EFFECT OF LEAF MINER FEEDING-ACTIVITY ON THE INCIDENCE OF ALTERNARIA LEAF-BLIGHT LESIONS ON MUSKMELON LEAVES

In laboratory experiments, exposure of muskmelon (Cucumis melo) leaves to adult female leaf miners (Liriomyza trifolii) before inoculation with Alternaria cucumerina significantly increased the incidence of Alternaria leaf blight lesions. Number of lesions increased with the number of female L. trifolii present, exposure time, and increased leaf wetness hours. Linear regression analyses indicated a high degree of significance (r2 = 0.80) when the number of leaf miner punctures per leaf was regressed on the number of lesions per leaf. Regression of the number of punctures on leaf wetness hours did not provide as good a fit for the data (r2 = 0.35).