Some Demographic Parameters of Lysiphlebus confusus, L. fabarum, and L. testaceipes (Hymenoptera: Braconidae: Aphidiinae).

Lysiphlebus confusus Tremblay and Eady, L. fabarum (Marshall), and L. testaceipes (Cresson) (Hymenoptera: Braconidae: Aphidiinae) are important biological control agents for aphids. To select the appropriate biological control agent for a target pest, an understanding of the demographic parameters is essential. Therefore, a study was conducted to determine the effect of five temperatures, 12, 17, 22, 27, and 32°C, at 60% RH and 5.0 Lux photoperiod of 16:8 (L:D) h, on the parasitism rate, development, and fecundity of these three parasitoids of Aphis gossypii Glover (Hemiptera: Aphididae). Only L. fabarum parasitized at 12°C and the rate was low. None of the parasitoids was able to develop at 32°C. Lysiphlebus testaceipes had the shortest developmental period at the other temperatures. Lysiphlebus confusus and L. fabarum had similar developmental times at 22 and 27°C, with L. confusus completing its development faster at 17°C. The mortality rate of the three parasitoids varied between 3 and 20% at 17, 22, and 27°C, except for L. testaceipes which had about 53% mortality at 27°C. Lysiphlebus testaceipes had the highest net reproductive rate at all temperatures for the 2.5 and 97.5% bootstrap CIs. Lysiphlebus fabarum had the highest intrinsic rate of increase at 22°C and L. testaceipes had the highest at the other temperatures. The best temperatures for fecundity were 17 and 22°C for L. testaceipes and 22°C for the other species. Lysiphlebus testaceipes appeared to be the most suited biological control agent for A. gossypii in southern Turkey, but its intolerance to high temperature could prove problematic for its establishment and persistence in this region.