J. Bioi. control. 3 (1),1-3.1989 A simplified mass culturing technique for inferens Tns. H. DAVID, S. EASWARAMOOR1HY. N.K. KURUP. M. SHANMUGASUNDARAM AND G.SANTHALAKSHMI Breeding Institute, Coimbatore 641 007

ABSTRACT Attempts were made to simplify the culturing technique or tbe Tachinid parasltold, Sturmiopsis iriferens Tns. 'I'he results showed that removal of chorion ensheathing the parasltold maggots before Inoculation on host larva did not increase the per cent parasitisation significantly and tbis time consuming step In the breeding technique may be dropped. Modified Klng's technique in which maggots are suspended In 0.15% agar agar and allowed to find the host larva on their own was as effective as that or hand Inoculation of individual host larva with parasitic maggots (Scaramuzza's technique). Both these modifications In the breeding technique enabled mass production of the parasite at reasonable cost.

Key words: Sturmiopsis inj'erens, mass culturing

The Tachinid. Sturmlopsis inferens Tns., is an maintained at 27 ± 10 C and 80 ± 10 percent important larval of sugarcane shoot relative humidity as described by David et al. borer, infuscatellus Snell. (David and (1980). Mated females after completion of the Easwaramoorthy, 1986). It also parasitises the gestation period as indicated by the oozing out of stalk borer, C. auricilius Ddgn. (Singh, 1917) and a few maggots on the glass plate of the gestation Gurdaspur borer, Acigona steniellus Hampson cage were dissected in distilled water. Maggots (Chaudhary et al., 1980) in substropical to a obtained from 30 fertile females were used for the considerable extent. Studies carried out in the study. Maggots which had shed the chorion laboratory (Jai Rao and BaHgat 1968; David et al .• naturally before dissection were separated using a 1980) showed that it is an effective parasitoid of fine camlin hair brush under a binocular several species of borers infesting sugarcane. microscope. The maggots ensheathed with chorion Preliminary field testing showed that the were divided into two portions and in one chorion parasitoid can be colonised against shoot borer in was removed artificially as in Scaramuzza's areas where it occurs as a serious pest (David and technique using needles. Maggots which had shed Kurup, 1988). the chorion naturally and those in which chorion was removed artifically and, maggots ensheathed One of the pre-requisites for large scale field with chorion were inoculated separately on the colonisation is a rapid. simple and less expensive intersegmental region of healthy fourth or fifth technique of parasitoid production. Generally, the iustar larvae of shoot borer using a camlin hair parasitoid is multiplied following the technique of brush @two maggots/larva. The inoculated larvae Scaramuzza (1930) developed for breeding were reared on sug~rcane shoot bits as described Lixophaga dialraeae Tns. In this technique. mated by David et al. (1980) until pupation. Parasitioid females are dissected and the uteri are transferred puparia were collected from host larvae and pupae to 1 % saline or distilled water. The uterine and per cent parasitisationworked out for different membrane is removed and maggots are released treatments. and the ensheathing chorion is removed from the maggots artificially with fine needles under a In the second experiment. the usefulness of the binocular dissection microsope. After removing technique developed by King et ala (1979) for the chorion. two maggots are transferred onto the mass breeding L. dialraeae was compared with host body using a rme camlin hair brush. Scaramuzza~s technique with suitable Both these steps are time consuming and limit the modifications. In the modified King's technique, large scale multiplication of ~e parasitoid So. the maggots after dissection were suspended in attempts were made to simplify the technique and 0.15% agar agar solution without the removal of the results are presented in this paper. chorion. Usually 500 maggots were suspended in 5 ml of agar solution and this was uniformly spread MATERIALS AND METHODS over a Petri dish (15 x 2 cm). Fourth and fifth instar larvae numbering 250 (Host: Parasite ratio The stock '1:ulture of the parasitoid was 2 DAVID et al.

1 :2) were allowed inside the Petri dish. The Petri RESULTS AND DISCUSSION dish was covered with the cover and the whole setup was covered with a black cloth and left for There was no significant difference between 25 minutes. Then the host larvae were removed, the level of parasitism of shoot borer larvae when dried over filter paper and transferred to their inoculation was done using maggots with respective diets. C. infuscatellus larvae were ensheathing chorion or those in which chorion had reared on shoot bits as described earlier. Chilo been removed artifically (Table 1). The study partellus and Galleria mellonella (L.) larvae were clearly indicated that there is no need to remove reared on artificial diet developed by Taneja and the chorion manually, which is a laborious, skilled Leuschner, (1985) and Srivastava (1979. Personal and time consuming process. Probably host communication) respectively. For shoot borer mediated chemicals, stimulated the maggots to larvae. shoots were changed on alternate days, break open the chorion, when they were inoculated until pupation, while borer and greater with ensheathing'membrane. wax moth larvae were allowed to pupate in the diet. Parasitoid puparia were collected and percent parasitism worked out.

TABLE 1. Effect of removal or chorion on parasitization by S. inferens

Number of puparia No. of larvae Number Per cent Treatments recovered inoculated pupated parasitisation from larvae from pupae

Chorion removed 1040 48.0& artificially 169 67 29 Chorion removed b 1332 232 naturally 66 28 36.2 Chorion 1230 201 45.3& unremoved 72 3S

Numbers followed by the same letters are not statistically different (DMR1)

TABLE 2. Comparative study of the inoculation methods ofS. inferens

Method of No. of larvae Host No. of larvae No. of puparia Per cent inoculation inoculated pupated recovered parasitisation Scaramuzza's a 5404 807 500 47.97 Chilo technique infuscatellus King's a technique 5264 723 417 57.68 Scaramuzza's b 2704 974 Chilo technique 268 25.79 partellus King's 3541 technique 955 424 43.48- Scaramuzza 's 3048 1705 Galleria technique 672 39.41- mellonella King's technique 3005 2042 750 36.73-

Scaramuzza '8 4477 1189 Sesamia technique 2366 69.49' inferens King's technique 2153 600 570 52.29'

Numbers fonowed by the same letters are not statistically different (DMRT) for that host 3 Mass Culturing of S. irtferens

Significantly low level of parasitism (36.2%) REFERENCES was noticed when shoot borer larvae were Chaudhary, J.P., Yadav, S.R. and Singh, S.P. 1980. Some inoculated with maggots' that had shed chorion observations on the biology and host preference of naturally. In nature, larviposition by S. inferens Townsend (: Diptera) started on the sixth day after adult emergence and lndianf. agric. Res., 14, 147-154. continued upto twentyfrrst day (David et al., 1988) David, H. and Easwaramoorthy, S. 1986. Biological control. In indicating that the maggots were deposited as and "Sugarcane Entomology in India" (David H., Easwaramoorthy, S. and Jayanthi, R. OOs.). Sugarcane when they developed. But in laboratory, generally B reeding Institute, Coimbatore, pp. 383-421. are dissected around eighth to fourteenth day David, H. and Kurup, N.K. 1988. Tachinid parasites for only when more than 80% of the maggots have management of sugarcane borers. In "Biocolltrol completed their development. Hence those Technology for Sugarcane Pest Management". (David, H. maggots that were retained inside the uterus after and Easwaramoorthy, S. eds.) Sugarcane Breeding shedding of chorion for a considerable period for Institute, Coimbatore. p 52-66. want of host. may have lost their parasitising David, R., Easwaramoorthy, S., Nandagopal. V., Kurup, N.K., Shanmugasundaram. M. and Santhalakshmi. G. 1988. ability. Larvipositional behaviour of Sturmiopsis inferens Tns. (Tachinidae: Diptera) on sugarcane shoot borer in India. The level of parasitism obtained in King's Trop. Pest Mgml., 34, 267 -270. technique is comparable with that in the David, H.. Easwararnoorthy, S., Nandagopal. V., Shanmugasundaram, M., Santhalakshmi, G., Aruptbamani, Scaramuzza's technique (Table 2). In fact, M. and Kunjukrishnakurup, N. 1980. Laboratory studies on significantly higher level of parasitism was Slurmiopsis jnferens Tns., a parasite of sugarcane shoot noticed in King's technique in case of C. partellus. borer, snell. Etomon, 5, 191-200. The maggots when suspended in agar solution and IaiRao, K. and Daliga, H. 1968. Slurmiopsis inferensTowns., a allowed within short distances of the host insect Tachinid parasite of sugarcane and paddy stem borers. Tech. Bull. Commonw. Insl. bioI. Control,. 10,33-48. were able to find the host and parasitise them. This simplifies the breeding technique to a large extent King, E.G., Hartley, G.G., Martin, F.D., Smith, I.W., Summers, T.E. and Jackson, R.D. 1979. Production of the tachinid, and also reduces the cost of parasite production. Lixophaga diatraeae on its natural host and on an unnatural Normally~ a technician can inoculate only 400-500 host, the greater wax moth. Adv. Agrie. Technol. Sci. Edn. host larvae per day in Scaramuzza's technique, but Admn. U_S.D.A. AATS. 16pp. in King's technique, subject to the availability of Scaramuzza, L.C. 1930. Preliminary report on a study of the host and parasite any number of larvae can be biology of Lixophaga diatraeae Tns. J. eco12. Enl., 23, 999-1004. inoculated within an hour. Singh, O.P. 1977. Integrated control of sugarcane stalk borer, Ddgn. Sug. News, 9,36-43. ACKNO~DGEMENTS Taneja, S.L. and Leuschner, K. 1985. Methods of rearing The authors are thankful to Dr.KMohan infestation and evaluation of Chilo partellus resistance in Sorghum. Proe. into Sarghwn. Ent. Workshop, 15-2l July Naidu. Director, Sugarcane Breeding fustitute for 1984, Texas A & M University. College Station TX. USA, the facilities provided. Patenchetu, A.P. 502 324, India: ICRISAT.