Temperature-Dependent Development of Greenhouse Whitefly and Its Parasite Encarsia formosa

The thermal threshold for greenhouse whitefly, Trialeurodes vaporariorum (Westwood), was 8.3°C, and the developmental times, in day-degrees above 8.3°C, for the egg, 1st-, 2nd-, 3rd-, and 4th-, instar nymphs were 122.9, 63.9, 38.4, 40.1 and 115.4, respectively. The thermal threshold for the parasite, Encarsia formosa Gahan, was 12.7°C, and the developmental times, in day-degrees above 12.7°C, for the periods from oviposition to the black scale stage; from the black-scale stage to adult eclosion and from oviposition to adult eelosion were 86.9, 101.7 and 188.9, respectively. These data should enable growers to predict when to release E. formosa and when to apply pesticides with minimal effects to the parasite population.