Cool Storage of Some Parasites Used for Pest Control in Glasshouses

Abstract

SUMMARY The effect on adult emergence of storing the pupae of Encarsia formosa Gahan, Aphidius matricariae Haliday and Aphelinus fiavipes Kurdjumov at various temperatures has been investigated. Some E. formosa pupae survived storage at 10°C for periods of 41–50 days but survival was, at best, 30 per cent. Storage at lower temperatures is impracticable. After storing pupae at 13°C for 20 days before transferring them to 22°C, adult emergence was 68 per cent. Lower temperature storage of pupae of Aphidius matricariae was possible. Following the return of the pupae to 22°C after 30 days’ storage at 4 or 7°C, adult emergence was 80 and 92 per cent respectively. When the pupae were kept continuously at 4°C, 41 per cent survived and produced adults after 42–52 days. Storage of Aphelinus fiavipes pupae was tested down to 7°C. After 30 days at this temperature, adult emergence was 75 per cent when the pupae were transferred to 22°C. However, only 4 per cent survived storage when the pupae were transferred to 22°C after 83 days. Humidity did not affect the survival or emergence of the parasites. Prehminary tests with E. formosa and Aphidius matricariae showed no adverse effects on fecundity.