Impact of degree-day summation on infestation of gall insect, Pauropsylla beesoni Laing on soalu, Litsea monopetala Roxb., the primary host plant of muga silkworm, Antheraea assamensis Westwood

To study the seasonal variation and growing degree day, data on gall insect, Pauropsylla beesoni Laing population were collected from infested soalu plant grown in experimental field of CMER&TI, Lahdoigarh during 2016–18. The population dynamics of gall insect was calculated by taking year-round population variation from March 2017 to February 2018 while the growing degree day (GDD) was calculated from 1^st March to 31^st July in both the seasons of the same corresponding years. The linear regression analysis between different weather parameters and gall insect population were found to be positively significant in case of maximum temperature (75.83%), minimum temperature (68.44%), minimum relative humidity (68.07%) and total rainfall (82.12%). Further linear regression analysis between GDD and gall insect population during the single life cycle showed an impact of 76 per cent, inferring an effective role of GDD on P. beesoni population.