Influence of Abiotic Factors on Pest Dynamics in Rapeseed Mustard

The study identified four key insect pests in mustard crop, i.e., mustard sawfly, mustard aphid, cabbage butterfly and painted bug. These pests have been shown to cause significant crop loss at different growth phases. During the crop's vegetative stage, the highest prevalence of mustard sawfly was observed at the 47th SMW (2.10 grubs plant-1). There was positive relationship with maximum temperature (r=0.460*) and negative correlation with maximum RH (r=0.568*). The peak aphid population occurred during the 5th SMW (126.90 aphids per 10 cm central twig plant) at siliqua formation stage. Notably, aphids exhibited a positive association with Coccinella spp. and syrphid flies (r=0.780** and r=0.805**, respectively). The cabbage butterfly's maximal density was detected during the sixth SMW (2.40 larvae plant-1). It demonstrated a substantial negative association with maximum temperature (r=-0.632*) and a positive correlation with both minimum and maximum RH (r=0.721** and r=0.455*, respectively). The maximum occurrence of the painted bug was observed during the eighth SMW (3.00 bugs plant-1), but no significant link with meteorological factors was found.