Stage-specific mortality of Spodoptera litura and Etiella zinckenella in summer soybean

Abstract

Soybean ( Glycine max (L.) Merrill) is an important oilseed legume that aids food security and soil fertility. In the Marathwada region, farmers cultivate soybean during the offseason summer months for seed production; however, its productivity is affected by major pests such as Spodoptera litura and Etiella zinckenella. The present investigation was conducted at the Research Farm, Department of Entomology, College of Agriculture, Latur, Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani during summer 2021-22 to prepare field life tables and identify key mortality factors. Observations were recorded weekly under unsprayed conditions. In Spodoptra litura, early instar mortality was 12.45 and 14.23 per cent due to Spodoptera litura nuclier polyhydrosis virus and Chelonus formosanus, respectively, with generation survival of 0.75 and total K value of 0.4253. In E. zinckenella, larval mortality due to predation, adverse climatic condition, and parasitization by Bracon onukii ranged from 2.23 to 5.30 per cent, with generation survival of 0.85 and total K value of 0.3708. Early instars were the most important for mortality, suggesting their significance in pest management.