ABSTRACT : The artificial diet currently used for rearing the teak defoliator, Hyblaea puera was improved by incorporating homoeopathic medicines for producing better quality larvae. The medicines evaluated included different formulations (globule and solution) and potencies of Baptisia, Sulphur, Tub Koch (Tuberculinum Koch), Syphilinium and Thuja. Sulphur 10M solution was found to be the most promising ingredient, which significantly increased the larval weight and fecundity. The study revealed that while some homoeopathic ingredients remained neutral with reference to their effect on certain growth parameters, some showed deleterious effect on larval survival and fecundity.

Key words: Artificial diet, insect, pest, teak defoliator, Hyblaea puera, homoeopathy

INTRODUCTION
The teak defoliator, Hyblaea puera (Lepidoptera: Hyblaeidae) is a serious pest of teak. Considering the need for healthy larvae for research, Mathew, et al (1990) developed an artificial diet for rearing this insect. Since then the diet has been successfully used for rearing H. puera in the laboratory for research purpose (Nair et al. 1998).

The quality of host larvae is important when they are used for mass multiplication of biocontrol agents like parasitoids, microbial pathogens like baculoviruses etc. In baculovirus mass production programmes, the weight of the host larvae is a critical factor as the output of polyhedral inclusion bodies depends on the larval size and weight (Entwistle and Evans, 1985). One of the problems encountered in the H. puera nucleopolyhedrovirus (HpNPV) production is the low weight of the H. puera larvae reared on the artificial diet. In view of the above, an attempt was made to improve the diet for production of high quality Hyblaea larvae by incorporating homeopathic ingredients in it.

Homoeopathic preparations have been tested to enhance fruiting in orchards and also for improving the health of livestock. Recently a combination of homoeopathic preparations under the name Agrocare has been submitted for patent for its claimed use in enhancing fruiting in orchards and protection of vegetation from pest and diseases (Abdul Lethif, personal communication). The impact of homoeopathic preparations on the growth of insects has never been studied.

MATERIALS AND METHODS
The existing artificial diet used for rearing H. puera was improved by adding selected homoeopathic medicines. The ingredients for preaparing one litre of diet included Agar- 20g; Kabuligram flour (Cicer arietinum)- 100g; Casein purified –30g; Yeast extract powder- 10g; Teak leaf powder-20g; Multivitamine and mineral mixture (Becadexamine)- 2 caps; Vitamin E (Evion)- 400mg; Ascorbic acid-3.5g; Sorbic acid –1g; Methyl-para-hydroxybezoate-1.5g; Streptomycine sulphate-0.25g; Formaldehyde 10%-2ml and distilled water-1000ml. The diet was prepared as per the method standardised by Mathew et al. (1990). The Agar powder was added to half of the distilled water, stirred well and brought to boil. All the ingredients except the vitamins were mixed in 500ml distilled water and blended well in a mixer grinder. To this agar solution cooled to 60 oC was added and blended. Vitamines and homoeopathic ingredient were then added and again blended. The homeopathic medicines tested in the study included Baptisia, Sulphur, Tub Koch (Tuberculinum Koch), Syphilinium and Thuja. Different formulations (solution and globule) and different potencies of the medicines were used for screening purposes. (Table 1).

The dosage of the medicine used was 100 µl in the case of liquid formulation or 11 mg in the case of globules per 1000ml of diet. Third instar Hyblaea larvae in the weight range 9-13mg were used for the experiments. Each larvae was provided with 5ml of the medicated diet (one drop/globule of medicine per 50 larvae) in the rearing tube and one litre of the diet was therefore sufficient for rearing 200 larvae. A control set was maintained in which larvae were fed with the control diet (not containing homoeopathic ingredients) . Altogether there were 20 treatments including placebo and ethyl alcohol (medium of the preparation) and one control. Each trial was carried out with 50 larvae with three replicates. Data on larval mortality, final larval weight, pupal weight, moth emergence and fecundity were gathered.. Larval growth index was calculated according to the formula suggested by Saxena et al.(1981).

Larval growth index = % of larvae pupated/   Larval period (days)

The data were analyzed using Duncan’s Multiple Range Test at a significance level of 0.05.

RESULTS AND DISCUSSION
The effect of various homoeopathic ingredients on the biological parameters studied are presented in Table.1. Among the 20 treatments, 16 showed adverse effect on larval survival as indicated by higher larval mortality than in the control. Under the remaining four treatments, namely, Sulphur 10M solution, 10M granule, and Tub Koch 10M solution and 10M granule larval mortality was comparable with the control.

The treatments, Tub Koch 10M solution and 10M globule and Sulphur 10M solution and 10M granule increased the larval weight significantly compared to the control However, between the treatments, the larval weight did not vary. In general, all sulphur treatrments and Tub Koch treatments (except Tub Koch CM solution) favoured larval weight increase. Sulphur 10M solution and 10M globule recorded the highest pupal weight compared to the control.

The growth index (GI) value in trials with sulphur 10M solution , sulphur 10M globule, Tub Koch 10M solution were comparable with control. The lowest GI value was recorded in trials with Thuja and Syphilinium.

The percentage of moth emergence was highest in the trials with Sulphur 10M solution (73 %) which was comparable with control (68%).

Significant increase in the fecundity was observed in the case of the trials with Sulphur 10M solution. The lowest fecundity rate was observed in treatments with Thuja 50M globule. Fecundity is positively correlated with pupal weight as reported by Courtney, (1981), Renwick and Radke (1982), and Karowe (1988) in lepidoptera. Different formulations of Baptsia and 50M solution and 50M globule of Syphilinium exhibited adverse effect on fecundity as none of the moths developed under these trials laid eggs.

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