Indian Journal of Plant Protection

Studies on the influence of weather factors on the population dynamics of hadda beetle, Henosepilachna vigintioctopunctata were undertaken at Entomological Experimental Farm, CSK Himachal Pradesh Agricultural University, Palampur during crop growing seasons of 2009 and 2010. The first incidence of adult beetles was observed during 1^st week (26 SW) of July in 2009. During 2010, the activity of adult beetles was first noticed earlier than 2009 in the 3^rd week (24 SW) of June. The total peak population (grubs, pupae and adults) of 36.9 and 59.7 insects per plant was recorded during 3^rd & 4^th week of August (33 & 34 SW) in 2009 and 2010, respectively. The highest infestation index was found coinciding with the peak total population and highest per cent plant infestation. The studies revealed strong and significant negative correlation of grubs, pupae, adults and total population with maximum temperature and highly significant positive correlation with mean relative humidity and rainfall. Grubs and total population exhibited significant and negative correlation with sunshine hours, while the pupae and adults showed non-significant negative correlation. Minimum temperature showed no significant effect.