Seasonal incidence of fruit borer, Helicoverpa armigera (Hub.) in tomato in relation to weather parameters

Abstract

A field experiment was conducted at farm of Agricultural Research station, Swami Keshwan and
Rajasthan Agricultural University, Bikaner, during the 2013-14, rabi season, to study seasonal
incidence of tomato fruit borer, Helicoverpa armigera. Tomato fruit borer, H. armigera is a well known
polyphagous insect. The larvae feed on the leaves and bore into fruits, thereby causing severe damage
to the crop and significant losses in yield. Besides tomato, it is a regular pest of chickpea and cotton.
The incidence of fruit borer started in the last week of December on tomato. The population lowered
down upto 3rd SMW (Standard Meteorological Week) and thereafter, population increased but
fluctuating trend was recorded upto 9th SMW. The larval population increased and reached to peak
in 12th SMW. Thereafter, it's population decreased gradually and negligible population was recorded
upto second week of April. A significant positive correlation was observed between pest population
and maximum and minimum temperature, whereas, it was non-significant positive with average
relative humidity. A non-significant negative correlation was computed between pest population
and total rainfall.