Abstract
The whitefly Bemisia tabaci population was controlled in a tomato greenhouse with a negative-pressure forced ventilation (NFV) system by using the parasitoid Eretmocerus eremicus from August to November. The NFV system was used in combination with a fine mesh-sized insect-proof screen, and a wind speed velocity of approximately 1 m/s was used. Similar experiments were performed in a greenhouse with natural ventilation (NV). In September, the mean temperature in the NFV greenhouse was 0.9-1.6°C lower than that in the NV greenhouse. By early- and mid-November, the number of parasitoids and the rate of parasitism in the NFV greenhouse were comparable to that in the NV greenhouse. By mid- and late-October, the number of B. tabaci adults and nymphs in the NFV greenhouse were comparable to that in the NV greenhouse. These findings suggest that the searching behavior and the development of parasitoids were not affected by the ventilation and that E. eremicus can successfully control whiteflies in an NFV greenhouse.
