Impact of abiotic factors on population fluctuation of whitefly (Bemisia tabaci) and its natural enemies in cotton agroecosystem

Aim:Whitefly a phloem-feeding insect, is economically more important because it causes reduction in yield of cotton. Various weather parameters also affect its population. Natural enemies of pests play a significant role in cotton ecosystem. Proper identification of change in the whitefly population and its natural enemies population along with change in weather conditions is most important for Integrated Pest Management.
Methodology:So, to study the population dynamics of whitefly and its natural enemies in cotton and their relation with weather parameters an experiment was conducted at the Research Farm, Cotton Section, Department of Genetics and Plant Breeding, CCSHAU, Hisar during kharif 2017 and 2018. To diminish the magnitude of data and to transform variables into principal components (PC), Principal component analysis (PCA) was done to describe the nature and amount of the interaction between diverse variables.
Results: It has been observed that the incidence of whiteflies started from 24th SMW and attained a peak during 34th SMW (Fourth week of August). Whitefly population exhibited highly significant positive correlation with morning relative humidity (r = 0.709**) while a significant negative with maximum temperature (r = -0.535*). Predators population viz.,Chrysoperla, coccinellids, and spiders population also attained their maximum population in the month of August and exhibited highly significant positive correlation (r = 0.863*, r = 0.723* and r = 0.611*), respectively with whitefly population and reported positive density-dependent response. It has been found that PC1 and PC2 confined 41.3 and 34 per cent of variability in the data, respectively.
Interpretation: The present study focused on the population fluctuation of whiteflies and its natural enemies in cotton and also their correlation with weather parameters and also the relationship between whiteflies and its natural enemies.