Seasonal incidence of insect pests on soybean and impact of various abiotic factors on their incidence

Abstract

Field experiment on seasonal incidence of insect pests on soybean and impact of various abiotic factors on their incidence was conducted during kharif season of 2019 on soybean crop at College of Agriculture, Dhule. The present investigation was carried out with an object to study the seasonal incidence of insect pests on soybean and their natural enemies and their correlation with the weather parameters. During seasonal abundance study, the tobacco leaf eating caterpillar reached its peak activity during third week of September (13.67/mrl), where the peak incidence of green semilooper was also noticed in the third week of September (8.67/mrl). The peak infestation of girdle beetle recorded during third week of August (3.40 %). The peak incidence of Aphids recorded during the fourth week of August (18.40/ 5cm twig). The peak incidence of Jassids recorded during the second week of September (6.40/3 leaves). The peak incidence of White flies recorded during the fourth week of August (2.20/3 leaves). The activity of predator cocconelid beetle was its peak during fourth week of August (3.33/plant). However, the correlation between incidence of tobacco caterpillar, green semilooper, girdle beetle, aphids, jassids, white flies and coccinellid predators were negatively non-significant correlation with minimum temperature and wind speed while maximum temperature, morning and evening relative humidity showed positively non-significant correlation. The correlation between incidence of tobacco caterpillar, green semilooper, girdle beetle, aphids, jassids, white flies and coccinellid predators were positively significant correlation with rainfall, rainy days and evaporation while significantly negative correlation with sunshine hours.