INTEGRATED MANAGEMENT OF PAPAYA RING SPOT VIRUS (PRSV) IN AGRO ECOLOGICAL CONDITIONS OF BIHAR

Abstract

Over the last decade Papaya ring spot virus (PRSV) has been identified as a major threat of papaya production resulting in heavy reduction in area under this crop. In an attempt to combat the disease, a field trial was conducted to manage PRSV through integrated approach. Seven treatments viz. 1. Raising of papaya seedlings under Nylon net (40-60 mesh) and spraying of Dimethoate (1.05%) 3 days before planting; 2. Use of two rows of maize as a border crop (Maize sown 15 days ahead of planting); 3. Application of neem seed kernel extract (2%) at 15 days interval (30 days after planting); 4. Application of Dimethoate (1.05%); 5. Application of neem oil 1% + Dimethoate (1.05%); 6. Two rows of maize as a border crop + application of Zn (0.5%) and B (0.1%); and 7. Control without any treatment was evaluated in randomised block design (RBD) with 12 plants/treatment with spacing of 1.8×1.8 m/plant during 2005-2006 and 2006-07. All the treatments were replicated thrice. Observation on PRSV incidence was recorded starting from 60 to 210 days after planting (DAP) at monthly interval. Initially at 60 to 150 DAP there were significant differences among various treatments in relation to their effect on the incidence of PRSV. The most effective treatment was application of neem oil 1 % + Dimethoate 1.05% with least disease incidence (6.66%) and 41.66% respectively at 60 and 150 DAP. This was followed by application of Dimethoate 1.05% with 16.33 and 56.66% PRSV incidence while the untreated (control) plants registered 68.33 and 90% incidence respectively at 60 and 150 DAP. But after 210 days all the treatments were at par in relation to their effect on disease. However the treatment comprising of neem oil 1 % + Dimethoate 1.05% showed the minimum disease incidence (76.66%) as compared to the control showing 100% incidence at 210 DAP. Growth and yield characters of papaya i.e. plant height at first flowering, plant height at first harvest, stem girth at harvest and number of fruits were significantly affected by the treatments while mean fruit weight was not affected markedly. Likewise some quality parameters of fruits i.e. TSS and central cavity diameter did not show notable difference due to the treatments although other quality parameters like average fruit weight, fruit length, fruit diameter and hundred seeds weight were appreciably affected by the treatments.