Efficacy of Phosphine Gas Against the Darkling Beetle (Alphitobius diaperinus)

ABSTRACT

Background: The darkling beetle, Alphitobius diaperinus is the most commonly beetle found in poultry sheds and causes economic and sanitary impact in the poultry industry. The life cycle of the mealworm can vary from one to three months depending on environmental conditions, and adults can survive for up to one year. The insect lives in the poultry litter where it eats feed and organic waste. The temperature in the poultry house and the accumulation of feed and organic matter promote ideal conditions for beetle infestation. The consumption of beetles affects feed conversion in poultry, especially in the first days of life and it is often cited as a vector of viral, bacterial and parasitic pathogens. The control of its populations is generally achieved by insecticide application on the walls and floor, but resistant populations of beetles are often reported. Phosphine gas is used as a fumigant to control insects in stored grain. In this study the efficacy of phosphine gas against this beetle was evaluated. Materials, Methods & Results: Two experiments were conducted one in vitro trial, and a trial simulating field conditions. The in vitro trial aimed to evaluate the exposure time required (ETR) to obtain 100% insect mortality, in the presence and absence of wood shavings. Adults and larvae were tested separately. In treatment T1, 100 adult beetles were placed in a petri dish without poultry litter; treatment T2, had 100 adult beetles per plate and filled with sterilized poultry litter. Treatments T3 andT4 had 100 A. diaperinus larvae per plate, in absence and presence of poultry litter, respectively. Three repetitions were performed for each treatment. Insect mortality in plates was monitored at 5 min intervals. The absence of beetle movements after shaking the plate was considered an indicator of insect mortality. The field evaluation was carried out in a poultry house with litter infested with A. diaperinus. [...]