Influence of different temperatures on the tachinid parastite,Sturmiopsis inferens [Dip.]

Abstract

The influence of constant temperatures of 27, 29, 31 and 33oC and alternating temperature of 31/33oC (18/6 h) on Sturrniopsis inferens TOWNSEND was studied during 12 successive generations. The larval and pupal periods for male parasites were 13.5 + 0.5 and 11.0 _+ 0.3 days respectively and for female 12.8 _+ 0.5 and 11.1 + 0.3 days respectively in the 1 st generation at 27 ~ C. It decreased progressively with increase in temperature. Survival of females, fertility and fecundity were adversely affected at higher temperatures. A temperature range of 27-29 ~ C appeared to be optimum for mass rearing of the parasite in the laboratory. The high~ premature mortality observed at a constant 33oC was not observed at temperatures fluctuating between 31/33oC, Presumably under field conditions, where temperature is constantly fluctuating, the flies will be able to withstand a comparatively higher temperature. TOWNSEND (Dip. : Tachinidae) is an important larval parasite of sugarcane shoot borers, Child infuscatellus SNELLEN (anon., 1971 ; KALRA & DUTTA, 1971) and C. auricilius DUDGEON (SINGH & YADAV, 1 979) in certain parts of India in recent years. The attempts made to breed it in the laboratory (DAVID et ai., 1980) and to colonize it in a new area (our unpubl, data) have given encouraging results. The success of a natural enemy in biological pest suppression depends mainly on its ability to survive in the environment. Environmental factors that influence the success of a natural enemy are weather, food, resource other than food (i. e. a particular place to live) and other organisms of the same and different species (SoLoMON, 1949). Among these factors, temperature plays a key role and affects the survival and activity of the parasite. In this laboratory study, an attempt was made to study the influence of temperature on S. inferens and to establish the optimum temperature for mass-rearing the parasite in the laboratory for field colonization. Sturmiopsis inferens MATERIALS AND METHODSA culture of S. inferens was started with puparia collected from cane fields around Coimbatore on larvae of the shoot borer, C. infuscatellus. One hundred freshly formed

Larvipositional behaviour ofSturmiopsis inferenstns. (Tachinidae: Diptera) on sugarcane shoot borer in India

“…The present study showed that the flies can be dissected around the seventh to tenth day to have a maximum number of active maggots needed for laboratory multiplication. This may vary with the rearing temperature, as there was a reduction in the gestation period with increase in temperature (David et al, 1981) and also according to host availability. The adults were reported to survive for 45 days under laboratory conditions and so the flies can lay almost all the maggots before they die.…”

Assessment of the tachinid Sturmiopsis inferens as a natural and applied biological control agent of sugarcane shoot borer (Chilo infuscatellus) in southern India

“…Over this period, St. inferens, just as the host, was influenced indistinctly by density-independent factors (Easwaramoorthy et al, 1991;Srikanth et al, 2001. The parasitoid's sensitivity to extremes of temperatures (David et al, 1981;Jaipal and Chaudhary, 1994) was more evident in the climatologically harsher northern India where it showed poor parasitism levels at high temperatures (Chaudhary et al, 1980); low activity in winter was associated with hibernation inside hosts (Chandra and Avasthy, 1988 b). The absence of host induced diapause in the parasitoid obviously contributed, at least partly, to the consistency of the parasitoid in the tropics, including the present study site.…”

A 100 years of biological control of sugarcane pests in India: review and perspective.

“…The influence of temperature on the tachinid St. inferens was examined [173]. The parasitoid hibernated during winter in the larvae of its host C. auricilius under north Indian conditions [174,175].…”