Input-based assessment on integrated pest management for transplanted rice (Oryza sativa) in India

Abstract

Globally, India ranks second in terms of area planted under rice (Oryza sativa) and its production as well. Potential to yield is dented due to a lack of inbuilt resistance to different biotic stresses as discernible in ~1000 rice cultivars across the country. Farmers usually rely on applying pesticides that result in several environmental adversities apart from rejection of export consignments due to the presence of chemical residue in grains. Yield losses due to pests of rice in tropical Asia range 25–43%. There is a need to explore alternative integrated input-based management options for judicious use of chemicals with optimal combinations of non-chemical interventions to improve productivity and profitability of rice culture. Field trials were conducted in split-split plot design at Chinsurah, West Bengal during three consecutive rainy (kharif) seasons (2013-15) in transplanted rice. The exploratory objectives were to assess different interventions for alleviating crop biotic stresses and obtaining precise estimate of grain yield as well as economic advantages, and to devise a cost-effective recommendation on need-based integrated pest management (IPM) in transplanted rice. Green manuring with 45-day old Sesbania crop showed a significant (P < 0.05) reduction in infestation of leaf folder, stem borer, sheath rot, sheath blight, false smut, brown spot and bacterial leaf blight of rice compared to control. Both the herbicide (pretilachlor)-treated and green (Sesbania)-manured plots displayed a significant (P < 0.05) suppression of weeds. The diseases (sheath rot, sheath blight, brown spot) of rice were significantly (P < 0.05) reduced by all the treatments targeted for better crop management as evidenced from the sub-sub plots. Rice diseases were best managed by seed treatment with carbendazim 50% WP @ 1.0 g a.i./kg seed, and the effect was more pronounced when the crop was green manured. Significantly (P < 0.05) higher grain yield of rice was recorded with Sesbania manuring, which was as good (P < 0.05) as pre-emergence application of pretilachlor. The herbicide application provided the highest (2.03) incremental benefit-cost ratio (IBCR) among the main plot treatments. Seed treatment with carbendazim followed by (fb) seed bed application of Pseudomonas fluorescens in combination with green manuring prior to rice transplanting in main field fb sequential sprays of chlorantraniliprole 0.4% GR (20 DAT), chlorantraniliprole 18.5% SC (40 DAT) and validamycin 3% L (50 DAT) on the standing crop provided the highest (5656 kg/ha) grain yield with a lower (2.02) IBCR. Contrastingly, only seed treatment with carbendazim recorded the highest (73.85) IBCR. Lower pest incidence and higher grain yields did not fetch greater economic return as apparent from the current investigation. Considering quantifiable and economic impact of inputs, their need-based usage would be a cost-effective proposition to take care of dominant pests in transplanted rice. No comprehensive investigation made such a target-based IPM of most influential crop pests of rice for realizing higher productivity and profitability.