Pollination, pollinators and fruit setting in mango

Survey of insect species visiting mango flowers indicated that highest number of species were from order Diptera (17), followed by Coleoptera (3), Hymenoptera (3), Heteroptera (3), Lepidoptera (3). There was no fruit set on completely bagged panicles. Bagged panicles opened in bloom for 24, 48 and 72 hours set 1.20, 1.20 and 1.60 fruits per panicle, respectively. Maximum (2.40) fruits per panicle were set when 10 syrphid fly (Melanostoma orientale We.) were released from 'Langra' to 'Dashehari' followed by 0.4 fruits/panicle set with 5 blueflies. Maximum number of flower visitors (60) per panicle per minute were present on late emerged panicles (20 March) and minimum (43,46 and 49) on very late (29 March), very early (20 February) and early (26 February) emerged panicle respectively. Per cent perfect flowers were maximum (11.8) on late panicles (20 March) and minimum (6.30) on early emerged panicles. Maximum fruit set (2.66/panicle) occurred on late panicles and lowest (1.66 and 1.33 respectively) on early and very late panicles. The number of pollinators/panicle/minute increased as the average temperature increased to 19.5 degrees C but decreased with further increase in temperature and with rains. Insecticide deltamethrin 0.0025%, although reduced the pollinators activity for 3 days, increased fruit set significantly by keeping the pest population at minimum.