Seasonal incidence of major lepidopteran pests in soybean (Glycine max L. Merrill) with relation to weather parameters

The investigation on “Seasonal Incidence of Major Lepidopteran Pests in Soybean (Glycine max L. Merrill) with relation to weather parameters” was conducted at Instructional Farm and Department of Entomology, Rajasthan College of Agriculture, Udaipur during Kharif, 2023. The study reveals that Tobacco caterpillar (Spodoptera litura), Green semilooper (Chrysodeixis acuta), Leaf miner (Aproaerema modicella) and Pod borer (Helicoverpa armigera) were recorded as major insect pests of Soybean crop at Udaipur conditions. The peak population of S. litura (3.20 larvae per plant), C. acuta (2.00 larvae per plant) and H. armigera (3.00 larvae per plant) were recorded during last week of August (35th Standard Meteorological Week, SMW) whereas, the peak population of A. modicella (3.00 larvae per plant) was recorded during third week of August (33th SMW). The weather parameters, the morning relative humidity and number of rainy days had significant negative correlation with the peak population of S. litura (-0.727 and -0.520), C. acuta (-0.614 and -0.668) and H. armigera (-0.576 and -0.562), respectively whereas, evening relative humidity had significant negative correlation only with S. litura (-0.590) and H. armigera (-0.532) and non significant correlation with C. acuta (-0.402). The evaporation had significant positive correlation with S.litura (0.549), C. acuta (0.657) and non significant positive correlation with H. armigera (0.449). The peak population of A. modicella exhibited significant negative correlation with morning relative humidity (-0.501) and number of rainy days (-0.648) while, wind velocity (0.684) and evaporation (0.632) showed significant positive correlation.