The influence of temperature (15, 20, 25, 30, 35 and 40 °C), humidity (0 and 6 h in a moist chamber), inoculum concentration of Acidovorax avenae subsp. citrulli (0; 3.4 x 10¹; 3.4 x 10²; 3.4 x 10³; 3.4 x 10(4); 3.4 x 10(5); 3.4 x 10(6) and 3.4 x 10(7) CFU.ml-1) and fruit age (40, 50, 60 and 70 days) on the severity of fruit blotch of melon (Cucumis melo) yellow type was studied. Fruits were inoculated by sub-epidermal injection and incubation period, external lesion diameter and lesion depth were determined . The incubation period was not significantly affected by temperature in fruits kept within or without a moist chamber. Larger external lesions were observed on fruits kept at 30 °C (19.5 mm) in a moist chamber for 6 h and 35 °C (15.3 mm) without a moist chamber. Deeper lesions were observed on fruits kept in a moist chamber at 30 °C (17.5 mm). Under dry conditions, deeper lesions were observed at 25 °C (11.7 mm) and 30 °C (11.3 mm). No disease symptoms were observed on fruits kept at 15 and 20 °C. The humidity did not influence the lesion diameter and depth at 35 and 25 °C, respectively. Lesion diameter and depth were positively correlated to inoculum concentration. Fruit age did not significantly influence lesion diameter, 50-day old fruits showed deeper lesions.
