Assessing the influence of sowing dates and crop geometry on Fall Armyworm infestation in maize (Zea mays L.)

Abstract

The present investigation to determine the effect of date of sowing and crop geometry against fall armyworm (FAW) damage in maize was conducted in TNAU, Coimbatore during the Summer and Rainy seasons using three different crop geometries as precision farming (75 × 25 cm), TNAU recommended spacing (60 × 25 cm) and farmer's practice (45 × 25 cm) in three sowing windows. Among sowing windows, the crop grown in 12th standard meteorological week (SMW) was associated with the highest levels of leaf damage of 11.16 , 71.0 , and 50.71 per cent recorded at 16, 30, and 60 days after sowing (DAS), whereas the crop sown in 7th SMW experienced the least damage (8.32% at 16 DAS, 23.01% at 30 DAS, 31.71% at 45 DAS, and 22.96% at 60 DAS) and the intermediate damage occurred in 9th SMW in the summer season. Contrarily, during the rainy season, the highest leaf damage occurred in crop sown at 34th SMW (26.20 , 46.87 and 30.0 per cent at 30, 45, and 60 DAS, respectively) and the lowest leaf damage of 3.50, 13.01, 27.34 and 17.83 per cent recorded at 16, 30, 45 and 60 DAS, respectively for 39th SMW sown crop. The 37th SMW sown crop exhibited intermediary damage. Among the altered cropping geometries wider spacing (75 × 25 cm) between rows has lesser leaf damage in contrast, dense arrangement (45 × 25 cm) created a favourable microclimate for fall armyworm infestation and 60 × 25 cm has an intermediary infestation with the highest grain yield among the cropping geometries. So, the planting geometry 60×25 cm may be adopted as one of the cultural practices in the integrated pest management of maize considering both yields as well as FAW damage.