Influence of Abiotic Factors on Pheromone Trap Catches and Field Infestation of Helicoverpa armigera on Carnation (Dianthus caryophyllus) in Hilly Region of West Bengal, India

Abstract

An experiment was carried out at Regional Research Station, Uttar Banga Krishi Viswavidyalaya, Kalimpong, during the winter seasons of 2008-09 and 2009-10, to study the impact of weather factors on pheromone trap catches and field infestation of Helicoverpa armigera (Hubner) on carnation (Dianthus caryophyllus Linnaeus). Various abiotic parameters like maximum and minimum temperature, maximum and minimum relative humidity and rainfall registered low level of non-significant association with the trap catch data during both the seasons. The simple regression equations of pheromone trap catch data with the meteorological parameters indicated that the abiotic factors had non-significant influence on the trap catches of H. armigera moths. The maximum temperature and rainfall was responsible for the maximum 26.82 and 8.79% variation in the trap catch data during 2008-09 and 2009-10, respectively.The multiple regression analysis showed that the combined effect of all the meteorological parameters was also statistically non-significant, though 62.88 and 69.13% variation in trap catches was due to weather factors, during 2008-09 and 2009-10, respectively. The correlation coefficients (r) between the field infestation data (number of eggs and larvae plant^-1, % bud infestation) and various meteorological parameters revealed that the ecological factors mostly registered non-significant correlation with the field incidence of the pest as well as with the actual infestation of buds and flowers of carnation. Only the minimum temperature was positively and significantly associated with the % bud infestation during both the years.