Effect of foliar application of various insecticides on the infestation and population dynamics of stem fly in mung bean, Vigna radiata.
A field experiment was conducted during 1997 kharif and spring season in Pantnagar, Uttaranchal, India, on the efficacy of various insecticides against stem flies (Ophiomyia phaseoli, Ophiomyia centrocematis [O. centrosematis], and Melanagromyza sojae) at seedling stage of plant growth. Population dynamics was also studied during later growth stages. Minimum plant infestation (8.3 and 13.7%, respectively) was observed in the plots treated with monocrotophos in both summer and kharif seasons followed by acephate (11.7 and 15.7%, respectively) compared to the control (76.7 and 86.7%, respectively). Stem fly population in the field was significantly reduced after first spraying, where it varied from 0.33 adults with monocrotophos to 2.33 adults with nimbicidin compared to the control (4.33 adults) during the kharif season. After second spraying, it varied from 0.67 adults with deltamethrin to 5.67 with nimbicidin compared to the control (9 adults). During the summer season, the adult population varied from 0.00 with monocrotophos to 1.67 with acephate compared to 5.50 adults in the control after first spraying. The second insecticidal spray significantly reduced stem fly population (from 1.33 adults with monocrotophos to 4.3 adults with nimbicidin and cypermethrin).