The laboratory studies were carried out for evaluating control effects of four commercial insecticidal baits such as two different hydramethylnon [2.0%(AI)] products (DBK and Combat-Gold), fipronil [0.05%(AI)] (Combat-Power) and (0.6% chlorpyrifos [0....
The laboratory studies were carried out for evaluating control effects of four commercial insecticidal baits such as two different hydramethylnon [2.0%(AI)] products (DBK and Combat-Gold), fipronil [0.05%(AI)] (Combat-Power) and (0.6% chlorpyrifos [0.6%(AI)] (Raid-Roachbait) against German cockroaches (Blattella germanica). The control rates of four kinds of toxic baits were all 100.0% mortality of German cockroaches in 5 days after treatment. The results of chlorpyrifos and .pronil brought 100.0% mortalities in 2 to 3 days after treatment, respectively. After 3 day treatment, there was no signi.cant difference of control effect among the four toxic baits. As a result of this study, .pnonil and chlorpyrifos showed faster killing action against German cockroaches than the two hydramethylnon formulation products. In the choice test, DBK (hydramethylnon) (average 17.0 ind.) significantly attracted more German cockroaches than Combat-Gold (hydramethylnon) (avg. 7.0 ind.), Combat-Power (fipronil) (avg. 5.3 ind.) and Raid-Roachbait (chlorpyrifos) (avg. 3.3 ind.). The difference in attraction effects came 10 minutes after treatment. In order to evaluate the secondary killing effect of toxic baits by coprophagy against adult Blattella germanica, the comparative test was carried out. The adult mortality rates were signi.cantly different among the four toxic baits showing 86.7% mortality for fipronil, 60.0% for hydramethylnon (DBK), 30.0% for chlorpyrifos, and below 13.3% for hydramethylnon (Combat-Gold) in 6 days. During the .rst 12 days, .pronil showed the highest mortality rate (90.0%), followed by hydramethylnon (DBK) (60.0%). The secondary killing effect of toxic baits by coprophagy appeared in all of the baits against adult Blattella germanica.