Phytophthora Black & White Stock Photos
RF2BTGT0J–Potato leaves got infected by phytophthora infestans showing spots over leaves, vintage line drawing or engraving illustration.
RM2AJBH2K–The diseases and pests of the rubber tree . CLARET-COLOURED CANKERPatch exposed by shaving PHYTOPHTHORA DISEASES 113 forms a scale whicli ultimately falls ofE. In these cases of self healing, the resulting damage depends entirely on theextent to which the disease has spread. If it has not pene-trated completely through the cortex a scale is formed, of a. Fig. 12.—Hevea Canker, caused by Phytophihora Faheri ;cortex cut away to show tlie discoloured areas. thickness depending upon the depth of penetration, but thewood is not exposed. But if it has penetrated through to thewood, a large open woun
RMD9629N–Potato Famine: Irish peasant family unable to pay rent because of failure of potato crop due toPotato Blight (Phytophthora infestans), evicted from their tumbledown cottage. From 'The Illustrated London News' December 1848. Wood engraving
RMPG43RY–. Comparative morphology and biology of the fungi, mycetozoa and bacteria . Plant morphology; Fungi; Myxomycetes; Bacteriology. jo8 DIVISION I.—GENERAL MORPHOLOGY. posterior being directed backwards and dragged behind. In Phytophthora infestans, according to older observations which perhaps need revision, both cilia spring from a point on the posterior margin of the pellucid spot These 'beanshaped' zoospores are peculiar to the Peronosporeae and Saprolegnieae. Similar but not the same forms are found in certain Chytridieae (see section XLVI). In the genera Achlya, Achlyogeton, and Apbanomyces
RM2AJBG98–The diseases and pests of the rubber tree . ing to control the fruit disease by cutting ofidead branches and removing the green fruits. If the fruitsare removed the chief source of Black Thread infection isabolished. During an attack of fruit disease the fungusproduces spores in abundance on the diseased fruits, andthese, washed down, or splashed on to the tapping cut, setup Black Thread. From South India it is reported thaton one-estate on which dead branches and green fruits IV PHYTOPHTHORA DISEASES 123 had been removed over an area of 100 acres as an experiment,Black Thread was much less pr
RMD9629K–Potato Famine: Irish peasant family unable to pay rent because of failure of the potato crop due to Potato Blight (Phytophthora infestans), finding shelter in a hedgerow the day after eviction from their cottage. From 'The Illustrated London News', December 1848. Wood engraving.
![. Fungous diseases of plants : with chapters on physiology, culture methods and technique . Fungi in agriculture. 166 FUNGOUS DISEASES OF PLANTS and it has been the cause of great disaster in many potato-growing regions before methods for its control were well known. All who are familiar with the history of potato growing doubtless know of the potato famine of 1845. The serious famine in Ireland was very largely due to this failure of the potato crop, a failure due to the prevalence and "unusual destruc- tiveness of the Phytophthora. Distribution. At one time it was the current opinion th Stock Photo](https://c8.alamy.com/comp/PG3YXJ/fungous-diseases-of-plants-with-chapters-on-physiology-culture-methods-and-technique-fungi-in-agriculture-166-fungous-diseases-of-plants-and-it-has-been-the-cause-of-great-disaster-in-many-potato-growing-regions-before-methods-for-its-control-were-well-known-all-who-are-familiar-with-the-history-of-potato-growing-doubtless-know-of-the-potato-famine-of-1845-the-serious-famine-in-ireland-was-very-largely-due-to-this-failure-of-the-potato-crop-a-failure-due-to-the-prevalence-and-quotunusual-destruc-tiveness-of-the-phytophthora-distribution-at-one-time-it-was-the-current-opinion-th-PG3YXJ.jpg ". Fungous diseases of plants : with chapters on physiology, culture methods and technique . Fungi in agriculture. 166 FUNGOUS DISEASES OF PLANTS and it has been the cause of great disaster in many potato-growing regions before methods for its control were well known. All who are familiar with the history of potato growing doubtless know of the potato famine of 1845. The serious famine in Ireland was very largely due to this failure of the potato crop, a failure due to the prevalence and "unusual destruc- tiveness of the Phytophthora. Distribution. At one time it was the current opinion th Stock Photo")
RMPG3YXJ–. Fungous diseases of plants : with chapters on physiology, culture methods and technique . Fungi in agriculture. 166 FUNGOUS DISEASES OF PLANTS and it has been the cause of great disaster in many potato-growing regions before methods for its control were well known. All who are familiar with the history of potato growing doubtless know of the potato famine of 1845. The serious famine in Ireland was very largely due to this failure of the potato crop, a failure due to the prevalence and "unusual destruc- tiveness of the Phytophthora. Distribution. At one time it was the current opinion th
RMRDJFHC–. Fungous diseases of plants : with chapters on physiology, culture methods and technique . Fungi in agriculture. PHYCOMYCETES 169 4. Selection has not given visible increase of resistance. 5. Hybridization and the growing of seedling plants, followed by careful selection, seem to offer a more logical method of se- curing disease-resistant varieties than does selection. The tomato is occasionally subject to this disease, but so far as is now known it is not seriously affected in any part of the world. The fungus. The mycelium of the Phytophthora, like that of the other members of this family,
RMD9627X–Irish Potato Famine: Government potato store being attacked by starving inhabitants of Galway. The potato crop which, provided the staple food for the Irish peasantry, was destroyed by Potato Blight (Phytophthora infestans), the cause of the famine in which one million died of starvation and another 2.5 million were forced to emitrate. From 'The Illustrated London News', June 1842. Wood engraving.
RMPG4B3W–. Botany for agricultural students . Botany. POTATO BLIGHT (PHYTOPHTHORA INFESTANS) 357 scattered about like spores. When the conidia germinate, instead of producing hyphae they produce zoospores, which, after swimming about for a few minutes, lose their cilia and begin to produce new hyphae. If favorably located, the new hyphae find entrance to a leaf through its stomata and start the disease anew. The oogonia and antheridia resemble those of Saprolegnia, but are produced on short hyphae within the tissues of the host. The oospore has a heavy wall and is not liberated until the tissues of the
RMRJH11W–A cartoon commenting on the problems of Ireland. Illustrated by John Tenniel (1820-1914) an English illustrator, graphic humourist, and political cartoonist. Dated 19th century
RMRDWD5B–. Botany, with agricultural applications. Botany. POTATO BLIGHT (PHYTOPHTHORA INPESTANS) 357 scattered about like spores. When the conidia germinate, instead of producing hyphae they produce zoospores, which, after swimming about for a few minutes, lose their cilia and begin to produce new hyphae. If favorably located, the new hyphae find entrance to a leaf through its stomata and start the disease anew. The oogonja and antheridia resemble those of Saprolegnia, but are produced on short hyphae within the tissues of the host. The oospore has a heavy wall and is not liberated until the tissues o
RMPG3YXT–. Fungous diseases of plants : with chapters on physiology, culture methods and technique . Fungi in agriculture. PHYCOMYCETES 169 4. Selection has not given visible increase of resistance. 5. Hybridization and the growing of seedling plants, followed by careful selection, seem to offer a more logical method of se- curing disease-resistant varieties than does selection. The tomato is occasionally subject to this disease, but so far as is now known it is not seriously affected in any part of the world. The fungus. The mycelium of the Phytophthora, like that of the other members of this family,
![. Fungous diseases of plants : with chapters on physiology, culture methods and technique . Fungi in agriculture. 166 FUNGOUS DISEASES OF PLANTS and it has been the cause of great disaster in many potato-growing regions before methods for its control were well known. All who are familiar with the history of potato growing doubtless know of the potato famine of 1845. The serious famine in Ireland was very largely due to this failure of the potato crop, a failure due to the prevalence and "unusual destruc- tiveness of the Phytophthora. Distribution. At one time it was the current opinion th Stock Photo](https://c8.alamy.com/comp/RDJFJ9/fungous-diseases-of-plants-with-chapters-on-physiology-culture-methods-and-technique-fungi-in-agriculture-166-fungous-diseases-of-plants-and-it-has-been-the-cause-of-great-disaster-in-many-potato-growing-regions-before-methods-for-its-control-were-well-known-all-who-are-familiar-with-the-history-of-potato-growing-doubtless-know-of-the-potato-famine-of-1845-the-serious-famine-in-ireland-was-very-largely-due-to-this-failure-of-the-potato-crop-a-failure-due-to-the-prevalence-and-quotunusual-destruc-tiveness-of-the-phytophthora-distribution-at-one-time-it-was-the-current-opinion-th-RDJFJ9.jpg ". Fungous diseases of plants : with chapters on physiology, culture methods and technique . Fungi in agriculture. 166 FUNGOUS DISEASES OF PLANTS and it has been the cause of great disaster in many potato-growing regions before methods for its control were well known. All who are familiar with the history of potato growing doubtless know of the potato famine of 1845. The serious famine in Ireland was very largely due to this failure of the potato crop, a failure due to the prevalence and "unusual destruc- tiveness of the Phytophthora. Distribution. At one time it was the current opinion th Stock Photo")
RMRDJFJ9–. Fungous diseases of plants : with chapters on physiology, culture methods and technique . Fungi in agriculture. 166 FUNGOUS DISEASES OF PLANTS and it has been the cause of great disaster in many potato-growing regions before methods for its control were well known. All who are familiar with the history of potato growing doubtless know of the potato famine of 1845. The serious famine in Ireland was very largely due to this failure of the potato crop, a failure due to the prevalence and "unusual destruc- tiveness of the Phytophthora. Distribution. At one time it was the current opinion th
![. Diseases of plants induced by cryptogamic parasites : introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae . Plant diseases; Parasitic plants; Fungi. PHYTOPHTHORA. 119 Another parasite of conifer seedlings—Fusoma parasitictmi— which somewhat resembles Phytophtlwra, is figured and described amongst the " Fungi imperfecti." Phytophthora infestans, De Bary.^ This parasite was first observed in Europe in 1845, and has since then become. Fig. so. Fig. 29.—Celhilav tissue from diseased cotyledon of Beech. The starch-grains have been absorbed from the cell-pro Stock Photo](https://c8.alamy.com/comp/PG0R6N/diseases-of-plants-induced-by-cryptogamic-parasites-introduction-to-the-study-of-pathogenic-fungi-slime-fungi-bacteria-amp-algae-plant-diseases-parasitic-plants-fungi-phytophthora-119-another-parasite-of-conifer-seedlingsfusoma-parasitictmi-which-somewhat-resembles-phytophtlwra-is-figured-and-described-amongst-the-quot-fungi-imperfectiquot-phytophthora-infestans-de-bary-this-parasite-was-first-observed-in-europe-in-1845-and-has-since-then-become-fig-so-fig-29celhilav-tissue-from-diseased-cotyledon-of-beech-the-starch-grains-have-been-absorbed-from-the-cell-pro-PG0R6N.jpg ". Diseases of plants induced by cryptogamic parasites : introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae . Plant diseases; Parasitic plants; Fungi. PHYTOPHTHORA. 119 Another parasite of conifer seedlings—Fusoma parasitictmi— which somewhat resembles Phytophtlwra, is figured and described amongst the " Fungi imperfecti." Phytophthora infestans, De Bary.^ This parasite was first observed in Europe in 1845, and has since then become. Fig. so. Fig. 29.—Celhilav tissue from diseased cotyledon of Beech. The starch-grains have been absorbed from the cell-pro Stock Photo")
RMPG0R6N–. Diseases of plants induced by cryptogamic parasites : introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae . Plant diseases; Parasitic plants; Fungi. PHYTOPHTHORA. 119 Another parasite of conifer seedlings—Fusoma parasitictmi— which somewhat resembles Phytophtlwra, is figured and described amongst the " Fungi imperfecti." Phytophthora infestans, De Bary.^ This parasite was first observed in Europe in 1845, and has since then become. Fig. so. Fig. 29.—Celhilav tissue from diseased cotyledon of Beech. The starch-grains have been absorbed from the cell-pro
RMRDWC6E–. The essentials of botany. Botany. 188 PHYLUM IV. SIPHONOPHYCEAE branching tubes, whose cavities are continuous through- out. They usually grow between the cells of their hosts, and draw nourishment from them by means of little branches fhaustoria), which thrust them- selves through the walls. 277. The asexual spores (conidia) are produced upon branches (conidiophores) which protude through the epidermis of Fig. 78.—Piasmopara the host. In the Downy Mildews (Per- onospora, Phytophthora, Piasmopara, etc. )these branches find their way through the breath- ing-pores and bear their spores singly
![. Timber and some of its diseases. Timber; Trees. Xiil] ^^ damping OFF'' OF SEEDLING-TREES. 275 three days, and the whole sowing reduced to a putrid mass ; in drier seasons and soils, the spread of the infection may be slower, and only a patch here and. Fig. 42.—a young beech-seedling attacked by Phytophthora. cmnivora : the mori- bund tissues in the brown and black patches on the young stem, cotyledons, and leaves, are a prey to the fungus, the mycelium of which is spreading from the different centres. The horizontal line denotes the surface of the soil. T 2. Please note that these images are Stock Photo](https://c8.alamy.com/comp/PFXCNB/timber-and-some-of-its-diseases-timber-trees-xiil-damping-off-of-seedling-trees-275-three-days-and-the-whole-sowing-reduced-to-a-putrid-mass-in-drier-seasons-and-soils-the-spread-of-the-infection-may-be-slower-and-only-a-patch-here-and-fig-42a-young-beech-seedling-attacked-by-phytophthora-cmnivora-the-mori-bund-tissues-in-the-brown-and-black-patches-on-the-young-stem-cotyledons-and-leaves-are-a-prey-to-the-fungus-the-mycelium-of-which-is-spreading-from-the-different-centres-the-horizontal-line-denotes-the-surface-of-the-soil-t-2-please-note-that-these-images-are-PFXCNB.jpg ". Timber and some of its diseases. Timber; Trees. Xiil] ^^ damping OFF'' OF SEEDLING-TREES. 275 three days, and the whole sowing reduced to a putrid mass ; in drier seasons and soils, the spread of the infection may be slower, and only a patch here and. Fig. 42.—a young beech-seedling attacked by Phytophthora. cmnivora : the mori- bund tissues in the brown and black patches on the young stem, cotyledons, and leaves, are a prey to the fungus, the mycelium of which is spreading from the different centres. The horizontal line denotes the surface of the soil. T 2. Please note that these images are Stock Photo")
RMPFXCNB–. Timber and some of its diseases. Timber; Trees. Xiil] ^^ damping OFF'' OF SEEDLING-TREES. 275 three days, and the whole sowing reduced to a putrid mass ; in drier seasons and soils, the spread of the infection may be slower, and only a patch here and. Fig. 42.—a young beech-seedling attacked by Phytophthora. cmnivora : the mori- bund tissues in the brown and black patches on the young stem, cotyledons, and leaves, are a prey to the fungus, the mycelium of which is spreading from the different centres. The horizontal line denotes the surface of the soil. T 2. Please note that these images are
RMRE1N9Y–. College botany; structure, physiology and economics of plants. Botany. Fig. 126.—Albugo Candida showing the formation of the conidia spores just below the epider- mis of the host plant and also the antheridium and archegonium. swim for a few minutes m the moisture on the surface of the leaf, come to rest, lose their cilia and produce new hyphse which penetrate the leaf through the stomata. The oogonia and anthe- ridia are very similar to those of the Albugo. The late blight of the potato is in reality a mildew and is caused by a fungus (Phytophthora infestans). It is very similar to the grap
![. Minnesota plant diseases. Plant diseases. 536 Minnesota Plant Diseases. "Repeated sprayings with bordeaux about every ten days during a season, beginning at least by the middle of July, is useful in keeping this disease in check." The number of spray- ings is dependent on the season. In very wet seasons more may be necessary. If the under surfaces of the leaf can be sprayed, the results will be most successful, but great gain is possible by the ordinary method of spraying. Downy mildew of beans, peas, etc. (Phytophthora phaseoli Thaxt.). A downy mildew frequently attacks cultivated Stock Photo](https://c8.alamy.com/comp/PG4ENB/minnesota-plant-diseases-plant-diseases-536-minnesota-plant-diseases-quotrepeated-sprayings-with-bordeaux-about-every-ten-days-during-a-season-beginning-at-least-by-the-middle-of-july-is-useful-in-keeping-this-disease-in-checkquot-the-number-of-spray-ings-is-dependent-on-the-season-in-very-wet-seasons-more-may-be-necessary-if-the-under-surfaces-of-the-leaf-can-be-sprayed-the-results-will-be-most-successful-but-great-gain-is-possible-by-the-ordinary-method-of-spraying-downy-mildew-of-beans-peas-etc-phytophthora-phaseoli-thaxt-a-downy-mildew-frequently-attacks-cultivated-PG4ENB.jpg ". Minnesota plant diseases. Plant diseases. 536 Minnesota Plant Diseases. "Repeated sprayings with bordeaux about every ten days during a season, beginning at least by the middle of July, is useful in keeping this disease in check." The number of spray- ings is dependent on the season. In very wet seasons more may be necessary. If the under surfaces of the leaf can be sprayed, the results will be most successful, but great gain is possible by the ordinary method of spraying. Downy mildew of beans, peas, etc. (Phytophthora phaseoli Thaxt.). A downy mildew frequently attacks cultivated Stock Photo")
RMPG4ENB–. Minnesota plant diseases. Plant diseases. 536 Minnesota Plant Diseases. "Repeated sprayings with bordeaux about every ten days during a season, beginning at least by the middle of July, is useful in keeping this disease in check." The number of spray- ings is dependent on the season. In very wet seasons more may be necessary. If the under surfaces of the leaf can be sprayed, the results will be most successful, but great gain is possible by the ordinary method of spraying. Downy mildew of beans, peas, etc. (Phytophthora phaseoli Thaxt.). A downy mildew frequently attacks cultivated
RMRDD1NK–. Comparative morphology and biology of the fungi, mycetozoa and bacteria . Plant morphology; Fungi; Myxomycetes; Bacteriology. jo8 DIVISION I.—GENERAL MORPHOLOGY. posterior being directed backwards and dragged behind. In Phytophthora infestans, according to older observations which perhaps need revision, both cilia spring from a point on the posterior margin of the pellucid spot These 'beanshaped' zoospores are peculiar to the Peronosporeae and Saprolegnieae. Similar but not the same forms are found in certain Chytridieae (see section XLVI). In the genera Achlya, Achlyogeton, and Apbanomyces
RMPG41M4–. Elements of botany. Botany; Botany. 234 ELEMENTS OF BOTANY. The mycelium of these is generally concealed in the substance of the earth, decaying wood, or other material on which the fungus grows, and the conspicuous portion of the plant is that on which the spores are borne. Lichens, familiar objects encrusting rocks or hanging in. Fig. 201. — Spore-Formation in Potato Blight {Phytophthora infestans). A, an unbranched stalk, proceeding from the mycelium m in the interior of the potato leaf, passing out of the epidermis c through the stoma sp, and bearing a single spore-case ; JB, an older gr
RMRDD7NF–. Botany for agricultural students . Botany. POTATO BLIGHT (PHYTOPHTHORA INFESTANS) 357 scattered about like spores. When the conidia germinate, instead of producing hyphae they produce zoospores, which, after swimming about for a few minutes, lose their cilia and begin to produce new hyphae. If favorably located, the new hyphae find entrance to a leaf through its stomata and start the disease anew. The oogonia and antheridia resemble those of Saprolegnia, but are produced on short hyphae within the tissues of the host. The oospore has a heavy wall and is not liberated until the tissues of the
RMPG0R6M–. Diseases of plants induced by cryptogamic parasites : introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae . Plant diseases; Parasitic plants; Fungi. 120 PHYCoarrcETES. tufts, and form a white border round the brown parts of the leaf; they are monopodially branched and produce terminal sporangia (gonidia), which are easily detached. The sporangia on germination either pro- duce a varying number of zoospores, or germinate directly like conidia to form a mycelium capable of pro- ducing new conidia. The potato-disease is distin- guished from Phytophthora omnivora in
![. Cyclopedia of farm crops, a popular survey of crops and crop-making methods in the United States and Canada;. Farm produce; Agriculture. 524 POTATO POTATO Insects.— The flea-beetle (Crepidodera [Epitrix] cucumeris) attacks the leaves, puncturing them and thus furnishing an easy entrance for spores of dis- eases. Spraying with Bordeaux mixture as soon as the insects appear is of value. It acts as a deterrent. On the Pacific coast other flea-beetles occur, and for such the use of arsenites alone or in Bordeaux mixture is advised.. Fig. 752. Distributioii of late blieht {Phytophthora infestans) Stock Photo](https://c8.alamy.com/comp/RDR3A7/cyclopedia-of-farm-crops-a-popular-survey-of-crops-and-crop-making-methods-in-the-united-states-and-canada-farm-produce-agriculture-524-potato-potato-insects-the-flea-beetle-crepidodera-epitrix-cucumeris-attacks-the-leaves-puncturing-them-and-thus-furnishing-an-easy-entrance-for-spores-of-dis-eases-spraying-with-bordeaux-mixture-as-soon-as-the-insects-appear-is-of-value-it-acts-as-a-deterrent-on-the-pacific-coast-other-flea-beetles-occur-and-for-such-the-use-of-arsenites-alone-or-in-bordeaux-mixture-is-advised-fig-752-distributioii-of-late-blieht-phytophthora-infestans-RDR3A7.jpg ". Cyclopedia of farm crops, a popular survey of crops and crop-making methods in the United States and Canada;. Farm produce; Agriculture. 524 POTATO POTATO Insects.— The flea-beetle (Crepidodera [Epitrix] cucumeris) attacks the leaves, puncturing them and thus furnishing an easy entrance for spores of dis- eases. Spraying with Bordeaux mixture as soon as the insects appear is of value. It acts as a deterrent. On the Pacific coast other flea-beetles occur, and for such the use of arsenites alone or in Bordeaux mixture is advised.. Fig. 752. Distributioii of late blieht {Phytophthora infestans) Stock Photo")
RMRDR3A7–. Cyclopedia of farm crops, a popular survey of crops and crop-making methods in the United States and Canada;. Farm produce; Agriculture. 524 POTATO POTATO Insects.— The flea-beetle (Crepidodera [Epitrix] cucumeris) attacks the leaves, puncturing them and thus furnishing an easy entrance for spores of dis- eases. Spraying with Bordeaux mixture as soon as the insects appear is of value. It acts as a deterrent. On the Pacific coast other flea-beetles occur, and for such the use of arsenites alone or in Bordeaux mixture is advised.. Fig. 752. Distributioii of late blieht {Phytophthora infestans)
![. Timber and some of its diseases. Timber; Trees. xiil] "DAMPING OFF" OF SEEDLING-TREES. 277 simply boring through the cell-walls (Fig. 43). This process of boring through the cell-walls is due to the action of a solvent substance excreted by the growing. Fig. 43.—Portion of a cotyledon of the beech, infested w ith Phytophthora ojnnivora : the piece is shown partly in vertical section. The mycelium, spreading between the cells, puts forth aerial hyph<E, which bore between the cells of the epidermis, i, and d, or emerge from the stomata, a, and form conidia at their apices : the va Stock Photo](https://c8.alamy.com/comp/PFXCNA/timber-and-some-of-its-diseases-timber-trees-xiil-quotdamping-offquot-of-seedling-trees-277-simply-boring-through-the-cell-walls-fig-43-this-process-of-boring-through-the-cell-walls-is-due-to-the-action-of-a-solvent-substance-excreted-by-the-growing-fig-43portion-of-a-cotyledon-of-the-beech-infested-w-ith-phytophthora-ojnnivora-the-piece-is-shown-partly-in-vertical-section-the-mycelium-spreading-between-the-cells-puts-forth-aerial-hyphlte-which-bore-between-the-cells-of-the-epidermis-i-and-d-or-emerge-from-the-stomata-a-and-form-conidia-at-their-apices-the-va-PFXCNA.jpg ". Timber and some of its diseases. Timber; Trees. xiil] "DAMPING OFF" OF SEEDLING-TREES. 277 simply boring through the cell-walls (Fig. 43). This process of boring through the cell-walls is due to the action of a solvent substance excreted by the growing. Fig. 43.—Portion of a cotyledon of the beech, infested w ith Phytophthora ojnnivora : the piece is shown partly in vertical section. The mycelium, spreading between the cells, puts forth aerial hyph<E, which bore between the cells of the epidermis, i, and d, or emerge from the stomata, a, and form conidia at their apices : the va Stock Photo")
RMPFXCNA–. Timber and some of its diseases. Timber; Trees. xiil] "DAMPING OFF" OF SEEDLING-TREES. 277 simply boring through the cell-walls (Fig. 43). This process of boring through the cell-walls is due to the action of a solvent substance excreted by the growing. Fig. 43.—Portion of a cotyledon of the beech, infested w ith Phytophthora ojnnivora : the piece is shown partly in vertical section. The mycelium, spreading between the cells, puts forth aerial hyph<E, which bore between the cells of the epidermis, i, and d, or emerge from the stomata, a, and form conidia at their apices : the va
RMRE0P8J–. Elementary botany. Botany. 126 MORPHOLOG Y. power the two cilia on the end may be seen, or we may make them more distinct by treatment with Schultz's solution, draw- ing some under the cover glass. The zoogonidium is oval and the cilia are at the pointed end. After they have been at rest. Fig. 139- Downy mildew of grape (Plasinopora viti- cola), sliowingtuft or gonidiophores bearing gonidia, also intercellular mycelium. Millardet.) (After Fig. 140. Phytophthora infestans showing pe- culiar branches; gonidia below. for some time they often slip out of the thin wall, and swim again, this time
RMPG45GJ–. The fungi which cause plant disease . Plant diseases; Fungi. Fia. 416.—Sporodesmium antiquum. After Sac- caxdo. S. exitiosum var. solani Schenck is reported as the cause of a potato disease. S. solani-varians Yanha is the cause of potato disease in Europe, the foliage bearing brown spots and finally dying in a manner resembling death caused by Phytophthora. Cladosporium and pycnidial forms are said to exist. S. mucosum Sacc. was reported by Ader- holt on cucumber fruit and leaves causing disease. S. scorzonerae Aderh. causes a salsify stem and leaf disease.'^* Other parasitic species are: S.
RMRDWPNH–. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. PHYTOPHTHORA 233 the ground, they can, in the presence of moisture, produce zoo- spores, as in Cysiopns. The first signs of disease are discoloured spots exhibiting a dark central region surrounded by successive zones of greyish and pale green tissue, which rapidly become brown or even blackish ; closer inspection discloses the white. Fig. 124.—Asexual reproduction in various Oomycetes. A, Small part of epidermis of Potato-leaf, infected with Blight (Phytophthora infes- ians), showing branched hypha; bearing
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
![. Diseases of plants induced by cryptogamic parasites : introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae . Plant diseases; Parasitic plants; Fungi. PHYTOPHTHORA. 119 Another parasite of conifer seedlings—Fusoma parasitictmi— which somewhat resembles Phytophtlwra, is figured and described amongst the " Fungi imperfecti." Phytophthora infestans, De Bary.^ This parasite was first observed in Europe in 1845, and has since then become. Fig. so. Fig. 29.—Celhilav tissue from diseased cotyledon of Beech. The starch-grains have been absorbed from the cell-pro Stock Photo](https://c8.alamy.com/comp/RDDWNT/diseases-of-plants-induced-by-cryptogamic-parasites-introduction-to-the-study-of-pathogenic-fungi-slime-fungi-bacteria-amp-algae-plant-diseases-parasitic-plants-fungi-phytophthora-119-another-parasite-of-conifer-seedlingsfusoma-parasitictmi-which-somewhat-resembles-phytophtlwra-is-figured-and-described-amongst-the-quot-fungi-imperfectiquot-phytophthora-infestans-de-bary-this-parasite-was-first-observed-in-europe-in-1845-and-has-since-then-become-fig-so-fig-29celhilav-tissue-from-diseased-cotyledon-of-beech-the-starch-grains-have-been-absorbed-from-the-cell-pro-RDDWNT.jpg ". Diseases of plants induced by cryptogamic parasites : introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae . Plant diseases; Parasitic plants; Fungi. PHYTOPHTHORA. 119 Another parasite of conifer seedlings—Fusoma parasitictmi— which somewhat resembles Phytophtlwra, is figured and described amongst the " Fungi imperfecti." Phytophthora infestans, De Bary.^ This parasite was first observed in Europe in 1845, and has since then become. Fig. so. Fig. 29.—Celhilav tissue from diseased cotyledon of Beech. The starch-grains have been absorbed from the cell-pro Stock Photo")
RMRDDWNT–. Diseases of plants induced by cryptogamic parasites : introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae . Plant diseases; Parasitic plants; Fungi. PHYTOPHTHORA. 119 Another parasite of conifer seedlings—Fusoma parasitictmi— which somewhat resembles Phytophtlwra, is figured and described amongst the " Fungi imperfecti." Phytophthora infestans, De Bary.^ This parasite was first observed in Europe in 1845, and has since then become. Fig. so. Fig. 29.—Celhilav tissue from diseased cotyledon of Beech. The starch-grains have been absorbed from the cell-pro
RMPG0R6E–. Diseases of plants induced by cryptogamic parasites : introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae . Plant diseases; Parasitic plants; Fungi. PHYTOPHTHORA. 121. Fig. 32.—Pkytopkthora infestans. The Potato disease. A, Potato leaf with brown spots and white patches of fuDgi on the lower side. £, Groups of conidio- phores emerging from a stoma close beside a hair of the potato leaf. C, Conidio- phores and conidia, much enlarged. B, Leaf of potato much shrivelled up and brown, as in the later stages of the disea-se. (y. Tubeuf del.). Please note that these im
RMRDWG8F–. Elementary botany. Botany. 126 MOfiPHOLOG Y. power the two cilia on the end may be seen, or we may make them more distinct by treatment with Schultz's solution, draw- ing some under the cover glass. The zoogonidium is oval and the cilia are at the pointed end. After they have been at rest. Fig. 139- Downy mildew of grape (Plasmopora viti- cola), showing tuft of gonidiophores bearing gonidia, also intercellular mycelium. (After Millardet.) Fig. 140. Phytophthora infestans showing pe- culiar branches; gonidia below. for some time they often slip out of the thin wall, and swim again, this time
RMPG0R6J–. Comparative morphology and biology of the fungi, mycetozoa and bacteria . Plant morphology; Fungi; Myxomycetes; Bacteriology. Frc. 64. Phytophthora infestans. Eiti«imties*of two simple sporophores. (zfor. marion of the first gonidia on the tip of each branch, b two ripe gonidia on each branch, a third beginning to form. Magn. about 200 times.. Fig. 65. Phytophthara infestatts. a sporangium in water after the division is completed, b escape of the ten swarm-spores from the sporangium, c spores in the motile state, rf spores come to rest and beginning to germinate. Magn. 390 times.. Please not
![. Fundamentals of botany. Botany. 292 STRUCTURE AND LIFE HISTORIES This fungus is known as Albugo Candida, or more recently as Cystopus candidus. 4. Downy mildew of grapes and cucumbers.. Fig. 214.—Witches' brooms on the hackberry {Celtis occidenlalis), caused by a gall-mite {Phytoptus Sp.), or possibly by the mite in conjunc- tion with a powdery mildew {Sphcerotheca phytoptophyla), which is usually found on the "brooms." 5. Potato rot and "late blight," Phytophthora injestans (Mont). DeBary. This disease was the cause of the failure of the potato crop and the consequent fa Stock Photo](https://c8.alamy.com/comp/RE2FHM/fundamentals-of-botany-botany-292-structure-and-life-histories-this-fungus-is-known-as-albugo-candida-or-more-recently-as-cystopus-candidus-4-downy-mildew-of-grapes-and-cucumbers-fig-214witches-brooms-on-the-hackberry-celtis-occidenlalis-caused-by-a-gall-mite-phytoptus-sp-or-possibly-by-the-mite-in-conjunc-tion-with-a-powdery-mildew-sphcerotheca-phytoptophyla-which-is-usually-found-on-the-quotbroomsquot-5-potato-rot-and-quotlate-blightquot-phytophthora-injestans-mont-debary-this-disease-was-the-cause-of-the-failure-of-the-potato-crop-and-the-consequent-fa-RE2FHM.jpg ". Fundamentals of botany. Botany. 292 STRUCTURE AND LIFE HISTORIES This fungus is known as Albugo Candida, or more recently as Cystopus candidus. 4. Downy mildew of grapes and cucumbers.. Fig. 214.—Witches' brooms on the hackberry {Celtis occidenlalis), caused by a gall-mite {Phytoptus Sp.), or possibly by the mite in conjunc- tion with a powdery mildew {Sphcerotheca phytoptophyla), which is usually found on the "brooms." 5. Potato rot and "late blight," Phytophthora injestans (Mont). DeBary. This disease was the cause of the failure of the potato crop and the consequent fa Stock Photo")
RMRE2FHM–. Fundamentals of botany. Botany. 292 STRUCTURE AND LIFE HISTORIES This fungus is known as Albugo Candida, or more recently as Cystopus candidus. 4. Downy mildew of grapes and cucumbers.. Fig. 214.—Witches' brooms on the hackberry {Celtis occidenlalis), caused by a gall-mite {Phytoptus Sp.), or possibly by the mite in conjunc- tion with a powdery mildew {Sphcerotheca phytoptophyla), which is usually found on the "brooms." 5. Potato rot and "late blight," Phytophthora injestans (Mont). DeBary. This disease was the cause of the failure of the potato crop and the consequent fa
RMPG4CEH–. Diseases of truck crops and their control . Vegetables. Fig. 6i. Potato Diseases. a. Black wart (after Gussow), b. late blight on foliage, c, late blight on tuber, d. successive stages of the development of the conidia of Phyiophthora infestans (6. and d. after L. R. Jones), e, germination of conidia of Phytophthora infestans, by means of zoopores (after Ward),/, mature oogonium of P. infestans (after Clinton), g. melters, surface view, early stage of infection, h. pycnidium of Phoma tuherosa (after Melhus and Rosenbaum).. Please note that these images are extracted from scanned page images
![. Timber and some of its diseases. Timber; Trees. Xiil] ^^ damping OFF'' OF SEEDLING-TREES. 275 three days, and the whole sowing reduced to a putrid mass ; in drier seasons and soils, the spread of the infection may be slower, and only a patch here and. Fig. 42.—a young beech-seedling attacked by Phytophthora. cmnivora : the mori- bund tissues in the brown and black patches on the young stem, cotyledons, and leaves, are a prey to the fungus, the mycelium of which is spreading from the different centres. The horizontal line denotes the surface of the soil. T 2. Please note that these images are Stock Photo](https://c8.alamy.com/comp/RD8FN2/timber-and-some-of-its-diseases-timber-trees-xiil-damping-off-of-seedling-trees-275-three-days-and-the-whole-sowing-reduced-to-a-putrid-mass-in-drier-seasons-and-soils-the-spread-of-the-infection-may-be-slower-and-only-a-patch-here-and-fig-42a-young-beech-seedling-attacked-by-phytophthora-cmnivora-the-mori-bund-tissues-in-the-brown-and-black-patches-on-the-young-stem-cotyledons-and-leaves-are-a-prey-to-the-fungus-the-mycelium-of-which-is-spreading-from-the-different-centres-the-horizontal-line-denotes-the-surface-of-the-soil-t-2-please-note-that-these-images-are-RD8FN2.jpg ". Timber and some of its diseases. Timber; Trees. Xiil] ^^ damping OFF'' OF SEEDLING-TREES. 275 three days, and the whole sowing reduced to a putrid mass ; in drier seasons and soils, the spread of the infection may be slower, and only a patch here and. Fig. 42.—a young beech-seedling attacked by Phytophthora. cmnivora : the mori- bund tissues in the brown and black patches on the young stem, cotyledons, and leaves, are a prey to the fungus, the mycelium of which is spreading from the different centres. The horizontal line denotes the surface of the soil. T 2. Please note that these images are Stock Photo")
RMRD8FN2–. Timber and some of its diseases. Timber; Trees. Xiil] ^^ damping OFF'' OF SEEDLING-TREES. 275 three days, and the whole sowing reduced to a putrid mass ; in drier seasons and soils, the spread of the infection may be slower, and only a patch here and. Fig. 42.—a young beech-seedling attacked by Phytophthora. cmnivora : the mori- bund tissues in the brown and black patches on the young stem, cotyledons, and leaves, are a prey to the fungus, the mycelium of which is spreading from the different centres. The horizontal line denotes the surface of the soil. T 2. Please note that these images are
![. Lectures on the evolution of plants. Botany; Plants. 82 EVOLUTION OF PLANTS the fungi known as white-rusts and mildews. Of the latter the potato-fungus, Phytophthora infestans, the cause of the destructive " potato-rot," is one of the most familiar. The water-moulds (Saprolegniacese), (Fig. 21, A, D) are aquatic fungi, either saprophytes on the dead hodies. Fig. 21 (Phycomyoetes). — A, a dead fly covered with a growth of water- mould (Saprolegnia); 6, a sporangium of Saprolegnia about to open; C, a single zoospore; D, part of a plant of Saprolegnia with two young oogonia, og; E, a Stock Photo](https://c8.alamy.com/comp/PG1Y48/lectures-on-the-evolution-of-plants-botany-plants-82-evolution-of-plants-the-fungi-known-as-white-rusts-and-mildews-of-the-latter-the-potato-fungus-phytophthora-infestans-the-cause-of-the-destructive-quot-potato-rotquot-is-one-of-the-most-familiar-the-water-moulds-saprolegniacese-fig-21-a-d-are-aquatic-fungi-either-saprophytes-on-the-dead-hodies-fig-21-phycomyoetes-a-a-dead-fly-covered-with-a-growth-of-water-mould-saprolegnia-6-a-sporangium-of-saprolegnia-about-to-open-c-a-single-zoospore-d-part-of-a-plant-of-saprolegnia-with-two-young-oogonia-og-e-a-PG1Y48.jpg ". Lectures on the evolution of plants. Botany; Plants. 82 EVOLUTION OF PLANTS the fungi known as white-rusts and mildews. Of the latter the potato-fungus, Phytophthora infestans, the cause of the destructive " potato-rot," is one of the most familiar. The water-moulds (Saprolegniacese), (Fig. 21, A, D) are aquatic fungi, either saprophytes on the dead hodies. Fig. 21 (Phycomyoetes). — A, a dead fly covered with a growth of water- mould (Saprolegnia); 6, a sporangium of Saprolegnia about to open; C, a single zoospore; D, part of a plant of Saprolegnia with two young oogonia, og; E, a Stock Photo")
RMPG1Y48–. Lectures on the evolution of plants. Botany; Plants. 82 EVOLUTION OF PLANTS the fungi known as white-rusts and mildews. Of the latter the potato-fungus, Phytophthora infestans, the cause of the destructive " potato-rot," is one of the most familiar. The water-moulds (Saprolegniacese), (Fig. 21, A, D) are aquatic fungi, either saprophytes on the dead hodies. Fig. 21 (Phycomyoetes). — A, a dead fly covered with a growth of water- mould (Saprolegnia); 6, a sporangium of Saprolegnia about to open; C, a single zoospore; D, part of a plant of Saprolegnia with two young oogonia, og; E, a
RMRE3CWN–. A handbook of cryptogamic botany. Cryptogams. 314 FUNGI of simple germination by the emission of a germ^tube is manifest. The example of Phytophthora infestans (de By.) illustrates this. The acro- genously-formed zoosporange pro- duces zoospores in pure water containing free oxygen in fair amount. In nutrient solutions, on the other hand, no zoospores are formed, and the potential zoospo- range simply emits germ-tubes. Germination of spores, however, takes place characteristically in fungi by the emission of germ- tubes under conditions of tempe- rature, moisture, and the like presently to b
RMPG45GR–. The fungi which cause plant disease . Plant diseases; Fungi. THE FUNGI WHICH CAUSE PLANT DISEASE 617. Fia. 416.—Sporodesmium antiquum. After Sac- caxdo. S. exitiosum var. solani Schenck is reported as the cause of a potato disease. S. solani-varians Yanha is the cause of potato disease in Europe, the foliage bearing brown spots and finally dying in a manner resembling death caused by Phytophthora. Cladosporium and pycnidial forms are said to exist. S. mucosum Sacc. was reported by Ader- holt on cucumber fruit and leaves causing disease. S. scorzonerae Aderh. causes a salsify stem and leaf di
![. Timber and some of its diseases. Timber; Trees. xiil] "DAMPING OFF" OF SEEDLING-TREES. 277 simply boring through the cell-walls (Fig. 43). This process of boring through the cell-walls is due to the action of a solvent substance excreted by the growing. Fig. 43.—Portion of a cotyledon of the beech, infested w ith Phytophthora ojnnivora : the piece is shown partly in vertical section. The mycelium, spreading between the cells, puts forth aerial hyph<E, which bore between the cells of the epidermis, i, and d, or emerge from the stomata, a, and form conidia at their apices : the va Stock Photo](https://c8.alamy.com/comp/RD8FMT/timber-and-some-of-its-diseases-timber-trees-xiil-quotdamping-offquot-of-seedling-trees-277-simply-boring-through-the-cell-walls-fig-43-this-process-of-boring-through-the-cell-walls-is-due-to-the-action-of-a-solvent-substance-excreted-by-the-growing-fig-43portion-of-a-cotyledon-of-the-beech-infested-w-ith-phytophthora-ojnnivora-the-piece-is-shown-partly-in-vertical-section-the-mycelium-spreading-between-the-cells-puts-forth-aerial-hyphlte-which-bore-between-the-cells-of-the-epidermis-i-and-d-or-emerge-from-the-stomata-a-and-form-conidia-at-their-apices-the-va-RD8FMT.jpg ". Timber and some of its diseases. Timber; Trees. xiil] "DAMPING OFF" OF SEEDLING-TREES. 277 simply boring through the cell-walls (Fig. 43). This process of boring through the cell-walls is due to the action of a solvent substance excreted by the growing. Fig. 43.—Portion of a cotyledon of the beech, infested w ith Phytophthora ojnnivora : the piece is shown partly in vertical section. The mycelium, spreading between the cells, puts forth aerial hyph<E, which bore between the cells of the epidermis, i, and d, or emerge from the stomata, a, and form conidia at their apices : the va Stock Photo")
RMRD8FMT–. Timber and some of its diseases. Timber; Trees. xiil] "DAMPING OFF" OF SEEDLING-TREES. 277 simply boring through the cell-walls (Fig. 43). This process of boring through the cell-walls is due to the action of a solvent substance excreted by the growing. Fig. 43.—Portion of a cotyledon of the beech, infested w ith Phytophthora ojnnivora : the piece is shown partly in vertical section. The mycelium, spreading between the cells, puts forth aerial hyph<E, which bore between the cells of the epidermis, i, and d, or emerge from the stomata, a, and form conidia at their apices : the va
RMPG43P0–. Comparative morphology and biology of the fungi, mycetozoa and bacteria . Plant morphology; Fungi; Myxomycetes; Bacteriology. Fig. S3. Phytophthora infestans, Mont, a a sporangium lying in water alter the division is complete, b escape of the lo swarm- spores from the sporangium. £-spores in the motile state, rf spores at rest and beginning to germinate. Magn. 390 times. Fig. 54. Cladochytrium Iridis. a resting- spore with a brown membrane seen from the broad side, b the same rotated through 90°, in the centre is a large fatty spherical body. c-€ successive stages of germination of a single
RMRDHFPD–. Elements of botany. Botany; Botany. 234 ELEMENTS OF BOTANY. The mycelium of these is generally concealed in the substance of the earth, decaying wood, or other material on which the fungus grows, and the conspicuous portion of the plant is that on which the spores are borne. Lichens, familiar objects encrusting rocks or hanging in. Fig. 201. — Spore-Formation in Potato Blight {Phytophthora infestans). A, an unbranched stalk, proceeding from the mycelium m in the interior of the potato leaf, passing out of the epidermis c through the stoma sp, and bearing a single spore-case ; JB, an older gr
RMPG41GD–. Essentials of botany. Botany; Botany. THE FUNGI 249 (Sect. 315). The zygospore formation of bread-mold consid- erably resembles the mode of spore production in Spirogyra (Sect. 282), but the mold gametes contain many nuclei.. Fig. 174. Spore-Formation in Potato-Blight {Phytophthora infestaris), one of tHe algal fungi. A, a well-developed group of stalks, proceeding from a mass of mycelium inside the leaf and escaping through a stoma; B, a young, unbranched stalk, h, hyphae of mycehum; o, stoma; s, spore. (Both figures greatly magnified, S more than A.) It appears highly probable that such al
![. Minnesota plant diseases. Plant diseases. 536 Minnesota Plant Diseases. "Repeated sprayings with bordeaux about every ten days during a season, beginning at least by the middle of July, is useful in keeping this disease in check." The number of spray- ings is dependent on the season. In very wet seasons more may be necessary. If the under surfaces of the leaf can be sprayed, the results will be most successful, but great gain is possible by the ordinary method of spraying. Downy mildew of beans, peas, etc. (Phytophthora phaseoli Thaxt.). A downy mildew frequently attacks cultivated Stock Photo](https://c8.alamy.com/comp/RDE37M/minnesota-plant-diseases-plant-diseases-536-minnesota-plant-diseases-quotrepeated-sprayings-with-bordeaux-about-every-ten-days-during-a-season-beginning-at-least-by-the-middle-of-july-is-useful-in-keeping-this-disease-in-checkquot-the-number-of-spray-ings-is-dependent-on-the-season-in-very-wet-seasons-more-may-be-necessary-if-the-under-surfaces-of-the-leaf-can-be-sprayed-the-results-will-be-most-successful-but-great-gain-is-possible-by-the-ordinary-method-of-spraying-downy-mildew-of-beans-peas-etc-phytophthora-phaseoli-thaxt-a-downy-mildew-frequently-attacks-cultivated-RDE37M.jpg ". Minnesota plant diseases. Plant diseases. 536 Minnesota Plant Diseases. "Repeated sprayings with bordeaux about every ten days during a season, beginning at least by the middle of July, is useful in keeping this disease in check." The number of spray- ings is dependent on the season. In very wet seasons more may be necessary. If the under surfaces of the leaf can be sprayed, the results will be most successful, but great gain is possible by the ordinary method of spraying. Downy mildew of beans, peas, etc. (Phytophthora phaseoli Thaxt.). A downy mildew frequently attacks cultivated Stock Photo")
RMRDE37M–. Minnesota plant diseases. Plant diseases. 536 Minnesota Plant Diseases. "Repeated sprayings with bordeaux about every ten days during a season, beginning at least by the middle of July, is useful in keeping this disease in check." The number of spray- ings is dependent on the season. In very wet seasons more may be necessary. If the under surfaces of the leaf can be sprayed, the results will be most successful, but great gain is possible by the ordinary method of spraying. Downy mildew of beans, peas, etc. (Phytophthora phaseoli Thaxt.). A downy mildew frequently attacks cultivated
RMRE0P89–. Elementary botany. Botany. Fig. 141. Fig. 142. Gonidiophores and gonidia of potato blight (Phytophthora in- Gonidia o£ potato festans). ^, an older stage showing liow the brancli enlarges where blight forming zoogo- it grows beyond the older gonidium. (After de Bary.) nidia. ^After de Bary.) the eggs mature without fertilization. This maturity of the egg without fertilization is called partlienogenesis, which occurs in other plants also, but is a rather rare phenomenon. 284. In fig. 136 is shown the oogonium and an antheridium, and the antheridium is carrying in the male nucleus to the egg c
RMRDWG8C–. Elementary botany. Botany. FUNGI: SAPROLEGNIA. 127 after this process has taken place. Sometimes the slender antheridium can be seen coiled partly around the oogonium, and one end entering to come in contact with the egg cell. But in some species the antheridium is not present, and that is the case with the species figured at 135. In this case. li. Fig. 142. Gonidiophores and gonidia of potato blight (Phytophthora in- Gonidia of potato festans). b, an older stage showing how the branch enlarges where blight forming zoogo- it grows beyond the older goniduim. (After de Bary.) nidia. After de
RMRDDWNG–. Diseases of plants induced by cryptogamic parasites : introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae . Plant diseases; Parasitic plants; Fungi. 120 PHYCoarrcETES. tufts, and form a white border round the brown parts of the leaf; they are monopodially branched and produce terminal sporangia (gonidia), which are easily detached. The sporangia on germination either pro- duce a varying number of zoospores, or germinate directly like conidia to form a mycelium capable of pro- ducing new conidia. The potato-disease is distin- guished from Phytophthora omnivora in
RMRDWG88–. Elementary botany. Botany. li. Fig. 142. Gonidiophores and gonidia of potato blight (Phytophthora in- Gonidia of potato festans). b, an older stage showing how the branch enlarges where blight forming zoogo- it grows beyond the older goniduim. (After de Bary.) nidia. After de Bary.) the eggs mature without fertilization. This maturity of the egg without fertilization is calledparlh^w^Lin-sis, which occurs in other plants also, but is a rather rare phenomenon. 284- In fig. 136 is shown the oogonium and an antheridium, and the antheridium is carrying in the male nucleus to the egg cell. Sperm
RMRE0P8E–. Elementary botany. Botany. FUNGI: SAPROLEGNIA. 127 after this process has taken place. Sometimes the slender antheridium can be seen coiled partly around the oogonium, and one end entering to come in contact with the egg cell. But in some species the antheridmm is not present, and that is the case with the species figured at 135. In this case. Fig. 141. Fig. 142. Gonidiophores and gonidia of potato blight (Phytophthora in- Gonidia o£ potato festans). ^, an older stage showing liow the brancli enlarges where blight forming zoogo- it grows beyond the older gonidium. (After de Bary.) nidia. ^Af
RMRDR3A4–. Cyclopedia of farm crops, a popular survey of crops and crop-making methods in the United States and Canada;. Farm produce; Agriculture. Fig. 752. Distributioii of late blieht {Phytophthora infestans) of potato Indicated by lines, and of cot- ton-wilt {Neocosmospora vasinfecta) indicated by dots. Yearbook, Department of Agriculture, 1903. The potato-bug or Colorado potato-beetle (Do- ry phora deeemlineata, Fig. 753), the larva of which attacks the foliage, is destroyed by spraying with Paris green or some other arsenite in a solution, preferably Bordeaux mixture, using one-fourth to one-half
RMRDE0AD–. Diseases of truck crops and their control . Vegetables. Fig. 6i. Potato Diseases. a. Black wart (after Gussow), b. late blight on foliage, c, late blight on tuber, d. successive stages of the development of the conidia of Phyiophthora infestans (6. and d. after L. R. Jones), e, germination of conidia of Phytophthora infestans, by means of zoopores (after Ward),/, mature oogonium of P. infestans (after Clinton), g. melters, surface view, early stage of infection, h. pycnidium of Phoma tuherosa (after Melhus and Rosenbaum).. Please note that these images are extracted from scanned page images
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.
RMRE3CXE–. A handbook of cryptogamic botany. Cryptogams. Fig. 271.— Section through sclerote oK Schrotinta ScUrotiortiin Lib., showing its cortical medullary tissue (X 375). (After de Bary.) commonly characterised by the' bearing of spores, or special spore- mother-cells, on definite regions and in more or less definite arrange- ment. They form, as a rule, that portion of the whole organism which. Fig. 272.— Simple sporophores of Phytophthora infestans de By. a, formation of finst spore.s (zoosporanges) at ends of branches: b, two ripe spores on each branch and a third being formed ( x about 200). (Aft
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
![. Lectures on the evolution of plants. Botany; Plants. 82 EVOLUTION OF PLANTS the fungi known as white-rusts and mildews. Of the latter the potato-fungus, Phytophthora infestans, the cause of the destructive " potato-rot," is one of the most familiar. The water-moulds (Saprolegniaceae), (Fig. 21, A, D) are aquatic fungi, either saprophytes on the dead bodies. Fig. 21 (Phycomycetes). — A, a dead fly covered with a growth of water- mould (Saprolegnia); B, a sporangium of Saprolegnia about to open; C, a single zoospore; D, part of a plant of Saprolegnia with two young oogonia, og; E, a Stock Photo](https://c8.alamy.com/comp/REXDAT/lectures-on-the-evolution-of-plants-botany-plants-82-evolution-of-plants-the-fungi-known-as-white-rusts-and-mildews-of-the-latter-the-potato-fungus-phytophthora-infestans-the-cause-of-the-destructive-quot-potato-rotquot-is-one-of-the-most-familiar-the-water-moulds-saprolegniaceae-fig-21-a-d-are-aquatic-fungi-either-saprophytes-on-the-dead-bodies-fig-21-phycomycetes-a-a-dead-fly-covered-with-a-growth-of-water-mould-saprolegnia-b-a-sporangium-of-saprolegnia-about-to-open-c-a-single-zoospore-d-part-of-a-plant-of-saprolegnia-with-two-young-oogonia-og-e-a-REXDAT.jpg ". Lectures on the evolution of plants. Botany; Plants. 82 EVOLUTION OF PLANTS the fungi known as white-rusts and mildews. Of the latter the potato-fungus, Phytophthora infestans, the cause of the destructive " potato-rot," is one of the most familiar. The water-moulds (Saprolegniaceae), (Fig. 21, A, D) are aquatic fungi, either saprophytes on the dead bodies. Fig. 21 (Phycomycetes). — A, a dead fly covered with a growth of water- mould (Saprolegnia); B, a sporangium of Saprolegnia about to open; C, a single zoospore; D, part of a plant of Saprolegnia with two young oogonia, og; E, a Stock Photo")
RMREXDAT–. Lectures on the evolution of plants. Botany; Plants. 82 EVOLUTION OF PLANTS the fungi known as white-rusts and mildews. Of the latter the potato-fungus, Phytophthora infestans, the cause of the destructive " potato-rot," is one of the most familiar. The water-moulds (Saprolegniaceae), (Fig. 21, A, D) are aquatic fungi, either saprophytes on the dead bodies. Fig. 21 (Phycomycetes). — A, a dead fly covered with a growth of water- mould (Saprolegnia); B, a sporangium of Saprolegnia about to open; C, a single zoospore; D, part of a plant of Saprolegnia with two young oogonia, og; E, a
RMRDHNX0–. Elements of plant biology. Plant physiology. POTATO BLIGHT 177 most favourable to the spread of the fungus, for in such conditions the conidia are formed, scattered by the wind, and germinate, with the greatest rapidity.. Fig. 18.—Conidia and zoospores of Potato Blight [Phytophthora infestans). A, conidium cut off from the end of a hypha. X 500. B, conidium evacuating zoospores, x 500. C. two zoospores. x 500. D, zoospore germinating. E, branched conidiophore. The conidia have fallen from the tips of three branches, one is shown free and one still attached. The branch on the right Is just fo
RMRDE4Y7–. The fungi which cause plant disease . Plant diseases; Fungi. Fia. 416.—Sporodesmium antiquum. After Sac- caxdo. S. exitiosum var. solani Schenck is reported as the cause of a potato disease. S. solani-varians Yanha is the cause of potato disease in Europe, the foliage bearing brown spots and finally dying in a manner resembling death caused by Phytophthora. Cladosporium and pycnidial forms are said to exist. S. mucosum Sacc. was reported by Ader- holt on cucumber fruit and leaves causing disease. S. scorzonerae Aderh. causes a salsify stem and leaf disease.'^* Other parasitic species are: S.
RMRE2MY4–. Elementary botany. Botany. FUNGI CONTINUED: CLASSIFICATION. 215 ant blight (Phytophthora), the white rust of cruciferous plants (Cystopus = Albugo), the damping-off fungus (P-thium), and man^â parasites of the dlgce known as chytrids, as OlpicHum, Rhizophiflium, Lagenidium, Chytri- diuni, etc. The two following orders are sometimes placed in a separate subclass, Archimycetes. 433. Order Chytridiales (Chytridinese).âThese include the lowest fungi. Many of them arc parasitic on alg;c and lack mycelium, the s^^â arm spore either with or without minute rhi^oids, developing into a globose sporan
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
![. Lectures on the evolution of plants. Botany; Plants. 82 EVOLUTION OF PLANTS the fungi known as white-rusts and mildews. Of the latter the potato-fungus, Phytophthora infestans, the cause of the destructive " potato-rot," is one of the most familiar. The water-moulds (Saprolegniacese), (Fig. 21, A, D) are aquatic fungi, either saprophytes on the dead hodies. Fig. 21 (Phycomyoetes). — A, a dead fly covered with a growth of water- mould (Saprolegnia); 6, a sporangium of Saprolegnia about to open; C, a single zoospore; D, part of a plant of Saprolegnia with two young oogonia, og; E, a Stock Photo](https://c8.alamy.com/comp/RDGW87/lectures-on-the-evolution-of-plants-botany-plants-82-evolution-of-plants-the-fungi-known-as-white-rusts-and-mildews-of-the-latter-the-potato-fungus-phytophthora-infestans-the-cause-of-the-destructive-quot-potato-rotquot-is-one-of-the-most-familiar-the-water-moulds-saprolegniacese-fig-21-a-d-are-aquatic-fungi-either-saprophytes-on-the-dead-hodies-fig-21-phycomyoetes-a-a-dead-fly-covered-with-a-growth-of-water-mould-saprolegnia-6-a-sporangium-of-saprolegnia-about-to-open-c-a-single-zoospore-d-part-of-a-plant-of-saprolegnia-with-two-young-oogonia-og-e-a-RDGW87.jpg ". Lectures on the evolution of plants. Botany; Plants. 82 EVOLUTION OF PLANTS the fungi known as white-rusts and mildews. Of the latter the potato-fungus, Phytophthora infestans, the cause of the destructive " potato-rot," is one of the most familiar. The water-moulds (Saprolegniacese), (Fig. 21, A, D) are aquatic fungi, either saprophytes on the dead hodies. Fig. 21 (Phycomyoetes). — A, a dead fly covered with a growth of water- mould (Saprolegnia); 6, a sporangium of Saprolegnia about to open; C, a single zoospore; D, part of a plant of Saprolegnia with two young oogonia, og; E, a Stock Photo")
RMRDGW87–. Lectures on the evolution of plants. Botany; Plants. 82 EVOLUTION OF PLANTS the fungi known as white-rusts and mildews. Of the latter the potato-fungus, Phytophthora infestans, the cause of the destructive " potato-rot," is one of the most familiar. The water-moulds (Saprolegniacese), (Fig. 21, A, D) are aquatic fungi, either saprophytes on the dead hodies. Fig. 21 (Phycomyoetes). — A, a dead fly covered with a growth of water- mould (Saprolegnia); 6, a sporangium of Saprolegnia about to open; C, a single zoospore; D, part of a plant of Saprolegnia with two young oogonia, og; E, a
RMRDD1JR–. Comparative morphology and biology of the fungi, mycetozoa and bacteria . Plant morphology; Fungi; Myxomycetes; Bacteriology. Frc. 64. Phytophthora infestans. Eiti«imties*of two simple sporophores. (zfor. marion of the first gonidia on the tip of each branch, b two ripe gonidia on each branch, a third beginning to form. Magn. about 200 times.. Fig. 65. Phytophthara infestatts. a sporangium in water after the division is completed, b escape of the ten swarm-spores from the sporangium, c spores in the motile state, rf spores come to rest and beginning to germinate. Magn. 390 times.. Please not
RMRDDWNB–. Diseases of plants induced by cryptogamic parasites : introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae . Plant diseases; Parasitic plants; Fungi. PHYTOPHTHORA. 121. Fig. 32.—Pkytopkthora infestans. The Potato disease. A, Potato leaf with brown spots and white patches of fuDgi on the lower side. £, Groups of conidio- phores emerging from a stoma close beside a hair of the potato leaf. C, Conidio- phores and conidia, much enlarged. B, Leaf of potato much shrivelled up and brown, as in the later stages of the disea-se. (y. Tubeuf del.). Please note that these im
RMRDD1NE–. Comparative morphology and biology of the fungi, mycetozoa and bacteria . Plant morphology; Fungi; Myxomycetes; Bacteriology. Fig. S3. Phytophthora infestans, Mont, a a sporangium lying in water alter the division is complete, b escape of the lo swarm- spores from the sporangium. £-spores in the motile state, rf spores at rest and beginning to germinate. Magn. 390 times. Fig. 54. Cladochytrium Iridis. a resting- spore with a brown membrane seen from the broad side, b the same rotated through 90°, in the centre is a large fatty spherical body. c-€ successive stages of germination of a single
RMRDG54X–. Essentials of botany. Botany; Botany. THE FUNGI 249 (Sect. 315). The zygospore formation of bread-mold consid- erably resembles the mode of spore production in Spirogyra (Sect. 282), but the mold gametes contain many nuclei.. Fig. 174. Spore-Formation in Potato-Blight {Phytophthora infestaris), one of tHe algal fungi. A, a well-developed group of stalks, proceeding from a mass of mycelium inside the leaf and escaping through a stoma; B, a young, unbranched stalk, h, hyphae of mycehum; o, stoma; s, spore. (Both figures greatly magnified, S more than A.) It appears highly probable that such al
RMRDE4YA–. The fungi which cause plant disease . Plant diseases; Fungi. THE FUNGI WHICH CAUSE PLANT DISEASE 617. Fia. 416.—Sporodesmium antiquum. After Sac- caxdo. S. exitiosum var. solani Schenck is reported as the cause of a potato disease. S. solani-varians Yanha is the cause of potato disease in Europe, the foliage bearing brown spots and finally dying in a manner resembling death caused by Phytophthora. Cladosporium and pycnidial forms are said to exist. S. mucosum Sacc. was reported by Ader- holt on cucumber fruit and leaves causing disease. S. scorzonerae Aderh. causes a salsify stem and leaf di
RMRDWFM6–. Essentials of botany. Botany; Botany. THE FUNGI 249 (Sect. 315). The zygospore formation of bread-mold consid- erably resembles the mode of spore production in Spirogyra (Sect. 282), but the mold gametes contain many nuclei.. Fig. 174. Spore-Formation in Potato-Blight {Phytophthora infestans), one of the algal fungi. A, a well-developed group of stalks, proceeding from a mass of mycelium inside the leaf and escaping through a stoma; -B, a young, unbranched stalk, h, hyphse of mycelium; o, stoma; s, spore. (Both figures greatly magnified, B more than A.) It appears highly probable that such a
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