Wirkungen zwischen Bacillus thuringiensis Berl. und Larven der Schlupfwespe Bracon brevicornis Wesm. in bzw. an den Raupen von Sesamia cretica Led. bei verschiedenen Temperaturen

Abstract

Laboratory trials were undertaken to investigate the interactions which may occur when rearing the parasitoid,Bracon brevicornis on Sesamia cretica larvae after being injected with the pathogen,Bacillus thuringiensis under 5 constant temperatures.

Bacillus-infected larvae ofS. cretica had detrimental effects on the parasitoid's progeny e. g. prolonged periods of both cocoon stage and total development at 20 or 25 °C; and decreased number of formed cocoons or produced adults at all tested temperatures. The most deleterious temperature for the parasitoid rearing under condition of the bacterial pathogen was 30 or 35 °C.

Zusammenfassung

Laboruntersuchungen an gleichzeitig mitBacillus thuringiensis infizierten und mitBracon brevicornis-Larven besetzten Raupen vonSesamia cretica — bei 5 verschiedenen Temperaturen — ergaben, daß bei den behandelten Raupen die Entwicklungszeit des Parasitoiden bei 20° und 25 °C signifikant verringert war. In allen Temperaturstufen war die Zahl der gebildeten Kokons und geschlüpften Imagines des Parasitoiden bei den infizierten Raupen geringer, also die Sterblichkeit größer. Die für die Zucht des Parasitoiden abträglichsten Temperaturen lagen zwischen 30° und 35 °C, die zuträglichsten Temperaturen zwischen 15° und 20 °C.

With exception of females at 35 °C, no significant differences were recorded among treated and untreated vials for females or males longevity (Table 3).

In order to recognize the most detrimental temperature for the parasitoid rearing under condition of the bacterium pathogenicity, F-test was utilized to analyze the “Untreated — Treated” data. Such analysis revealed that the most detrimental temperature for such parasitoid under condition of the bacterium was 30° or 35 °C.