2008 Annual Report
1a.Objectives (from AD-416)
The goal is to maximize the effect of physical, chemical, and biological stressors to control stored-product insects in raw grains and processed grain products. Stored-product insect pests reduce the quality of stored grain and grain-related products in the U.S. and in the world. We will identify new methods of controlling insect pests in stored products, targeting controls to specific sites or areas, and determining how insect immune systems can be exploited to improve efficacy of new control strategies. We will identify and refine alternative insecticides, biologically-based control methods, and physical controls to manage stored-product insect pests. We will evaluate selective targeted controls and application strategies to manage insect pests in different stored-product systems.
1b.Approach (from AD-416)
Laboratory and field experiments will identify new biologically-based methods and reduced-risk insecticides to control stored-product insect pests, evaluate synergistic and additive effects from selected control agents, and to further refine physical controls, such as heat and aeration, to modify storage environments. Laboratory and field tests will investigate targeted applications of control agents, detect pathogen virulence in field populations of stored-product insects, and examine new methods for using pathogenic controls to regulate pest populations in stored products. Our research will also include detailed analysis of the cuticular lipids in the insect cuticle, and analysis of how these properties affect their response to various control agents. We will investigate how insect immune responses are regulated and how physiological responses can be interrupted and manipulated to enhance efficacy of control agents. Our research will provide new methods to control insects in raw grains and processed grain products, strategies for integrating different control agents, information on using targeted controls for specific areas within stored-product facilities, and knowledge of how the insect immune system could be exploited to improve control from reduced-risk insecticides and insect pathogens. Results will provide practical information for minimizing risk, quality deterioration, and economic damage caused by stored-product insects.
Our research has shown the potential for the expanded use of insect growth regulators to control insect pests of bulk grains and in milling, processing, and warehouse facilities. We also identified a new neonicotenoid insecticide that will control beetle pests in flour mills. The insect growth regulators may be used in combination with other control strategies, including inert dusts, microbial pathogens, and fungal pathogens, to manage insect pest populations in stored products. We have also shown the potential for the expanded use of non-chemical controls, using aeration to cool grains during the summer and during autumn, using heat to kill insects inside of grain kernels, examining natural varietal resistance in different grain crops, and combining this resistance with reduced-risk insecticides. Studies are also underway to assess the prevalence and impact of insect pathogens in field populations of some of the major stored-product insect pests. We are also making progress in quantifying the genetic responses of insect pests to stresses imposed by insecticides, pathogens, and control agents. The research conducted in our management unit primarily addresses Component IV, Postharvest, Pest Exclusion, and Quarantine Treatment of National Program 304, Crop Protection and Quarantine. The research also supports Component II, Biology of pests and natural enemies and Component V, Pest Control Technologies of NP 304.
New aerosols control stored-product beetles. There is little published information regarding the effectiveness of insecticidal aerosols in commercial facilities, and results of laboratory trials may not always be an indication of effectiveness in field applications. Scientists at the Grain Marketing and Production Research Center conducted tests by exposing adult red flour beetles and confused flour beetles, along with pupae and larvae, to pyrethrin insecticide inside a commercial warehouse. In addition, larvae of the beetles and eggs of the Indianmeal moth were also exposed to the insect growth regulator methoprene. Although the aerosol system effectively distributed the insecticide throughout the test facility, the red flour beetle was more susceptible than the confused flour beetle to the pyrethrin insecticide. Methoprene was effective against larvae of both beetle species, but eggs of the Indianmeal moth were difficult to kill. Results show that the effectiveness of aerosols will depend on several related factors, including how well the application system distributes the insecticide, the toxicity of that insecticide, differences in susceptibility between target insect species, and variation in susceptibility of individual life stages. This research addresses National Program 304-Crop Protection and Quarantine, Component IV-Postharvest, Pest Exclusion, and Quarantine Treatment, Problem G.-Development of New and Improved Control Technologies.
Rice varieties vary in susceptibility to the lesser grain borer. The hull of rough rice may offer some protection from the lesser grain borer, a major internal pest of stored grains, because this insect lays an egg on the kernel, and the young larvae must hatch and enter the hull to feed on the kernel. Scientists at the Grain Marketing and Production Research Center exposed young larvae of the lesser grain borer on 28 different rice varieties, determined the percentage of solid versus split and cracked hulls, and thickness of the hull. More progeny were produced on rice varieties with higher percentages of cracked hulls and on those varieties with thinner versus thick hulls. Specific varieties were identified as susceptible or tolerant based on the hull characteristics. This research addresses National Program 304-Crop Protection and Quarantine, Component IV-Postharvest, Pest Exclusion, and Quarantine Treatment, Problem E.-Biology and Ecology of Stored Product Insect Pests.
Modified atmosphere increases efficacy of beneficial fungus. Atmosphere modification being a widely adopted means of insect control in stored products, a study investigated its effect on the efficacy of the insecticidal fungus, Beauveria bassiana, on one of the most difficult to control pests, the red flour beetle. Oxygen reduction but not CO2 elevation for the first 72 hours of fungus exposure resulted in significantly greater larval mortality than was observed with fungus exposure under ambient atmospheres. Both treatments reduced pupation of older larvae suggesting that slowed development may be a beneficial factor for fungal efficacy. Carbon dioxide elevation, but not oxygen reduction, significantly affected the mortality of adult beetles. Carbon dioxide elevation significantly reduced fungus germination and growth rates, but oxygen reduction affected only the growth rate. This research addresses National Program 304-Crop Protection and Quarantine, Component IV-Postharvest, Pest Exclusion, and Quarantine Treatment, Problem G.-Development of New and Improved Control Technologies.
Varietal resistance in rough rice combined with an insecticide. Different varieties of grain crops, including rough rice, vary in their susceptibility to stored-product insects. Scientists at the Grain Marketing and Production Research Center conducted a test by exposing adult lesser grain borers, a major insect pest of stored grains, on susceptible and resistant varieties of rough rice treated with increasing rates of diatomaceous earth (DE). The production of offspring from these exposed adults was assessed as a measure of control. As the rate of DE increased to the maximum rate specified on the insecticide label, few offspring were produced on 3 of 4 resistant varieties. In contrast, more offspring were produced on the 4 susceptible varieties. There was also a corresponding increase in the percentage of insect-damaged kernels in the susceptible varieties compared to the resistant varieties. Results show that combining natural varietal resistance with a reduced-risk insecticide such as DE could limit lesser grain borer populations and result in less damage to the commodity. This research addresses National Program 304-Crop Protection and Quarantine, Component IV-Postharvest, Pest Exclusion, and Quarantine Treatment, Problem G.-Development of New and Improved Control Technologies.
New insecticide to control stored-product beetles. Phantom® is a new insecticide that specifically targets insect metabolism, and is registered to control termites, cockroaches, and ants. If this chemical could be registered to control stored-product insects inside facilities where processed food is stored, it would enable the use of an insecticide that would be of limited risk to humans. Scientists at the Grain Marketing and Production Research Center conducted tests by exposing adult red flour beetles and confused flour beetles on concrete, tile, and plywood surfaces treated with Phantom®. The insecticide was more effective on concrete compared to tile and plywood, and the red flour beetle was more susceptible than the confused flour beetle. Most beetles died within 1-7 days after they were exposed on the treated surfaces. Results show that this insecticide can be incorporated into management plans for stored-product insects in food processing facilities, and the insecticide label is being amended to include control of these insects. This research addresses National Program 304-Crop Protection and Quarantine, Component IV-Postharvest, Pest Exclusion, and Quarantine Treatment, Problem G.-Development of New and Improved Control Technologies.
5.Significant Activities that Support Special Target Populations
|Number of Active CRADAs||1|
|Number of Non-Peer Reviewed Presentations and Proceedings||6|
Chanbang, Y., Arthur, F.H., Wilde, G.E., Throne, J.E. 2007. Efficacy of diatomaceous earth and methoprene, alone and in combination, against Rhyzopertha dominica (F.) (Coleoptera: Boxtrichidae) in rough rice. Journal of Stored Products Research. 43(4): 396-401. Doi: http://dx.doi.org/10.1016/j.jspr.2006.12.003.
Lord, J.C. 2007. Desiccation increases the efficacy of Beauveria bassiana for stored grain pest insects. Journal of Stored Products Research 43: 535-539.
Tilley, D.R., Langemeier, M.R., Casada, M., Arthur, F.H. 2007. Cost and risk analysis of heat and chemical treatments. Journal of Economic Entomology. Vol. 100(2):604-612.
Vardeman, E.A., Arthur, F.H., Nechols, J.R., Campbell, J.F. 2007. Efficacy of surface applications with diatomaceous earth to control Rhyzopertha dominica (F.) (Coleoptera: Boxtrichidae) in stored wheat. Journal of Stored Products Research. 43(4): 335-341. Doi: http://dx.doi.org/10.1016/j.jspr.2006.08.003.
Arthur, F.H. 2008. Efficacy of chlorfenapyr against Tribolium castaneum and Tribolium confusum (Coleoptera: Tenebrionidae) adults exposed on concrete, vinyl tile, and plywood surfaces. Journal of Stored Products Research 44:145-151.
Arthur, F.H. 2008. Aerosol distribution and efficacy in a commercial food warehouse. Insect Science. 15(2): 133-140. Doi: http://dx.doi.org/10.1111/j.1744-7917.2008.00193.x.
Arthur, F.H., Campbell, J.F. 2008. Distribution and efficacy of pyrethrin aerosol to control Tribolium confusum (Coleoptera: Tenebrionidae) in food storage facilities. Journal of Stored Products Research 44: 58-64.
Chanbang, Y., Arthur, F.H., Wilde, G.E., Throne, J.E. 2008. Hull characteristics as related to susceptibility of different varieties of rough rice to Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae). Journal of Stored Products Research. 44(3): 205-212. Doi: http://dx.doi.org/10.1016/j.jspr.2007.10.003.
Chanbang, Y., Arthur, F.H., Wilde, G.E., Throne, J.E., Subramanyam, B.H. 2008. Methodology for assessing rice varieties for resistance to the lesser grain borer, Rhyzopertha dominica. Journal of Insect Science 8.16: 1-5.
Hubert, J., Stejskal, V., Munzbergova, Z., Hajslova, J., Arthur, F.H. 2007. Toxicity and efficacy of selected pesticides and new acaricides to stored product mites (Acari: Acaridida). Experimental and Applied Acarology. 42(4): 283-290. Doi: http://dx.doi.org/10.1007/s10493-007-9093-y.