author(s)
Rumki H Ch Sangma, Geetanjali Pradhan and RK Singh

abstract
Seasonal incidence of aphid, Macrosiphum luteum was studied on orchid, Epidendrum radicans under polyhouse conditions. The lowest mean population of 6.03 aphids (mean of thirty plants) was recorded during 17^th Standard week in April and highest population was recorded in 48 Standard week with a mean population of 94.7 aphids, respectively.The minimum and maximum temperature recorded during 17 Standard week in April, 2017 ranged from 14 °C and 23.71 °C respectively, minimum and maximum relative humidity ranged from 45.14% to 65.71% and rainfall recorded 1.87 mm. The maximum temperature recorded during 48^th standard week was 18.29 ºC and a minimum of 6.71 ºC and maximum Relative Humidity of 68.21% and a minimum of 46.14 % with a precipitation of 0.10mm. The maximum temperature of the day has positive correlation (r=0.018) with the population of aphid.