Response of Aenasius bambawalei Hayat (Hymenoptera: Encyrtidae) Adults to Low Temperature Storage in Relation to Key Biological Parameters

Abstract

Studies were carried out to study the effect of storage of Aenasius bambawalei Hayat in adult stage at low temperatures viz., 5, 10, 15 and 20°C for different durations (1to 8 weeks) on the survival, longevity, fecundity and per cent females emerging in F1 progeny. One-day-old parasitoid adults were stored at each of the temperatures at 75 per cent relative humidity in full darkness. Key biological parameters of the adults surviving cold storage were studied and compared with that of unstored (control i.e. at 27°C) parasitoids. The survival of the adults was worse affected at 5°C, where the survival of the males and females was only 68 and 80 per cent, respectively, after one week of storage and complete mortality was observed after five weeks of storage. The best results were obtained at 10°C, where 100 per cent of the males and females survived storage up to three weeks and thereafter survival declined significantly being minimum of 20 and 32 per cent, respectively, after eighth week of storage. Adult longevity (19.20 and 33.00 days, respectively, for male and female), fecundity (24.00 parasitized hosts/female in five days) and per cent females in F1 progeny (48.10%) recorded after one week of storage at 10°C were comparable with the control. Thus, adults of the parasitoid, A. bambawalei could be stored only for 1 week at 10°C without any significant effect on the key biological parameters. Therefore current studies suggest that short-term storage could be used for maintaining and accumulating large number of parasitoids for inoculative releases against Phenacoccus solenopsis Tinsley.