Performing Department
Entomology
Non Technical Summary
Over the past decade, bed bug infestations have grown virtually exponentially in both North America and Europe. Although the exact reasons for this recent resurgence are unclear, the rise in bed bug infestations has been linked to increased international travel, changes in pest management practices and the wide scale spread of insecticide resistance. Current bed bug control measures rely heavily on the use of pyrethroid insecticides. However, insecticide resistance, together with concerns over extensive use of chemicals in the domestic environment, creates a need for alternative methods of bed bug control. One approach is the formulation of fungal entomopathogens as novel biopesticides. Entomopathogenic fungi lend themselves to development as biopesticides because, like many conventional chemical insecticide active ingredients, they act through contact. Fungal species such as Beauveria bassiana and Metarhizium anisopliae are capable of infecting a broad range of insect hosts and several biopesticide products have been developed for use in horticulture and agriculture, particularly as components of Integrated Pest Management (IPM). Bed bugs are cryptic creatures that hide in the safety of a harborage during the day, and venture out only in search of a blood-meal. This cryptic behavior poses a problem for insecticide treatments that require direct contact to be effective. The aim of this project is to build on the considerable progress made in our lab towards the development of novel oil formulations and barrier treatments of B. bassiana (I93-825) and Metarhizium anisopliae (ESF1) for the control of bed bugs in domestic dwellings. We have demonstrated that by spraying an oil formulation of fungal conidia of B. bassiana onto a surface such at jersey knit cotton, we can infect bed bugs through short term exposure to the pre-sprayed substrate. Exposed bed bugs die within 3-4 days following brief contact with the sprayed surface, and additionally, carry conidia back to their harborages to infect those bed bugs that would otherwise be unaffected by a spray treatment. To prepare this technology for field-testing, we will compare the virulence of two promising commercial (EPA registered) fungal entomopathogens, to bed bugs over the temperature range of 15-30oC, evaluate the relative transfer/pick-up of conidia sprayed in oil formulations to bed bugs exposed to a range of candidate textile substrates, and design prototype spore delivery technologies for future field evaluation. Through achieving these objectives, we will be contributing to the science base for management of bed bugs and provide an effective, safe, alternative to chemical pesticides. This will contribute to safeguarding human health through the reduction in the use of chemicals in the home. Furthermore, we are confident that this technology will provide superior control of bed bug via auto-dissemination of conidia to bed bugs in inaccessible areas and provide longer term protection from re-infestation via barrier treatments to prevent immigration of bed bugs from neighboring properties.
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Goals / Objectives
The aim of this project proposal builds on the considerable progress made in this lab towards the development of novel oil formulations and barrier treatments of B. bassiana (I93-825) and Metarhizium anisopliae (ESF1) for the control of bed bugs in domestic dwellings. We have demonstrated that by spraying an oil formulation of fungal conidia of B. bassiana onto a surface such at jersey knit cotton, we can infect bed bugs through short term exposure to the pre-sprayed substrate. Exposed bed bugs die within 3-4 days following brief contact with the sprayed surface, and additionally, carry conidia back to their harborages to infect those bed bugs that would otherwise be unaffected by a spray treatment. To prepare this technology for field-testing, we have three objectives, which we anticipate will be completed within 12 months. This 12-month project has three components: 1) Compare the virulence of two promising commercial (EPA registered ) fungal entomopathogens to bed bugs over the temperature range of 15-30oC. 2) Evaluate the relative transfer/pick-up of conidia sprayed in oil formulations to bed bugs exposed to a range of candidate textile substrates. 3) Design prototype spore delivery technologies for field evaluation next year in collaboration with bed bug IPM researchers in other States. Through achieving these objectives, we will be contributing to the science base for management of bed bugs and provide an effective, safe, alternative to chemical pesticides. This will contribute to safeguarding human health through the reduction in the use of chemicals in the home. Furthermore, we are confident that this technology will provide superior control of bed bug via auto-dissemination of conidia to bed bugs in inaccessible areas and provide longer term protection from re-infestation via barrier treatments to prevent immigration of bed bugs from neighboring properties.
Project Methods
Objective 1. B. bassiana I93-825 and M.anisopliae ESF1 are virulent to bed bugs when applied to jersey knit cotton at the same concentration. However, differences in mean survival time of bed bugs was noted between isolates. In order to determine which of these isolates presents the greatest potential for re-labeling and commercialization as a biopesticide for bed bugs, we will conduct a series of comparative bioassays over the typical temperature range found in houses in NE USA. Constant temperatures 15, 20, 25, and 30 deg C and one fluctuating temperature 15 - 25 deg C. Objective 2. Our current preferred textile for evaluating efficacy of fungal treatments on surfaces is Jersey knit cotton. In previous experiments we demonstrated that application of an oil formulation of conidia to jersey knit cotton and subsequent exposure of bed bugs to this surface reduced the mean survival time (MST) of bed bugs from 4 to 3 days in comparison with paper sprayed with the same formulation. In order select the best textile for implementation as a bed skirt or barrier treatment, we will screen a variety of potential textiles for optimal conidial transfer to bed bugs using our standard bioassay design. Each textile substrate will also be evaluated for compatibility with conidial viability over time (at 25 deg C) by conducting repeat bioassays using the stored substrates at 1 month intervals. Using these results, we will not only select the most suitable substrate for long-term stability of the conidia, but also determine the ideal interval for re-application. Objective 3. Effective bed bug control can only be achieved by targeting all the areas in a home where bed bugs are found. Implementation of this fungal biopesticide is intended to be part of an approved bed bug management program. In this objective we will develop a range of designs of bed skirts and pre-treated barriers suitable for use on common bed types (Eg. divans, wood frame, bunk bed, futon, metal frame etc). We will develop spray formulations suitable for use as base board/floor interface treatment and paint-on formulations for use around electrical sockets and crevices in hard furnishings. These latter formulations will be selected with compatibility with painted and wood surfaces to ensure they are both inconspicuous and cause minimal damage or staining of these surfaces. In the event that a suitable oil formulation cannot be found due to issues of staining or damage to surfaces, we will investigate the potential for using masking tape as the barrier treatment to which the formulation is then applied.