanned-page-images-that-may-have-been-digitally-enhanced-for-readability-coloration-and-appearance-of-these-illustrations-may-not-perfectly-resemble-the-original-work-coulter-john-merle-1851-1928-new-york-d-appleton-and-company-RDHGBE.jpg ". Plant studies; an elementary botany. Botany. Fig. 'SA'.. a hrancti of Peronospora in contact with two cells of a host ])lant, and sending into them its large hanstoria.—After DeBakt.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Coulter, John Merle, 1851-1928. New York, D. Appleton and Company Stock Photo")
RMRDHGBE–. Plant studies; an elementary botany. Botany. Fig. 'SA'.. a hrancti of Peronospora in contact with two cells of a host ])lant, and sending into them its large hanstoria.—After DeBakt.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Coulter, John Merle, 1851-1928. New York, D. Appleton and Company
RMRDXT8W–. A manual of poisonous plants, chiefly of eastern North America, with brief notes on economic and medicinal plants, and numerous illustrations. Poisonous plants. EUTHALLEPHYTA—EUM YCETES—OOM YCETES 205 Many members of this group are destructive parasites to cultivated plants like the potato rot fungus {Phytopthora infestans), the onion mildew (Peron- ospora Schleideniana), the lettuce mildew {Bremia Lactucae), the mildew of the sunflower (Plasmopara Halstedii), the Clover mildew {Peronospora tri- fcliorum) which may be injurious to animals, the millet mildew (^Sclerospora gra,:.inicola) which
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