Incidence of insect pests on radish with different dates of sowing in Meghalaya

Abstract

The experiment was conducted at Entomology Research Field, Division of Crop Science, ICAR Research Complex for NEH Region, Umiam, Meghalaya. Radish (Var: Japani white long) was sown with five different sowing dates starting from 15th October with 15 days intervals up to 15th December. The experiment was laid out in randomized block design (RBD) with four replications. Weekly observations were taken from randomly selected 5 tagged plants/plot for incidence of insect pests on radish from each sowing. Results revealed that population of striped flea beetle and crucifer flea beetle increased with successive sowing dates. Minimum population of striped flea beetle and crucifer flea beetle were noticed in first sowing with 2.90±0.74 and 0.31±0.06 beetles/plant, respectively whereas maximum population was recorded in fifth sowing with 8.95±2.26 and 4.94±1.04 beetles/plant, respectively. Maximum population of leaf beetle was recorded in first sowing with 0.13±0.01 whereas no population was found in fifth sowing. Minimum population of aphid was observed in first sowing with 1.82±0.98 aphids/leaf and highest population was noticed in fourth date of sowing with 4.87±1.89 aphids/leaf. Incidence of cabbage butterfly in different sowing of radish was non-significant. Maximum population of mustard sawfly larvae was noticed in third sowing with 0.21±0.13 larvae/plant whereas no incidence was recorded on radish in fifth sowing. Highest marketable yield was recorded in first sowing with leaves (266.53 q/ha) and without leaves (188.65q/ha) followed by second sowing with leaves (264.60q/ha) and without leaves (185.21q/ha).