エアゾール殺虫剤試験の為の新自動噴霧装置

抄録

Screening tests for various aerosol formulations of active insecticides necessitate a device which can deliver an accurate volume of aerosol insectisides at an extremely short period. For this need, an automatic mechanical device was invented. The present device is composed of a time gear which can be pre-set at any time between 0.1 sec. to 30 sec., and a magnet of which arm presses a nozzle button of an aerosol can with the constant pressure of 2kg/cm^2. A spring coil on the nozzle button, instead, pushes back the magnet-arm to cases spraying when an electric current is cut off automatically. By spraying the aerosol containing 0.3% DDVP, 0.1% pyrethrin and 1 mC of P^<32> in 90ml of xylene through 50cm long, and 9cm wide glass cylinder kept horizontally under a hood, 10 house flies were exposed at the other end of the cylinder for a test. Eight time repetitions were made for each spraying test pressed by either the device or a finger. At 10 seconds after puffing the aerosol, the air under the hood was ventilated and the number of house flies was counted. The doses of insecticide attached to house flies were calculated from the radioactivities picked up. The device was satisfactory on the following points and proved to be useful for testing aerosol formulations of active insecticides : 1) KT-50s increased proportionately with increase of the reciprocal values of time when sprayed by the device, however, irregularly by the finger. Especially, in such an extremely short spray as 0.2 sec. the finger could not control the time and tended to press longer. The standard deviations of the knock-down time were smaller when pressed by the device than by finger. This fact is of prime importance since the smaller deviations make the comparison among different candidate formulations more accurate. 2) The radioactivities, namely, the doses of insecticides picked by house flies also showed the proportional increase in accordance with increase of spraying periods when pressed by the device, but not so by finger. The standard deviations of the radioactivities of house flies were, however, indifferent between the tests by the device and by finger. There was a fine linear relationship between the log.-KT-50 and the log.-mean volume of insecticide attached to the house flies.