Field experiment was conducted in 2013 and 2014 cropping seasons at the Teaching and Research Farm of the Federal University of Agriculture Makurdi, Benue State of Nigeria to Assess the incidence of early and late leaf spot disease infection induced by (Cercospora arachicola Hori) and (Phaeoisariopsis persanata [Berk and Curt]) and agronomic performance of some selected groundnuts cultivars in Makurdi, Benue State of Nigeria. These selected groundnut cultivars (treatments) include: Ex-Dakar, Danbomboyo, Borno Brown, Samnut-10, Borno Red, Benue-AGR, Shar-nya, Aloshi, Samnut-22, Tisha-1, Ijiwanda, Sannut-21 and Campalla. The treatments were replicated four times and laid in a randomized complete block design (RCBD). The land and ridges were prepared manually using hoes. The seeds were sown by dibbling per hole on top of four ridges per a plot, each measuring 3 x 2m. Results revealed significant difference (P≤ 0.05) on incidences of early and late leaf spot disease, plant height (cm), ...

Background: Early leaf spot caused by Cercospora arachidicola Hori. is most destructive disease in all the groundnut growing areas of Rajasthan, under severe infestation it cause 30-50% losses in pod yield. Recently, Central Insecticide Board (CIB), Faridabade banned 27 pesticides including some important fungicides which are extensively used in plant disease management. Therefore, in the present investigation, our main emphasis was to find out some new fungicides for management of early leaf spot disease. Methods: Ten fungicides (hexaconazole 5% EC, difenconazole 25% EC, propiconazole 25% EC, tebuconazole 25.9% EC, trifloxystrobin 25% + tebuconazole 50% WG, mancozeb 50% W P, chlorothalonil 75% WP, carbendazim 50% W P, carbendazim 12% + mancozeb 63% W P and captan 70% + hexaconazole 5% W P) were evaluated against early leaf spot pathogen (C. arachidicola) both in lab as well as in field condition. The experiment was conducted at ARS, SKRAU, Bikaner during Kharif-2019 on most popular cv. HNG-69 in RBD design with the application of foliar spray of ten different fungicides at different concentrations against early leaf spot disease and compared with an untreated control. Result: Among all the fungicides used in the present investigation, Tebuconazole 25.9% EC was found most effective in inhibiting the mycelial growth of the pathogen followed by trifloxystrobin 25% + tebuconazole 50% W G. Under field condition, it gave maximum (70.73%) disease control with highest pod yield (31.5 q/ha) and net return (Rs 57,500/ha) when applied as foliar spray at 0.1% concentration followed by trifloxystrobin 25% + tebuconazole 50% W G at 0.2%. These treatments can provide an effective and economical management of early leaf spot disease for groundnut cultivators.

Early leaf spot disease in groundnut is prevalent in all growing seasons but it is rampant during Kharif season. Due to favourable climatic conditions for spore germination weather parameters are found to influence the development of disease significantly. Successful initiation as well as spread of disease requires virulent inoculums, susceptible host and most importantly a conducive environment. Weather parameters affect every step of infection process starting from propagule germination, penetration of germ tube and host colonization. Study conducted at Orissa University of Agriculture and Technology reveal a positive correlation of the disease with weather parameters like T max , T min , afternoon relative humidity, rainy days and evaporation. A regression analysis of the data inferred that the weather parameters as a whole contribute about 87.03% to the incidence of disease, of these evaporation and rainy days contributed 51.22% and 29.87% respectively. Afternoon relative humidi...

Background: Groundnut (Arachis hypogaea L.) is the fourth most important oil seed crop in the world. The early and late spots are a foliage disease more common and more destructive of groundnut which cause severe yield losses up to 70% and reduces the quality of the pod and fodder. Recent efforts have targeted on developing resistant source against leaf spot disease which are helpful for discarding the hazardous toxic chemical compounds used for controlling the disease. The current study aimed to identify the sources of resistance to leaf spot from the newly identified genotypes as well as from wild species and to study the way in which these were responding to the to the disease development. Methods: Seventy three groundnut genotypes were screened against late leaf spot disease under artificial epiphytotic conditions in field at AICRP on Groundnut, MPKV, Rahuri during kharif 2015-16. The observations of disease intensity and rate of infection were recorded. Result: Among the Seventy three groundnut genotypes, 10 genotypes showed resistant and 33 genotypes showed the moderately resistant reaction to leaf spot disease. The 25 entries showed the susceptible and 05 genotypes showed the highly susceptible reaction to the leaf spot disease. All the susceptible cultivars belong to A. hypogaea sub. sp. fastigiata var. fastigiata to as Spanish bunch. These 10 resistant genotypes of groundnut including two wild species viz.,

A Thesis submitted in partial fulfillment of the requirements for the a ward of the degree of Master of Science in crop science of Makerere University