Effect of Vapor Heat Treatment to Control <i>Thrips palmi</i> Karny on Greenhouse Melon Seedlings

Abstract

We evaluated the effectiveness of vapor heat treatment on Thrips palmi Karny, Bemisia tabaci (Gennadius ) , and colonies of powdery mildew, Sphaerotheca fuliginea(Schlechtendal )Pollacci, on greenhouse melon seedlings. Air was gradually heated to a set temperature(48 C )over 45 min while the relative humidity was maintained at 95%. The set temperature was then held for 8 min. The numbers of T. palmi adults and larvae, B. tabaci adults, and colonies of powdery mildew were lower on seedlings held at 48 C for 8 min than on untreated seedlings. The hatchability of T. palmi and the ratio of emerged adults were lower on treated than on untreated seedlings. Treatment at 48 C for 8 min did not visibly damage the seedlings. These results suggest that vapor heat treatment at 48 C for 8 min can effectively reduce the population densities of T. palmi eggs, larvae, pupae, and adults, B. tabaci adults, and powdery mildew on greenhouse melon seedlings.