Studies on the fluctuations in apple mite population and its association with weather factors in hills of Uttarakhand

Apple (Malus domestica) cultivation suffers quality loss due to attack of minute pests like Panonychus ulmi (European red mite). An exploration aimed to study the apple mite population was carried out for three consecutive years showed that the pest appeared in 13^th MSW while the peak population was recorded in the 29^th MSW and pest incidence lasted till 44^th MSW. Correlation studies done in the present investigation provided a positive correlation of three years average pest population with three years average extreme temperatures viz. maximum [r = +0.302, +0.208 and +0.076] and minimum [r = +0.571*, +0.617* and +0.490], rainfall [r = +0.529*, +0.407 and +0.405], maximum relative humidity [r = +0.555*, +0.466 and +0.417], and minimum relative humidity [r = +0.440, +0.538* and +0.390], while a negative relation of mite population with sunshine hours [r = -0.561*, -0.511* and -0.353] was noticed. Multiple linear regression equation calculated for prediction of pest population at a particular time against various weather factors resulted in 50.11% of accuracy.