A comparative study of the efficacy of cockroach gel bait insecticides used in Thailand
Cockroach is an insect in the order Blattodea which around 30species are associated with human habitats and well-known as insect pests including American and German cockroaches. Themain objective of this study is to examine the efficiency of some gel baits insecticidal products in the Thai markets that can affect mortality rates and attraction rates of two species of cockroaches: American cockroach (Periplaneta americana) and German cockroach (Blattella germanica) under laboratory conditions. The bio-efficiency of two selected gel baits insecticidal products used for cockroach control was conducted against and compared between adult males and females of the American cockroach (Periplaneta americana) and the German cockroaches (Blattella germanica) to determine the mortality rates at 0, 5, 15, 30 min., and 1, 3, 6 12, 24 and 48 hours, respectively, then the effectiveness of each type of gel baits had been compared each other. Test substances were Acephate 3% w/w and Dichlorvos 1% w/w by testing at dosages of 0.1 and 0.25, g a.i./m2. Treatment rates were determined according to World Health Organization (WHO) testing recommendations or product label instructions. These products were tested separately against P. americana and B. germanica using surface contact exposure method. From the analysis, Acephate 3% w/w had the mortality rate at 95% whereas Dichlorvos 1% w/w had the mortality rate at 75%bothin American cockroaches and German cockroaches. Toxicity comparison of the two insecticidal products examined against P. americana and B. germanica decreased in the order of Acephate and Dichlorvos. In the attraction experiment, Imidacloprid 2.5% w/w had the attraction rates at 5.1±0.05individuals per day whereas Nano boric acid had the attraction rates at 3.07±0.12individuals per day which was the lowest level of attraction.