An Efficient Method of Mass Rearing Two Introduced Parasitoids of Noctuids (Lepidoptera: Noctuidae)

Abstract

A method is described for rearing two introduced parasitoids; Cotesia kazak (Telenga) (Hymenoptera: Braconidae) on Helicoverpa spp. (Lepidoptera: Noctuidae) and Hyposoter didymator Thunberg (Hymenoptera: Ichneumonidae) on cluster caterpillar, Spodoptera litura (F.) (Lepidoptera: Noctuidae).It facilitates the production of large numbers of parasitoids for field release.A number of species of noctuids are considered to be major pests of agriculture in Western Australia. In response to this problem several species of hymenopteran parasitoids have been introduced and reared for field release. This paper describes the methods employed in mass rearing two of the species; Cotesia kuzak (Telenga) ( = Apanteles kazak Telenga 1949), using Helicoverpa armigera (Hiibner) and H. punctigera (Wallengren) as hosts, and Hyposoter didymator Thunberg on Spodoptera litura (F.). Our procedures were adapted from those of Carl (1977Carl ( , 1978. Singh et al. (1982) and Michael et al. (1984) to allow for large-scale production. General rearing proceduresHosts and parasitoids were both reared in a quarantine insectary. The host colonies were developed from field-collected adults, while pupae imported from Switzerland (C. kuzak) and Greece (H. didymator) initiated the parasitoid colonies. Larvae of the host species were laboratory reared on an artificial diet similar to that described by Shorey and Hale (1%5), but based on soybean, bran, wheatgerm and yeast.Room temperature was 15°C. except for two periods of the day (0500-0830 and 1500-2000 h) when it was 25 "C to encourage oviposition. Natural light was supplemented by fluorescent lighting to provide 15 h light. Relative humidity was 70 & 15%. Rearing of Cotesia kazakWe presented 100 Helicoverpa larvae (late first and second instar) to five female and five male C. kazak ( > 2 d old) in 2 L plastic bottles with a mesh base (Fig. 1). The bottles were positioned on their sides with the mesh end facing the light and contained two pieces of host diet (5 mm') and two pieces of folded greaseproof paper (as larval retreats). Five thin streaks of honey were scraped onto the mesh window as food for the wasps. The insects remained in the jar for 24 h, after which the parasitoids were removed to perspex holding cages supplied with honey. Transfer of adult C. kazuk was achieved using a vacuum pump.FIG. I-Diagram of set-up used for facilitating oviposition of host larvae by C. kazak.Host larvae were allowed to develop to third instar, at which time they were moved (using a fine paintbrush) to 2 L plastic boxes with mesh inserts in their lids. Each box was supplied with two pieces of host diet and two coloured paper napkins. Parasitoid pupae were conspicuous on the coloured background and could be cut away with scissors, while those on the surfaces of the container were levered off by fingernail without mortality. Pupae were placed in paper cups inside perspex cages where they emerged 12-20 d after oviposition, or up to 180 d later under diapause-inducing conditions (< 12 h light). Unparas...

The Parasitoid Hyposoter didymator Can Transmit a Broad Host Range Baculovirus in a Two Host System

“…The additional costs associated with an extra day in the insectarium and, more importantly, with missing an extra day of H. didymator production (in the form of parasitization) do not outweigh the slight benefits of a 48 h session. These results are consistent with the majority of other studies where a parasitization time of 24 h returned more larvae parasitized than after a few hours [37,46,51]. The poorer results after a 2 h parasitization can be most likely explained because H. didymator does not have enough time to parasitize all larvae [52].…”

“…Additionally, it is more appropriate for large-scale commercial rearing. Harrington et al [51] provide a great example of the success of mass rearing in large cages, as they were able to produce an impressive 80,000 wasps in 18 months with 25% females. The lack of significant differences between collective and individual parasitization is seen in various H. didymator-rearing method investigations [37,40,41,46,52].…”

Related RNAs in Lepidopteran Cells after in Vitro Infection with Hyposoter didymator Virus Define a New Polydnavirus Gene Family

“…In the present study, we describe the isolation and characterization of three different Hyposoter didymator virus (HdV) host-expressed genes the products of which might interfere with the host physiology. This PDV is carried by the ichneumonid H. didymator, a polyphagous parasitoid able to develop in several noctuids, particularly in species of Spodoptera (Caballero et al, 1990;Harrington et al, 1993;Tillman and Powell, 1991). We show in this work that Sf9 (Spodoptera frugiperda) cell line is suitable for study of HdV expression in lepidopteran cells, since HdV expression in Sf9 cells was comparable to HdV expression in the larva's hemocytes.…”

Mass rearing of two larval parasitoids of Helicoverpa spp. (Lepidoptera: Noctuidae): Netelia producta (Brullé) and Heteropelma scaposum (Morley) (Hymenoptera: Ichneumonidae) for field release

“…Although the mass rearing of egg parasitoids, such as Trichogramma spp., is widely applied in the control lepidopteran pests, little attempt has been made to mass rear larval parasitoids in cotton (other than the small larval parasitoids, Microplitis demolitor (Murray & Rynne 1991) and Cotesia kazak (Harrington 1983;D. Murray pers.…”