The infestation of Melanagromyza sojae infesting black gram started from 1 st WAS i.e., 13 th SMW (16.67%) during summer, 2017. Thereafter the infestation increased gradually and its highest infestation was observed on 7 th May 2017 i.e., 19 th SMW (78.33%). Minimum temperature (MinT) and morning vapour pressure (MoVP) showed highly significant positive association with infestation (0.509** and 0.522**, respectively). Evening vapour pressure (EvVP) exhibited significant positive association (0.440*). During summer 2021, infestation initiated from 1 st WAS i.e., 13 th SMW (15.00%) then infestation increased gradually and its peak incidence was observed on 5 th May 2021 i.e., 18 th SMW (80.00%). Minimum temperature (r = 0.769**) and evening vapour pressure (r = 0.510**) exhibited highly significant positive association, while morning vapour pressure (0.495*) showed significant positive association.

Six sowing periods during summer (4 th week of February, 1 st week of March, 2 nd week of March, 3 rd week of March, 4 th week of March and 1 st week of April) was evaluated for its impact on incidence of stem fly, Melanagromyza sojae (Zehntner) infesting black gram at Entomology Farm, B. A. College of Agriculture, Anand Agricultural University, Anand. The black gram crop sown during 1 st and 2 nd week of March exhibited low larval (0.22 and 0.26 /plant), pupal (0.22 and 0.27 /plant) counts of the pest as well as less infestation (28.38 and 29.73%, respectively) and tunnelling (8.92 and 9.45%, respectively) than rest of the sowing periods during summer season. Maximum seed yield was recorded in the crop sown during 2 nd week of March (597 kg/ha) followed by 1 st week of March (564 kg/ha).

A field experiment on the seasonal incidence of stem fly, Melanagromyza sojae (Zehntner) infesting black gram was carried out in variety GU 1 (Gujarat Urd 1) during kharif 2017 and 2021 at Entomology farm, B. A. College of Agriculture, AAU, Anand. Infestation of M. sojaewas observed from 1st WAS i.e., 34th SMW. Later on, infestation increased gradually and its highest infestation was observed during the 39th SMW i.e., 68.33 and 73.33% of kharif, 2017 and 2021, respectively. Stem fly infestation exhibited a highly significant positive association (r = 0.519** and 0.655**, respectively) with bright sunshine hours (BSS) and maximum temperature (MaxT), respectively. Abiotic factors viz., rainfall (RF) exhibited a significant negative association (-0.458*), while evaporation (EP) showed a significant positive association (0.466*).