Impact of abiotic factors on seasonal incidence of leaf eating caterpillar Spodoptera litura Fabricius infesting soybean

Abstract

Investigations on seasonal incidence of leaf eating caterpillar Spodoptera litura fabricius infesting soybean were carried out at at Junagadh Agricultural University, Dhari (Gujarat) during kharif 2021 and 2022. Data showed that the pest activity commenced from first fortnight of July and continued till September end which ranged from 0.5 to 4.5 larvae/plant and reached at peak level up to 4.5 larvae/plant between August and September month. The pest activity decreased after reached at peak level and then disappeared from last week of September. The correlation matrix indicating the highly significant positive relationship between S. litura population and rainfall and rainy days. Significant positive relationship with morning relative humidity and evening relative humidity. While, significant negative correlation between maximum temperature and sunshine hours. While in the multiple linear and partial regression analysis between weather parameter and mean larval population of S.litura indicated that rainfall and rainy days exhibited a positive while, maximum temperature exhibited negative influence.