Impact of abiotic factors on seasonal incidence of insect pests of soybean

Abstract

The study was carried out at Agricultural Research Station- Banswara during kharif-2012 and 2013. During the years 2012 and 2013, the peak population of white fly was observed in the 35th SMW and 37th SMW, respectively. The population of whitefly had a positive correlation with the maximum temperature and sunshine (hours) while, negative correlation with rain fall and morning and evening relative humidity during both the years but significant only during 2013. The maximum population of semilooper was recorded in the 36th SMW and 39th SMW, respectively. The semilooper exhibited a significant and positive correlation with minimum temperature, morning evening humidity and rain fall during both the years. The highest girdle beetle damage was recorded in the 35th SMW and 37th SMW, respectively; whereas the maximum incidence of gram pod borer was recorded in the 36th SMW and 39th SMW, respectively. The larval population of gram pod borer exhibited a significant negative correlation with sun shine and minimum temperature during experimental period; whereas, it exhibited a significant and positive correlation with rainfall and relative humidity during both the years. The maximum incidence of tobacco caterpillar in soybean crop was recorded during 41st SMW and 42nd SMW, respectively. The maximum temperature and sun shine hours showed a significant positive correlation with the larval population of tobacco caterpillar while, significant negative correlation with rainfall during both the years. The regression equation indicated that rainfall had significant negative and positive impact on population of white fly and semilooper, respectively. Whereas, maximum temperature had significant positive impact on population of tobacco caterpillar while rainfall had significant negative effect.