Lethal high temperatures of onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), and control of the thrips with solar radiation by covering the ground with film

The lethal high temperature of onion thrips, Thrips tabaci Lindeman was evaluated at selected temperatures and duration combinations under laboratory conditions. T. tabaci adults were killed by exposure to either 42°C for 2 h or 44–50°C for 30 min. The soil temperatures attained under transparent polyvinylchloride film were investigated in an open field at specific times in 2006 in Osaka Prefecture. Maximum temperatures of 44°C or higher were attained from early May to late October at a depth of 2 cm beneath the soil surface. The effect of solar radiation by covering the ground with transparent polyvinylchloride film during the emergence of T. tabaci was investigated in an open field after harvesting the Welsh onions in June and July 2008. The numbers of T. tabaci emergent adults were significantly lower in the solar radiation treatment plots than in the control plots. The results suggests that T. tabaci can be killed with solar radiation by covering the ground with film, and that this control method is effective during the period from early May to late October in Osaka Prefecture.