Epidemiology and Management of Grain Discoloration in Paddy

Abstract

newline Extensive surveys were conducted to ascertain the prevalence and extent of grain discoloration and fungi associated with the disease on paddy inJammu Division, viz., Jammu, Samba and Kathua districts during Kharif2021 and 2022. Maximum disease incidence was recorded in villageRangapurMaulania (29.98%) of R. S. Pura block inJammu district and minimum in village Sultan Pura (18.59%)inKathua district. Paddy samples collected during surveys were examined through blotter and PDA plate methods and eight fungi viz., Bipolarisoryzae, Pyriculariaoryzae, Dreschleraoryzae, Curvularialunata, Alternariaalternata, Fusariummoniliforme, Nigrosporaoryzae and Sarocladiumoryzaewere found associated with grain discoloration. Highest frequency of mycoflora was found in PDA plate method. Among these isolated fungi, B. oryzae,C. lunata, A. alternataand F. moniliformewere f predominant in all rice cultivars.Twelve fungi were isolatedfrom discolored stored rice grains using PDA plate method and identified as B.oryzae, P.oryzae, D.oryzae, C.lunata, A.alternata, F. moniliforme, N.oryzae, S.oryzae, Aspergillusspp., Pencilliumspp., Trichotheciumspp. and Rhizopusstoloniferunder storage conditions. Two groups of fungi were associated with grain discoloration of rice. One group comprised of field fungi viz., B. oryzae, P. oryzae, D. oryzae, C. lunata, A. alternata, F. moniliforme, N. oryzaeand S. oryzaethat infected grain before harvest. Another group comprised of storage fungiviz., Aspergillus sp., Penicillium sp., Rhizopusstolonifer and Trichothecium spp. that infectedrice grains after harvest.Artificial inoculation of individual fungiviz., C. lunata, P. oryzae, F. moniliforme, B. oryzae, A. alternata, D. oryzae, S. oryzae and N. oryzaeat different stages (viz., booting, heading, milking and dough) of rice plant growth and found maximum discoloration at heading stage followed by booting, milking and dough stages. Epidemiological studies revealed that initial disease symptoms were observed in second week of September and highes