Daily Biting Research Articles

In the summers of 1962 and 1963, field experiments on the repellents to chicken-biting Culicoides species, C. arakawae and C. odibilis which are dominant components of the biting midge populations, were carried out in three poultry farms isolated from each other at the Tama-kyuryo Hill area in Yokohama City. For determination of repellency of three repellent formulations, the flock of chickens of either farm A or B was sprayed with emulsions of the repellents and successive change of the daily biting rates of midges collected by light trap at the treated pens as compared with the rates at the control farm. The spraying schedule on the two farms was changed from treated to control, alternatively. In parallel with the examination of the biting rate, the infection rate of Leucocytozoon caulleryi in a definite flock and the growth rate of both groups were also investigated. Formulation 1, containing N, N'-diethyl mtoluamide 5%, 20% pyrethrins 2.5%, piperonyl butoxide 2%, N-octyl bicylohepten dicarboximide 2%, and di-n-propyl i-cincomeronate 2% as main constituents, was more effective than formulation 2 containing the former compound and butoxy polypropylene glycol. Sprayings of 10-fold diluted emulsion of formulation 1 at the rates of 3-8ml per chick and 25ml per chicken inhibited the biting rates of Culicoides at the level of 90 to 95%. The effective duration of formulation 1 was about 1 week after a single treatment but prolonged to 2 weeks after repeated ones at 3-day intervals. In spite of rather successful protection of chickens from the feeding of biting midges, the infectivity of L. caulleryi to the birds was not lowered in 1962 where high prevalences of both biting midges and disease were shown, but other evidences indicated some possibility for protection of severe infection. The infectivity apparently decreased as a result of sprayings in the experiment of 1963 where the prevalences were comparatively low. In addition, prophylactic effect was observed on a flock treated against fowl pox infection. No adverse effects were noticed in the growth and health of chicks after repeated trials of formulation 1 at 3-day intervals over a period of 1.5 months.