Effect of Staggered Sowing on the Incidence of Sorghum Grain Midge Contarinia sorghicola (Coquillett)

Abstract

Sorghum grain midge Contarinia sorghicola Coq. (Diptera: Cecidomyiidae) is the most destructive pest of grain sorghum. A field experiment was conducted to evaluate the effect of staggered sowing on the incidence in the southern Karnataka. A susceptible grain sorghum variety CSV- 23 was sown on five dates with fortnight intervals from April to June 2018. The crop sown during the second fortnight of April recorded a maximum incidence of midges (27.53 midges/ear head) on 25 MSW (Meteorological Standard Week). Delayed sowing during the second fortnight of June reduces the incidence of sorghum grain midge (2.07 to 9.50 midges/ earhead). Effect of abiotic factors on sorghum grain midge revealed a significant positive association with mean minimum temperature (r=0.36), mean morning (r= 0.39) and afternoon relative humidity(r=0.47) while mean maximum temperature (r=-0.40) and rainfall (r=-0.33) showed a negative correlation.