Date of Graduation

5-2011

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Entomology (PhD)

Degree Level

Graduate

Department

Entomology

Advisor

Donn T. Johnson

Committee Member

Allen L. Szalanski

Second Committee Member

Randall G. Luttrell

Third Committee Member

Tanja McKay

Fourth Committee Member

Susan E. Watkins

Keywords

Biological sciences, Alphitobius diaperinus, Coleoptera, Insecticide, Lesser mealworm, Pheromone, Poultry

Abstract

The lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae), is a serious, cosmopolitan pest present in poultry production facilities, where it slows down weight gain in chicks, carries disease–causing organisms, and causes damage to poultry insulation. The first study estimated that the lesser mealworm densities in poultry litter applied to pastures were 3.5, 2.2 and 0.4 million larvae, adults and pupae, respectively, per hectare in Savoy, Arkansas. The repercussions of these adult beetles are that they often disperse to and reinfest poultry houses with the potential to vector disease to poultry, and disperse to invade human dwellings resulting in litigation. The second experiment noted an initial increase in beetle trap catches after heat was turned on in the poultry house in preparation for placement of chicks. There was a reduction in sampled densities of beetles shortly after chick placement. These observations will help decision making regarding lesser mealworm sampling and timing pesticide use.

The third experiment consisted of two behavioral bioassays. In field experiments, significantly higher numbers of beetles were found in pitfall traps treated with the lesser mealworm aggregation pheromone lure as compared to untreated checks. The laboratory two–choice pitfall trap bioassay found a combination of the aggregation pheromone and chicken droppings (CD) to be attractive to lesser mealworm larvae and adults than either odor source alone. Results indicate the potential for combining the synthetic pheromone lure with the potential attractive CD compounds to enhance trap efficacy.

The fourth objective determined respective percent mortalities and baseline dose-responses of beetles to three different classes of insect growth regulators (IGRs) including fenoxycarb, diflubenzuron, and 20–hydroxyecdysone, through topical, residual contact and feeding bioassays. In feeding bioassays, fenoxycarb and diflubenzuron were more toxic to 1st instars than 7th instars or adults, whereas ecdysone was equally more toxic to 1st instars and 7th instars than to adults. The feeding bioassay was more suitable for the 1st and 7th instar stages than adults. The residual contact bioassay exhibited slightly less percent mortality of 7th instars and adults but this bioassay most closely simulated field application of insecticides. All three bioassay methods produced usable dose-response curves for 7th instar and adults and may be used for surveying temporal changes in the IGR susceptibility to lesser mealworm.

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