Effects of long-term tillage and residue management practices on pest infestation in rabi maize in maize-maize-Sesbania system

Abstract

Conservation agriculture based crop management of no tillage and residue retention found to be resource efficient, productive and remunerative in maize based cropping system in India (Parihar et al., 2016). Understanding the dynamics of key pests in varying tillage and residue management practices will help to custom design system based sustainable crop protection practices. In India, major pests of maize are spotted stem borer (Chilo partellus Swinhoe) in kharif, pink stem borer (Sesamia inferens Walker) in rabi and shoot fly (Atherigona spp.) in spring seasons. Fall armyworm (FAW) (Spodoptera frugiperda J. E. Smith), which invaded India in 2018 was found to damage both kharif and rabi maize. Effect of tillage practices [permanent beds with residue (PB), zero tillage (ZT) and conventional tillage (CT)] on infestation S. inferens in maize-maize-Sesbania system was studied in a long term experiment going on at fixed site since 2008. Infestation of S. inferens was identified by the sudden wilting and/or dying of the central whorl called ‘dead heart’ in V3-V6 stage maize plants, recorded during rabi seasons of 2017-18, 2018-19 and 2019-20 (up to December 2019). The highest percentage infestation of S. inferens was observed in PB (10.4 to 26.1 %), followed by ZT (5.7 to 20.2 %) and least in CT (4.8 to 6.2 %), with significant differences over the years. In 2020, heavy infestation of FAW was also observed as high as 99.5% in CTand the least in ZT (84.19%). Severity of damage in terms of Davis score 1􀀐9 (Davis and Williams, 1992) was assessed, where least severity was observed in ZT and highest in CT. However, CT recorded low survival of FAW and high recovery of plants in subsequent observations. Since FAW feeds on plant whorl, while S. inferens infests the base, system needs to be observed closely in the coming years.