Temperature-Dependent Demographic Parameters of Diaeretiella rapae (M Intosh, 1855) (Hymenoptera: Braconidae) on Schizaphis graminum (Rondani, 1852) (Hemiptera: Aphididae)

Abstract

Diaeretiella rapae (M’Intosh) (Hymenoptera: Braconidae) is one of the most important biological control agents of aphids on crucifer and cereal plants. The reproduction and demographic parameters of D. rapae were investigated at six constant temperatures (10, 15, 20, 25, 27.5, and 30 °C) on the greenbug, Schizaphis graminum (Rondani) (Hemiptera: Aphididae) reared on wheat (var. Pishtaz). No development was observed at 30 °C. The highest value of mummified aphids per parasitoid female was obtained at temperature of 20 °C (120.08). However, the highest (0.374 day-1) and lowest (0.019 day-1) values of the intrinsic rate of increase (r) were observed at 25 and 27.5 °C, respectively. The shortest times for doubling and mean generation of parasitoid were resulted at 25 °C (1.85 and 7.73 days, respectively). Based on the results, a range of 20 to 25 °C is the most suitable temperature regime for D. rapae population growth on S. graminum. These findings have potential implications for integrated S. graminum management in wheat fields. However, semi-field and field studies are needed to obtain more environmentally relevant results.