Seasonal incidence of insect pests on Amaranthus and Palak in Malnad region of Karnataka

Abstract

An investigation was conducted during 2019–20 at the Zonal Agricultural and Horticultural Research Station, Shivamogga, to assess the seasonal incidence of major insect pests of amaranthus and palak and their association with weather parameters. Distinct seasonal trends were observed in pest population dynamics. Tobacco cutworm (Spodoptera litura) reached peak incidence during the second week of August in Kharif and showed positive correlation with rainfall and evening relative humidity, and negative correlation with sunshine hours and minimum temperature. Leaf miner (Liriomyza sp.) incidence was highest during the first week of October in Kharif and the fourth week of January in Rabi, with positive association with temperature and sunshine hours, and negative association with relative humidity and rainfall. Aphid (Aphis craccivora) population peaked during Rabi and was positively correlated with maximum temperature and sunshine hours but negatively correlated with rainfall and relative humidity. The findings highlight the strong influence of seasonal weather factors on pest-buildup and provide a basis for weather-based pest monitoring and timely management strategies.