Influence of Four Plant Growth Regulators on Development of the Melon Fruit Fly, Bactrocera cucurbitae (Coquillett)

Experiments were conducted to assess the effect of four plant growth regulators (PGRs), namely coumarin, kinetin, gibberellic acid (GA3) and indole-3-acetic acid (IAA), on the development of the melon fruit fly, Bactrocera Cucurbitae (Coquillett) (Diptera: Tephritidae). All four compounds exerted growth- and development-inhibitory effects on the fly. Coumarin was most potent, followed by kinetin, GA3 and IAA. The first and second instars of the fly were more sensitive than the third instar. Treatment with the PGRs also prolonged the fly’s developmental period, reduced percentage emergence and increased percentage of abnormal flies emerging. At the higher concentrations tested (125, 625 and 3125 μg/ml) coumarin, kinetin and GA3 caused 100% mortality in first instars.