Acta Scientiae Veterinariae ISSN: 1678-0345 [email protected] Universidade Federal do Rio Grande do Sul Brasil Gazoni, Fabio Luis; Wilsmann, César Gustavo; Flores, Fernanda; Silveira, Flávio; Azambuja Bampi, Rafael; Boufleur, Roger; Lovato, Maristela Efficacy of Phosphine Gas Against the Darkling Beetle (Alphitobius diaperinus) Acta Scientiae Veterinariae, vol. 39, núm. 2, 2011, pp. 1-6 Universidade Federal do Rio Grande do Sul Porto Alegre, Brasil Available in: http://www.redalyc.org/articulo.oa?id=289022024010 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative F.L. Gazoni, C.G. Wilsmann, Fernanda Flores,,, et al... 2011. Efficacy of Phosphine Gas Against the Darkling Beetle (Alphitobius diaperinus). Acta Scientiae Veterinariae. 39(2): 965. Acta Scientiae Veterinariae, 2011. 39(2): 965. ORIGINAL ARTICLE ISSN 1679-9216 (Online) Pub. 965 Efficacy of Phosphine Gas Against the Darkling Beetle (Alphitobius diaperinus) Fabio Luis Gazoni1,,, César Gustavo Wilsmann1,,, Fernanda Flores1,,, Flávio Silveira 1,,, Rafael Azambuja Bampi1, Roger Boufleur2 & Maristela Lovato1 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 and T4 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 housNe with litter infested with A. diaperinus. The evaluation was made in areas of 1 m² where 2 gm-3 of aluminum phosphide was applied, according to manufactures recommendation. The area of product application was covered with a plastic cover to seal the litter. Under in vitro conditions the ETR for total mortality of insects in plates with presence of litter was 15 min for larvae and 20 min for adults. In plates without poultry litter the ETR for A. diaperinus mortality was 25 and 35 min, for larvae and adults, respectively. It was observed that the presence of poultry litter in the plates reduced the volume and so increased the phosphine gas concentration, causing more rapid inset death. The mortality of adults and larvae insects occurred approximately 30 s after the exposure to the product. All the insects exposed to the phosphine gas died, resistant insects were not observed. In the field test the ETR to obtain 100% of mortality was 90 min for larvae and adults. Discussion: The phosphine gas showed good potential to be used in strategic control of A. diaperinus. The product was effective in the killing adults and larvae beetles on in vitro and in field trials. However, more studies are needed to establish the issues related to safe use of PH3 in poultry facilities. Keywords: Darkling Beetle, Pesticide, Phosphine Gas, Poultry. Received: November 2010 www.ufrgs.br/actavet Accepted: February 2011 1Laboratório Central de Diagnóstico de Patologias Aviárias, Departamento de Medicina Veterinária Preventiva (DMVP), Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil. 2Centro de Diagnóstico e Pesquisa em Patologia Aviária (CDPA), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil. CORRESPONDENCE: F.L. Gazoni [[email protected] - Fone: + 55 (55) 3220- 8072]. Campus Universitário, Camobi, CEP 97105-900 Santa Maria, RS, Brazil. 1 F.L. Gazoni, C.G. Wilsmann, Fernanda Flores,,, et al... 2011. Efficacy of Phosphine Gas Against the Darkling Beetle (Alphitobius diaperinus). Acta Scientiae Veterinariae. 39(2): 965. INTRODUCTION cypermethrin use. The insects were extracted from samples of broiler-house litter by sieving through 2- Alphitobius diaperinus (Coleoptera: and-3mm screens, and then they were transported to Tenebrionidae) is an abundantly found beetle in the laboratory. They were held at 25ºC and 55% RH poultry sheds where the temperature, accumulation for at least 1wk and then tested [11]. of waste feed, organic material and adequate moisture promotes conditions for the development of darkling In vitro test beetle, making it the most abundant insect in the litter The in vitro tests were performed in sterile in poultry houses in Brazil [1]. In the first day of life Petri dishes (95x15mm) and the beetles were broilers can consume over than 450 larvae per day separated into four treatment groups in three replicates even if they have food at their disposal [2]. This as follows: Treatment 1 (T1) with 100 adult of lesser consumption affects feed conversion in poultry, mealworm per plate without litter and Treatment 2 especially in the first days of life [3] and they are (T2) containing 100 adult beetles per plate with sterile often implicated as a vector of viral, bacterial and litter. Treatments 3 (T3) and 4 (T4) were composed parasitic pathogens [4-6]. In addition, this insect can of 100 larvae per plate in the absence and presence cause significant damage to broiler houses by of litter, respectively, and a control treatment (TC) tunneling into the structural components of the sheds without exposure to PH3. The plates were exposed and into clay floors [6]. to 2 mg-3 of aluminum phosphide, according to the The control of its populations is generally manufacturer prescriptions for other insecticide uses achieved by spraying insecticide on the walls and [10]. The plates were monitored in five min intervals floor, after litter removal and before placing new in order to observe the exposure time required (ETR) chicks. Resistant populations are often reported [7- to obtaining 100% insect mortality. The beetle’s 9], and this concern has prompted a search for new mortality was assessed according to the literature [12] alternatives to minimize the resistance problem. and a correction for the control of mortality was made Phosphine gas (PH3) is extremely toxic to by the use of Abbott’s formula [13]. insects and is the most used fumigation agent in stored In situ test grain for controlling pests. Its mechanism of action is based on partial inhibition of the electron transport The tests were made at a poultry house with chain that increases the generation of superoxide 8,000 birds in Garibaldi, RS, Brazil. Three sites of 1 dismutase and hydroxyl radicals. These radicals m² for each treatment in random locations were initiate lipid peroxidation, which results in cell damage separated into the shed from a control treatment, followed by insect’s death [10]. immediately after removing the chicken flock. The This study aimed to evaluate the efficacy of litter was excavated in order to check its depth to phosphine gas againts the darkling beetle (Alphi- determine what volume of litter would be exposed to PH . Then the dose required for the volume was tobius diaperinus) in vitro and in a poultry facility. 3 calculated. Thus, the dosage of 2 mg-3 of aluminum MATERIALS AND METHODS phosphide was used. After determining the dosage, PH3 was inserted into the litter in a depth of about 15 Chemical cm, covered with plastic and sealed the edges. There The Gastoxin® is composed of aluminum were three treatments with 30, 60 and 90 min of phosphide (57% m/m), aggregates and adjuvants. It exposure to the product before the plastic was is presented in 3 g fumigation pellets. The product is removed and the insect mortality was assessed. manufactured by Bernardo Quimica SA1. Statistical analysis Insects Statistical analysis of data obtained was Beetles were collected from two Brazilian performed to test mean comparison by Tuckey, with broiler farms in the south of Brazil, a traditional a significance level of 95%. The test was performed poultry producing center, with varying histories of using the SAS statistical program 9.1 version [14]. 2 F.L. Gazoni, C.G. Wilsmann, Fernanda Flores,,, et al... 2011. Efficacy of Phosphine Gas Against the Darkling Beetle (Alphitobius diaperinus). Acta Scientiae Veterinariae. 39(2): 965. RESULTS the insects gradually until 100% of mortality. All samples tested were 100% susceptible to PH3, In vitro test showing no signs of resistance. Data of in vitro tests performed in this Field trial experiment are shown in Table 1. The data shows The field trial obtained 100% mortality of that the presence of litter reduced the ETR when insects after an exposure period of 90 min (Table compared with T1 (P <0.05) occurring 100% of 2).