Environmental factors influencing the population of whitefly and leaf curl disease incidence in chilli

Aim : Chilli (Capsicum annum) is an important spice crop cultivated all over the world. The importance of chilli leaf curl disease has been recognized for many years because it is one of the most devastating disease in chilli growing area and transmited through the vector whitefly (Bemisia tabaci Genn) under favorable environmental conditions. The present study was conducted to study the effect of meteorological factors on whitefly population and incidence of chilli leaf curl virus disease. Methodology : A rectangular cage was formed by ply wood and fiber glass. The ply wood plate was cut according to required size and made in rectangular form. Randomly selected five plants of each plot in rectangular cage were observed population of white fly and disease intensity of leaf curl virus at weekly interval starting from 20 days after transplanting at the morning hours (6-7 a.m.) on the defined day. Meteorological data viz., maximum temperature, minimum temperature, relative humidity, total rain fall and wind velocity were obtained from the meteorological observatory, Narendra Dev University of Agriculture and Technology, Faizabad. Results : The first appearance of white fly was recorded on 10 standard week and rapid progress of white fly population was recorded from 11 standard week to 17 standard weeks in 2014 and 18 week in 2015. The increase in white fly population was positively correlated with minimum and maximum temperature. Disease incidence of chilli leaf curl virus was significant and positively correlated with white fly population (r=0.93 in 2014 and r=0.89 in 2015). The maximum percent leaf curl increase was observed on 19 standard week when white fly population was highest in the field. Interpretation : The increase or decrease of leaf curl virus disease of chilli was directly correlated with vector population and vector population was determined by environmental factors. It is concluded that whitefly population and leaf curl incidence increased with increasing the temperature, as well as relative humidity and decreased with the occurrence of rainfall.