Progress 09/15/04 to 09/14/06
Outputs
Commercial traps and product samples were used to determine insect species associated with five flour mills in Kansas and Nebraska. Red flour beetles and Indianmeal moths were the most abundant storage pests in all five mills, whereas the confused flour beetle, hairy fungus beetle, and foreign grain beetle were present in large numbers only in the four commercial mills. Across eight feed mills in Midwestern US, 27 species of beetles and three species of moths were captured in commercial traps. The red flour beetle was the most abundant insect species inside the mills; warehouse beetle was the most abundant species outside the mill and in mill load-out area; and Indianmeal moth was most abundant inside the mill and in mill receiving area. Approximately 18% of the 298 live insects tested positive for enterococcus bacteria, and species found were Enterococcus faecium, Enterococcus gallinarum, and Aerococcus viridans 3. E. faecium isolates displayed complete or
intermediate resistance most frequently, especially to neomycin, tetracycline, and erythromycin. Many E. faecium isolates exhibited intermediate resistance to vancomycin. The majority of A. viridans 3 isolates were susceptible to all antibiotics, while isolates of E. gallinarum displayed resistance to neomycin. The use of elevated temperatures or heat treatments for managing insect pests in food-processing facilities is becoming a popular alternative to methyl bromide fumigation. We found that young larvae (first instars) of the red flour beetle were relatively more tolerant to elevated temperatures than eggs, old larvae, pupae, and adults. Young larvae possessed two distinct HSPs with molecular masses of 70 and 24 kDa, both recognized by a monoclonal anti-bovine brain HSP 70 antibody. The increased thermotolerance in young larvae is due to increased expression of HSP 70 at higher temperatures. Time and temperature-dependent expression of HSP 70 showed that the increased
thermotolerance in young larvae might last as long as 8 h at 40oC or 30 minutes at 46oC. Three genes responsible for the production of HSP 70 in young larvae were identified and partially characterized. The survival of thermotolerant older larvae of confused flour beetle during structural heat treatments was predicted using a new model. The model is based on two nonlinear relationships: (1)logarithmic survival of old larvae as a function of time, and (2)logarithmic reduction in survival as a function of temperature. The model was validated with nine separate data sets collected during facility heat treatments. The absolute deviation of the model was within 2-7% with respect to the number of larvae surviving the heat treatment, and within 2-6% with respect to time for equal larval survival at heating rates 1.12 to 13.24 degrees C/h. The same approach was used to develop and validate a thermal death kinetic model for the heat tolerant first instars of the red flour beetle. The time
necessary to kill 50% of a population (LT50) at 1 mg (AI)/kg for lesser grain borer or rice weevil was similar with liquid and dry spinosad formulations on corn, wheat, and sorghum.
Impacts
Stored-product insects have not been surveyed in flour and feed mills in over 30 years in the United States. Our survey indicated red flour beetles to be a common and abundant pest in mills. Flour beetles are difficult to manage with residual sprays and fumigants, because populations of this pest rebound within a month after intervention with any pest management tactic. The presence of antibiotic enterococci in the red flour beetles suggests that this pest is also of a food safety concern, as these enterococci bacteria are able to transfer resistance genes to other enterococci or to more pathogenic strains of clinical importance. Effective management of red flour beetles is important in food and feed manufacturing facilities. First instars of the red flour beetle are the most heat tolerant of all life stages, and the reasons for this tolerance was determined to be due to HSP 70s. This is the first time that HSP 70s were reported from a stored product insect, the
expression pattern and genes responsible for the expression were characterized. During structural heat treatments, instead of adults, which are commonly used, first instars should be used to gauge heat treatment effectiveness because controlling first instars would control all other stages. The thermal death kinetic model we developed is new and is useful in describing survival of stored-product insects subjected to heat treatments.
Publications
- Mahroof, R., and Bh. Subramanyam. 2006. Susceptibility of Plodia interpunctella (Hubner) (Lepidoptera: Pyralidae) to high temperatures used during structural heat treatments. Bulletin of Entomological Research 97: 1-7.
- Huang, F., and Bh. Subramanyam. 2006. Lack of repellency of three commercial ultrasonic devices to the German cockroach (Blattodea: Blattellidae). Insect Science 13: 61-66.
- Dosland, O., Bh. Subramanyam, G. Sheppard, and R. Mahroof. 2006. Temperature modification for insect control, pp. 89-103. In, Heaps, J. (Ed.), Insect Management for Food Storage and Processing. Second Edition, American Association of Cereal Chemists, St. Paul, MN.
- Hagstrum, D. W. and Bh. Subramanyam. 2006. Fundamentals of Stored-Product Entomology. American Association of Cereal Chemists (AACC) International, St. Paul, Minnesota, 323 pages.
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Progress 01/01/05 to 12/31/05
Outputs
This report is a summary of the accomplishments for Year 5 of the Consortium for Integrated Management of Stored Product Insect Pests, which has been extended by one year. The project, a multi-institutional, multi-investigator effort included discovery research, development of potential applications, creation of content for technology transfer, and training of students, postdoctoral research associates, technicians, end users, and other clientele. The Consortium has focused on development and implementation of management programs as alternatives to OPs and the fumigants phosphine and methyl bromide. The collaboration has resulted in research-based, innovative pest management strategies that employ knowledge of ecology, sampling, modeling, geostatistics, expert systems, genetics, semiochemicals, growth regulators, reduced-risk insecticides, desiccants, extreme temperatures, and newer fumigants. A significant outcome of the research has been innovative pest management
technology being disseminated via the Internet, scientific publications, extension bulletins, and workshops. Stakeholder reviews have been solicited to evaluate project outcomes and impacts. New labels have been generated for expanded use of already registered, reduced-risk materials for new stored-product applications. We have provided cutting-edge training to students, postdoctoral research associates, extension educators, industry representatives, and pest control operators in stored-product IPM. The progress described in the report demonstrates the phenomenal success we have had in meeting a significant portion of the objectives as laid out in response to the USDA-CSREES Risk Avoidance and Mitigation Program request for proposals.
Impacts
Consumer demand for food free of pesticide residues, pesticide resistance in insects, and current regulatory climate have necessitated development effective alternatives to chemical pesticides as a means to control pests in stored products. We have developed effective management strategies for stored grain pests by using effective sampling and monitoring techniques, modeling populations, manipulating factors that create conducive environments for insect pest reproduction in storage such as temperature and moisture, and the use of natural and alternative chemical method(s) to suppress insect survival.
Publications
- No publications reported this period
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