• H David

      Articles written in Proceedings – Animal Sciences

    • Insect vectors of virus diseases of sugarcane

      H David K C Alexander

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      Although 120 diseases of fungal, viral, mycoplasma and bacterial origin have been reported in sugarcane, insect vector associations have been established with virus/mycoplasma diseases only. Thirteen species of aphids have been identified to be vectors of mosaic and another bug,Assamia moesta Westw. is associated as a mechanical carrier. Three species ofPerkinsiella transmit Fiji disease. The leaf hopper,Cicadulina mbila (Naude) transmits streak. The mycoplasma diseases, white leaf and grassy shoot are carried over byMatsumaratettix sp. andA. moesta, respectively. A mealy bug has been reported to be a vector of spike disease. The future lines of approach for insect vector associations are also discussed.

    • Application of sex pheromones in sugarcane pest management

      H David B F Nesbitt S Easwaramoorthy V Nandagopal

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      Seven species of moth borers are known to cause heavy losses in sugarcane production in different parts of the country. Because of their concealed habits, the control of these borers becomes complex and hence a number of methods have been tried to suppress their field population. The sex behaviour of four species of these borersviz., internode borer, stalk borer, shoot borer and top borer have been studied in recent years and among these the internode borer and stalk borer have been found to have potent sex attractants. Mass trapping may be useful in the management of internode borer while disruption technique is likely to be useful in the case of stalk borer. In both the borer species, the synthetic pheromones will be highly useful in monitoring their activity.

    • Influence of nutrition on the reproductive biology of sugarcane pests and their natural enemies

      H David S Easwaramoorthy K Subadhra

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      The survival and fecundity of the scale insect,Melanaspis glomerata (Green) varies according to the sugarcane varieties on which they feed. When the sugarcane setts infested with scale insect crawlers were maintained on different nutritional bases, high survival and fecundity were observed in distilled water as the medium. The nutrition of immature stages and adults of the egg parasite,Trichogramma spp. was found to influence the longevity and reproduction. The eggs ofCorcyra reared on groundnut kernels had appreciable quantities of growth promoting amino acids like glysine, analine and tyrosine and this influenced the size of the adult parasites. The higher fecundity of the parasites obtained from the eggs ofCorcyra reared on greengram was attributed to the maximum level of nutrients. The individuals which emerged from superparasitized eggs showed reduction in mating and fecundity because of the sharing of the nutrients. The adult longevity and fecundity increased when fed with different sugars in the presence of host eggs. Increase in the protein content in adult diet decreased the fecundity.

      In the larval parasite,Sturmiopsis inferens the qualitative variation in the nutrient contents due to interspecific variation and quantitative variation as influenced by the size of the host influenced the reproductive capacity of the parasite.

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