Laboratory evaluation of toxic baits for mosquito (Aedes aegypti) larvae.

Toxic bait discs were prepared by incorporating the larvicide Abate (Temephos) technical, with yeast and dog biscuit (1:1), the latter forming the attractant source. These were assessed in 1, 10 and 25 litre aquaria and 100 litre drums against Aedes aegypti larvae. Floating as well as sinking bait discs were found equally effective in controlling free moving larvae. Larvae confined in artificially suspended cages were not affected. The baits were found effective for 5 to 6 weeks. Toxic disc bait preparation methodology and evaluation protocols are discussed in this communication.

Laboratory and field evaluation of an insecticidal trap for houseflies.

Several substances/food baits and admixtures thereof were tested in a perspex trap, treated with insecticide K-othrine@0.01 mg/cm2. Bioefficacy for housefly trapping was evaluated. Combination of ingredients was found to be more effective than individual ingredients. A combination of some easily available and cheap ingredients were employed for field trials. The admixtures of milk powder, dog biscuit, jaggery and banana peeling was found very effective. The trap efficacy including persistence of the toxicant K-othrine was observed for more than 6 months. Observations on number of flies trapped and utility of such a trap in actual field situation are discussed.

Laboratory evaluation of an ovipositional trap for mosquito adults Aedes aegypti (L.) (Diptera: Culicidae).

A trap was designed, fabricated and evaluated for trapping and killing ovipositing females of the yellow fever mosquito Aedes. aegypti. Water in which larval stages had previously dwelt for 48 hrs. formed the attractant source for ovipositing mosquito females. The trap was evaluated under different experimental conditions. Single choice and double choice experiments were performed with or without glue applied to inner surfaces, to determine trap efficacy. Effect of population size and alteration in assay conditions on percentage catch are discussed.

A device for monitoring and control of mosquitoes by behaviour manipulation.

A trap was designed and fabricated for capturing mosquito larvae based on their behavioural responses to food and light. The larvae upon entering the trap died ultimately due to asphyxiation. Maximum success was achieved with Aedes aegypti larvae in lesser water volumes. The usefulness of the device for studying the response of mosquito larvae and aquatic organisms to chemicals, baits, light, various stimuli and possible pest/vector monitoring and management in aquatic eco-system is discussed.

Comparative repellent properties of certain chemicals against mosquitoes, house flies and cockroaches using modified techniques.

Several terpenoids were assessed for their repellent/toxic properties against mosquitoes (Aedes aegypti), house flies (Musca domestica) and cockroaches (Periplaneta americana). Impregnated wide mesh netting was used in the case of the Dipterans, while treated filtered paper was employed for the bioassays with cockroaches. Persistence of the repellent chemicals was studied. Doses ranged from 5-20 gm/M2 for the Dipterans and 25-100 mg per 4 x 4 cm filter paper for the cockroaches. Dimethyl phthalate (DMP) offered the maximum protection of the chemicals tested against mosquitoes but was not so effective against house flies and cockroaches. Citral and Eugenol were effective against all the three test insects. Other test compounds afforded varying degrees of protection. Application strategy and utility of the findings are discussed.

Cyclopcidal activity of some new insect growth regulators.

A series of synthetic terpenoid diethers, with known mosquito development inhibitory activity, were tested for cyclopcidal activity against adult cyclops, Mesocyclops leuckarti. Four among these exhibited promising activity comparable to that of the conventional organophosphate, temephos, thus providing for the first time a possible reserve arsenal for the control of the guineaworm disease vector.