Impact of weather parameters on insect pest infestation in cauliflower (Brassica oleracea var botrytis L.) seed crop in mid hill regions of Himachal Pradesh

Abstract

Cauliflower is one of the commercial vegetable crop of district Solan. The activity of different insect pest infestation on seed crop was studied at three locations viz., Nauni, Saproon and Kandaghat in Solan district of Himachal Pradesh during 2014-15 and 2015-16. During the growth period different insect pest were cabbage aphid (Brevicoryne brassicae), cabbage caterpillar (Pieris brassicae) and painted bug (Bagrada hilaris) at all the locations under study. The relationship between weather parameters and pest population was worked out by correlation analysis. The pest populations were influenced by weather parameters, mainly maximum, minimum temperature and humidity (forenoon and afternoon). The highest number of insect pests were recorded at Nauni, followed by Kandaghat and lowest were recorded at Saproon. Among different insect pest aphids were most frequent in occurrence and had a significant negative correlation with maximum temperature at Nauni and Kandaghat (r=-0.864, r=-0.722), respectively. In Saproon and Nauni, cabbage aphid population also had significant positive correlation with forenoon humidity (r = 0.821) and r = 0.696). Cabbage caterpillars though had negative correlation with maximum temperature at Saproon but it was non-significant while it was significant at Nauni and Kandaghat (r = -0.742 and r = -0.713). Similarly pest population showed positive correlation with forenoon humidity with significant effect at Saproon (r=0.919). Painted bug population exhibited negative effect with forenoon and afternoon humidity at Nauni and Saproon whereas, which was significant while it showed non-significant effect at Kandaghat on population build up.