Influence of weather parameters on the population dynamics of black bug, (Cavelerius sweeti Slater & Mugomoto) in sugarcane in Haryana, India

In autumn planted, sugarcane, (Saccharum officinarum) crop the correlation coefficient showed non significant but positive trend with minimum and maximum temperature. The effect of minimum and maximum relative humidity with black bug population showed a negative correlation. In ratoon crop the highest black bug population 7.2/tiller was recorded during the 4^th week of May at minimum temperature, maximum temperature, minimum relative humidity, maximum relative humidity, 22.9°C 40.9°C 32.0% 46.0% and 9.4 sun shine hours respectively. The Cavelerius sweeti population was significant and positively correlated with minimum and maximum temperature. While minimum and maximum relative humidity was correlated negatively the population of black bug but it was positively correlated with sun shine hours. The regression coefficient for minimum and maximum temperature, minimum and maximum relative humidity and sun shine hours were 0.361, -0.162, -0.054, 0.029 and -0.867 in autumn planted crop and 0.014, 0.610, –0.075, 0.644 and -0.989 in ratoon crop of sugarcane, respectively. The ratoon crop of sugarcane was more vulnerable to C. sweeti attack in comparison to autumn planted sugarcane crop. The weather factors viz., minimum and maximum temperate, minimum and maximum relative humidity and sun shine hours were 22.9°C, 40.9°C 32.0 per cent, 46.0 per cent and 9.4 respectively found optimum for the fast multiplication of the black bug population as well as infestation in ratoon crops.