Influence of abiotic factors on population dynamics of okra aphid in okra ecosystem

Abstract

The field experiment was conducted to study the influence of abiotic factors on population dynamics of okra aphid in okra ecosystem during summer 2016 and 2017 at RARS, Karjat. The results indicated that the aphids population ranged from 5.28 aphids /3 leaves in last week of May to 22.10 aphids /3 leaves in fourth week of April in year 2016 while, in year 2017 ranged from 3.62 aphids /3 leaves in last week of May to 24.22 aphids/3 leaves fourth week of April. The incidence was noticed till the end of the crop period (last week of May) in both of the year. The aphids population gradually increased and reached its peak of 26.10 aphids in fourth week of April during 2016 and 24.2 in third week of April during 2017. Thereafter gradual decrease in population was observed. In summer 2016 the data on correlation coefficient study between pest population and weather parameters indicated that RHE (-0.749), showed highly significant negative correlation, while MinT (-0.078) and RHM (-0.078) showed negative correlation with pest activity whereas, MaxT (0.619) and BSS (0.433) showed significant positive correlation, with aphid population. While, in 2017, correlation coefficient study between pest population and weather parameters indicated that BSS (-0.316) and RHE (-0.195) showed negative correlation with pest activity whereas, MaxT (0.362), RHM (0.493) showed significant positive correlation, while MaxT (0.362) and MinT (0.161) showed positive correlation with aphid population.