PATEL, B. K.PATEL, RAJESH J.2018-05-132018-05-131993http://krishikosh.egranth.ac.in/handle/1/5810045408Ciimin (Cuminum cyminum L.) commonly known as "Zeera" is possibly a native of Egypt. This spice occupies a substantial area amongst the non-food crops grown in the country. Cumin blight and powdery mildew are invariably coming every year and cause tremendous losses in grain yield and quality. Under the field conditions, hrovm to daric brown patches against normal green were visible from a distance in case of blight . In case of powdery mildew small white or greyish specks were found first on lower leaves . Later on entire stirface of the plant was covered up with mycelium and spores of the fungus. Altemaria sp. causing blight was found pathogenic at various crop stages viz., leaves, steiE, branches, flowers and umbels. Among various solid and liquid media studied, potato dextrose agar (PDA) and Richards' medium supported the maximum fungal growth on solid and liquid media respectively , Harvest dry mycelial weight of Altemaria sp. was recorded at pH 6.5 followed by 7.0 on Richards' medium when incubated for 15 days. Lactose served the superior carbon source for the dry mycelial weight followed by sucrose and galactose. Among various nitrogen sources studied, potassium nitrate found as the best nitrogen source in yielding the highest dry mycelial weight of Altemaria sp-;. Pseudomonas spp. as the antagonist showed the maximum inhibition of Altemaria sp. among various antagonists studied. Nuvan (at 150, 300 and 600 ppm) showed the maximum growth inhibition of Altemaria sp. followed by rogor (600 ppm) and ekalux (1000 ppm). Metasystox, hostathion, astaf, nicotin sulphate, padan, neemark and nuvacron increased infective propagules (fungal mass) by accelerating the fungal growth. Like insecticides, known herbicide-metribuzine (sencor) at recommended dose (2000 ppm) as well as one and half of the recommended dose showed the highest growth inhibitory effect on Altemaria sp. Among the various fungicides screened, dithane M-45 completely inhibited the growth (100 percent ) of Altemaria sp. at 1000, 2000 and 3000 ppm concentrations followed by foltaf. Dithane M-45 alone and in combination with Pseudomonas sp. and tridzophos also completely inhibited fungal growth of Altemaria sp. Maximum blight and pov/dery mildew intensity were recorded in 5th date (23rd Nov.'92) of sowing. Maximum grain yield with very low blight and powdery mildew intensity were recorded when the crop was sown on 31st Oct., '92. In 1991-92, minimum per cent disease intensity of altemaria blight, maximum grain and fodder yield were recorded In plots were sprayed thrice with dlthane M-45 @ 0.25 % followed by Azotobacter sp.. In the second year (1992-93), minimum blight Intensity and highest grain and fodder yield were observed in plots sprayed four times with dithane M-45 @ 0.25 % followed by captafol (0.25 per cent). In case of powdery mildew, minimum disease intensity was recorded during rabi 1991-92, in the plots treated with wettable sulphur @ 0.2 per cent followed by metalio sulphur @ 25 kg/ha. Similarly in the year (1992-93), minimum powdery mildew intensity and maximum grain and fodder yield were noted in plots treated with wettable sulphur @ 0.2 per cent followed by triazophos @ 0.02 per cent, callxin @ 0.04 per cent and metalic sulphur @ 25 kg/ha. Existing a l l the cumin varieties/selections viz., GC-1, JC-147, JC-100 and JC-106 were found susceptible to altemaria blight. Cumin variety GC-1 is susceptible at any crop stage before, at and after flower stage. Less sun shine hours (8.73) cloudy conditions for 2-3 days, high humid weather (66,41 per cent and more), trace rainfall and 11.34 to 28.07°C temperature favoured the infection and the spread of the blight during second standard week. Occurance and the spread of powdery mildew was favoured by 9.40 to 28.59°C temperature with 55.52 to 48.70 per cent relative humidity and 9.03 sun shine hours.enPLANT PATHOLOGY, AGRICULTUREA STUDYThesis