1a. Objectives (from AD-416):
Objective 1: Improve and develop new monitoring strategies for stored-product insects, and improve methods for interpretation of monitoring information to aid in pest management decision making. Sub-objective 1.1: Determine relationships between outside trap captures and movement into and out of storage structures. Sub-objective 1.2: Develop and improve pheromone-based monitoring programs for stored-product insects. Objective 2: Improve and develop decision-making tools for management of stored-product insect pests. Sub-objective 2.1: Develop simulation models for insect pests of stored commodities. Sub-objective 2.2: Develop models to estimate risk of grain damage based on sampling data for insects. Objective 3: Characterize the biology of and develop management strategies for new insect pests of stored products. Sub-objective 3.1: Evaluate and develop potential attractants for stored- product psocids. Sub-objective 3.2: Evaluate response of psocid pests of stored products to temperature, moisture, and dockage gradients. Sub-objective 3.3: Determine optimal conditions for rearing hide beetles. Objective 4: Improve control strategies for insect pests of conventional and organic stored commodities, including insecticides, microbial agents, natural enemies, and physical control such as aeration and heat. Sub-objective 4.1: Assess new insecticides, microbial agents and natural enemies to control insects in stored products. Sub-objective 4.2: Develop physical methods to control insect pests of stored products. Objective 5: Identify potential genomic and proteomic targets in stored-product insect pests that can be exploited for control. Sub-objective 5.1: Obtain genetic information from stored-product insects and perform insect- and tissue-specific functional genomics and proteomics profiling to identify new potential control targets. Sub-objective 5.2: Exploit the Tribolium genome sequence to identify new control strategies for coleopteran stored-product pests. Objective 6: Improve the efficacy of alternatives to methyl bromide fumigation for management of stored-product insects in mills by 1) evaluating the efficacy of fumigation and alternative treatments in commercial food facilities and by identifying potential causes of variation, 2) determining the efficacy of high temperature treatments against stored product insects and evaluating methods to enhance susceptibility to heat, and 3) identifying factors that enhance the efficacy and spatial distribution of aerosol insecticides.
1b. Approach (from AD-416):
This project is one of two projects within the ARS that focuses on stored product insect pests of raw grain, milling and processing facilities, and grain-based finished food products. The overall goal of the project is to refine and improve management of these pests and mitigate product loss through an approach that emphasizes cooperative research among several sub-disciplines of stored-product entomology. Research will focus on improving insect detection and monitoring, increasing efficiency of pest management strategies, improving our knowledge of pest biology, and using genomics to discover totally new ways to control these pests. Much of the research is applicable to organic, as well as conventional, commodities, and some of the research deals with new pests of stored products (often referred to as emerging pests). Specific knowledge gaps being addressed are a need: to determine how resident insect populations impact pest management; for better insect attractants for monitoring pest populations; for computer models to aid in decision making for pest management; to determine environmental conditions that attract insects to commodities; to assess new insecticides for insect control; to optimize grain cooling and commodity freezing for insect control; and to identify vital genes that can be targeted for insect control. This project builds upon the results from three previous projects, and the expected benefits of this new project will enhance management of stored-product insects and ensure the quality and safety of the U.S. grain supply and grain-based finished food products.
3. Progress Report:
This report documents progress for the parent Project 5430-43000-32-00D Ecology, Genomics, and Management of Stored Product Insects which started May 2011. Under Objective 1, significant progress was made in improving and developing new monitoring strategies for stored product insects and interpretation of data to help make pest management decisions. Insect activity in the headspace of grain bins was measured and related to activity in the grain as well as temperature conditions. The impact of changes to trap design and attractant on capture of red flour beetles was assessed to improve monitoring in food facilities. Under Objective 2, significant progress was made in improving and developing decision-making tools for management of stored product insect pests. Red flour beetles exploit small accumulations of flour residue in flour mills, so the establishment and persistence of beetles on landscapes with different flour spillage abundance and distribution patterns was measured and used to develop a predictive model for red flour beetle population growth. Under Objective 3, significant progress was made in characterizing the biology of and developing management strategies for new insect pests of stored products. The attraction of multiple species of psocids to a range of grain based products was evaluated to determine the optimal attractant to use in the development of a new trap for these pest species. Further studies showed that psocids in general preferred the wheat with higher moisture content. Knowledge of ideal and detrimental humidity conditions can help in making pest management decisions. Under Objective 4, significant progress was made in improving and developing new control strategies for insect pests of conventional and organic stored commodities, including insecticides, microbial agents, natural enemies, and physical control such as aeration and heat. Tests showed that a new insecticide, dinotefuran, combined with diatomaceous earth (Alpine®), effectively controlled stored product beetle pests. Other studies showed that field populations of stored product beetles may be harder to kill than laboratory populations. An economic risk analysis model was developed based on efficacy of different insecticide treatments used to control the Indianmeal moth. A method was developed for high throughput screening of potential control products for the lesser grain borer. Under Objective 5, significant progress was made in identifying potential genomic and proteomic targets in stored-product insect pests that can be exploited for control. Studies were conducted to determine how genetic adaptations in insects enable them to compensate for various toxins. Transcriptome sequencing in phosphine-resistant red flour beetles has provided insights into genes that are different or have different expression patterns that may help insects survive phosphine exposure. Sequencing the transcriptome of the tenebrionid beetle gut has helped us to understand how beetles digest food as well as how they respond to environmental stimuli.
1. Psocids attracted to common food materials. Psocids are major insect pests of stored grains in the United States over the last decade because they cause significant weight and quality loss in stored products by feeding on grains, and further pose problems with contamination. Chemical insecticides that control stored product beetles and moths often are not effective for the control of psocids, and some species are already demonstrating resistance. Attractants are used as part of pest management systems to monitor pest insects, but none have been developed for psocids. ARS entomologists in Manhattan, KS evaluated psocid responses to attractants by using choice test experiments. Psocid adults of different ages preferred brewer’s yeast, wheat germ oil and wheat germ among several potential attractants tested. Results show these inexpensive materials could be used to develop psocid traps, which would improve monitoring and detection of this insect group in stored grains and in processing and storage facilities.
2. New insecticide effective for control of stored product insects. Alpine® (dinotefuran) is a new insecticide that is being used to control urban insect pests, and is available as a pressurized spray or as a dust combined with diatomaceous earth (DE). There is no information regarding effectiveness on stored product insects. ARS scientists in Manhattan, KS, conducted tests with both products to determine effectiveness on different stored product insects. The dust formulation was much more effective than the spray on all adult insects tested, but larvae were easily killed by both products. Results show this new insecticide can potentially replace older insecticides used to control stored product insects in milling and processing facilities.
3. RNA-Seq used to increase knowledge of phosphine resistance in stored product beetles. The fumigant phosphine is used to control pest populations in stored grains. However, there are increasing reports of phosphine-resistant insect populations and thus an urgent need to detect resistance and understand the genetic and molecular basis of resistance. ARS scientists in Manhattan, KS, collaborated with scientists at the University Viçosa, Brazil, Kansas State University, and Oklahoma State University, to study phosphine-resistant populations of the red flour beetle from the USA and Brazil, using a sequencing approach that identifies differences in sequences and gene expression in the two populations. The phosphine-resistant flour beetle strain from Brazil has differences in genetic sequences and gene expression compared to a susceptible strain. These differences may help explain how this insect is resistant to phosphine and other insecticides, and results will help to understand resistance and improve management strategies.
Chen, H., Zhang, H., Zhu, K., Throne, J.E. 2013. Performance of diapausing parasitoid wasps, Habrobracon hebetor, after cold storage. Biological Control. 64(3):186-194. doi: http://dx.doi.org/10.1016/j.biocontrol.2012.11.007.