Journal of Bio-Environment Control 생물환경조절학회지 ISSN:1229-4675(Print) 2765-3641(Online)

This study was conducted to investigate the effect of ventilation at high temperature on the control of powdery mildew, silverleaf whitefly two-spotted spider mite occurred at Korean melon cultivation greenhouse, and on leaf rolling and flowering of the plant in summer season. ‘Alchanggul’ grafted onto ‘Hidden Power’ rootstock was planted on soil bed with the distance of 40 cm. Three ventilation temperatures of 45°C, 40°C, and 35°C as set points were compared. Ventilation treatment was done by control of side window operation from 18th June to 13th July when silverleaf whitefly, mite, and powdery mildew were occurred in all greenhouses. The temperature inside greenhouse was increased up to the set temperature point on sunny days and maintained for about 9 hours with high relative humidity at 45°C condition. The differences of day maximum air temperature and day minimum RH were the highest at 45°C treatment. After 11 days of treatments, the damage by powdery mildew and two-spotted spider mite was almost recovered at 45°C treatment but not at 40 and 35°C. The population of silverleaf whitefly and two-spotted spider mite were significantly decreased at 45°C treatment at 14 days after treatment, while powdery mildew symptom was not significantly decreased. Leaf rolling was observed at high temperature but not severe at 45°C treatment. After 26 days of treatments, female flowers did not bloom at all at 45°C treatment, and the number of male flowers was 1.2 among 15 nodes of newly grown shoots. As the result, it indicates that ventilation at the high temperature of 45°C for about 2 to 3 weeks can be an applicable method to control above mentioned pests and disease, and to recover the vegetative growth of Korean melon by reducing flowering of the plant.