Sunflower defoliator population influenced by long term climatic trends and extreme weather conditions

Abstract

An experiment to study incidence of defoliators on sunflower and their relation to weather parameter was carried out in non replicated design during Kharif 2001 to 2012, observations on pest incidence were recorded in the experiment as per the standards, weather parameter recorded in meteorological observatory at oilseeds research station, Latur, were used. Year wise data on pest incidence and weather parameter recorded on weekly basis was averaged for entire period. The weather - pest interaction in sunflower for defoliators was analysed by adopting correlation and regression studies.Results of correlation studies revealed that, overall mean population of defoliators was significant and positively correlated with relative humidity-II. It is also evident from data that mean peak incidence of pest that the population of defoliators was at peak in38th MW. When the mean weather parameters of 37th week were maximum temperature (29.3 0C), minimum temperature (20.25 0C), precipitation (46mm), relative humidity I (81.95%) & humidity II (73.62%). Therefore it can be concluded that increase in relative humidity is causing significant increase in defoliators population and highest population density of the defoliators were observed during 37th SMW which means the weather parameters during this period were most conducive for pest population.