Abstract
Cockroach control tests in apartment houses were done. In the apartment houses in Fukuoka area, only the cockroach, Periplaneta fuliginosa Serville, was found and no other species was observed. Ten or twenty times dilution of 5% emulsifiable and mixed emulsifiable concentrate 4% dieldrin with 6% lindane were sprayed at the rate of 40cc per m^2 in kitchens and lumber rooms. By a residual spraying on lower walls of the rooms, the roach was fairly controlled. By twice treatments in May and September, the roach was almost exterminated. In this case, the time of the treatments was decided in accordance with seasonal occurrence of the cockroach. On the distribution of roaches in apartment houses in this area, the following characteristics were observed. That is, on the vertical distribution, the adults and larvae were mainly found at the 4th floor (highest floor), and at the 1st floor as next. In the horizontal distribution, the roach was mainly inhabited at the central part. It was also observed that the peaks of occurrence of roaches were observed in August and September. In the restaurants, German cockroach, Blattella germanica L., was found more than any other species, and P. fuliginosa and P. americana L. were also found but very fewer than B. germanica. According to the LD-50 test by topical application method against those cockroaches both collected and bred, the following results were observed. Some colonies of B. germanica showed slightly resistance to lindane, but none of them showed the resistance to dieldrin. Against organophosphorus insecticides, the roaches were as susceptible as the normal strain. For the control of German roach in restaurants, approximately 2.5-fold dosage per unit area of the chemicals (dieldrin 4% E. C or dieldrin 4% and lindane 6% mixed E. C.) was required. This may be ascribed to the complicated structure of the restaurants. The treatment of DDVP by fog machine was ineffective, and also the residual spraying of diazinon E. C. to lower walls of rooms was not enough to control the pest. It was confirmed that effective control was given by the treatment of dieldrin which was remarkably stable and then persistent for a long time. According to the results as stated above, it is considered that the treatment of residual spraying to lower walls in the rooms using organic chlorinated insecticides, i.e. dieldrin E. C. or mixed E. C. of dieldrin and lindane, is the most effective and standard method for cockroach control in the present status.
