Outbreak of Spodoptera mauritia Boisduval in Assam Sarma A.K.*, Salam Abdush Krishi Vigyan Kendra, Assam Agricultural University, Dibrugarh, 786010, Assam *Email: ak_barbhagia@rediffmail.com
Online published on 5 February, 2019. Abstract The recent outbreak of Rice Swarming Caterpillar (RSC) during kharif 2016 in Assam is one of the most devastating ever experienced in the state over >34, 650 ha of rice across 28 districts. The outbreak was more severe in areas with monoculture of rice as found in Upper Brahmaputra Valley Zone with 7016 ha in Dibrugarh district alone. Severe deficit (>50%) of rainfall during September, 2015-March, 2016 followed by 40% excess and moderately deficit (>25%) rainfall during April-May and June-August, respectively were observed to be behind the outbreak. Rainfall analysis confirmed that spells of “drought followed by heavy rains” prevailed for about twelve months before favoured the outbreak. Early flood is yet another associated factor that helped in disseminating the caterpillars to new areas and magnified its severity. One “perennial hub of RSC” comprising of several flood prone villages has also been identified in the district. Identifying more of such hubs and their microecological study might help in prediction of outbreak with accuracy. Top Keywords Outbreak, Spodoptera mauritia, rice, Assam, Upper Brahmaputra valley, Dibrugarh, rainfall, drought, flood, ecology. Top |