Use of Formaldehyde Incorporated with Propionic Acid to Control Lesser Mealworm, <I>Alphitobius diaperinus</I> (Panzer) (Coleoptera: Tenebrionidae)

Abstract

Lesser mealworm, Alphitobius diaperinus (Panzer) is an important insect pest of poultry farms which is able to transmit several microorganisms and affect human health. The preliminary study of the life cycle of lesser mealworm on chicken feed was performed under the laboratory conditions at 25.79 ± 3.43°C and relative humidity of 78.87 ± 2.88%. The result found that the average development period of egg stage was 5.19±0.39 days, larval stage was 40-108 days with 8-11 instars, the pupal stage was 6.16 ± 0.81 days and total life cycle from egg to adult stage was 68.45 ± 15.17 days. Formaldehyde and propionic acid are additives that commonly used to control bacteria (e.g. Salmonella) and molds in animal feed. Therefore, the effect of formaldehyde incorporated with propionic acid in the control of the eggs and 1^st instar larva of lesser mealworm was investigated. The result showed that the mixture of formaldehyde and propionic acid at ratio of 0.051:0.012, 0.068:0.016 and 0.085:0.020%a.i. affected eggs and 1^st instar larva of lesser mealworm and the mortality of those stages was first found on the 7^th days after contacting chemical. The 100% mortality of eggs and 1^st instar larva was found from all ratio of those mixture at the 32^th and 14^th days after contacting chemicals, respectively.