CONTROLLING GLASSHOUSE CLIMATE INFLUENCES THE INTERACTION BETWEEN TOMATO GLANDULAR TRICHOME, SPIDER-MITE AND PREDATORY MITE

The effectiveness of the predatory mite Phytoseiulus persimilis in controlling spider mites on tomato crops depends on the climate which affects the balance between predator and prey. The effect of controlling glasshouse climatic conditions on the development of spider mite damage on tomato foliage was, therefore, examined. Climate was controlled by using a humidifying system and whitewash spray. Damage caused by spider mites was reduced, but the prey-predator system was more sensitive to unexpected changes in climate. After the whitewash was removed by thundery showers, more damage was caused by spider mites, there was a higher density of glandular trichomes on leaflets and a higher percentage of predators was stuck to leaflet trichomes than in the glasshouse control. This was attributed to increases in temperature and light intensity.