Influence of ambient weather on the incidence of major insect pests and their bioagents of soybean crop (Glycine max L. Merrill)

Abstract

Investigations were carried out during Kharif , 2012 at Indira Gandhi Krishi Vishwavidyalaya, Raipur (C.G.) on, the effect of different weather parameters on seasonal incidence of girdle beetle, lepidopterous caterpillars and sucking pests was observed. In this context, the peak activity of the girdle beetle was noticed during the first week of October which was associated with 31.9°C maximum temperature, 23.9°C minimum temperature, 91 per cent morning R.H., 56 per cent evening humidity, 9.2 mm rainfall and Sunshine hours 7.6 lux. The peak activity of total caterpillar pests ( S. litura, C. acuta and H. armigera ) was observed during third week of August with 30.2°C maximum temperature, 25.3°C minimumtemperature, morning and evening R.H. 90per cent and 78 per cent, a rainfall of 33.2 mm, respectively and sunshine hours 3.5 lux. The peak density of total sucking pests was observed during third week of August which was associated with 28.8°C maximum temperature, 24.8°C minimum temperature, morning and evening R.H. 93 per cent and 79 per cent, rainfall 106.8 mm, respectively, and sunshine hours 1.3 lux. The correlation coefficient between the predatory population and different weather parameters viz. , maximum and minimum temperatures, morning and evening R.H., rainfall and sunshine hours was worked out and found to be nonsignificant.