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United States Department of Agriculture

Agricultural Research Service

Related Topics

Research Project: ECOLOGY, SAMPLING, AND MODELING OF INSECT PESTS OF STORED GRAIN, PROCESSING FACILITIES, AND WAREHOUSES

Location: Stored Product Insect Research Unit

2011 Annual Report


1a.Objectives (from AD-416)
This project proposes to develop better tools to monitor insect populations; to improve IPM strategies for managing insects in stored grain, food processing facilities, and warehouses; to investigate the dispersal patterns that insects utilize to avoid treatments and to reinfest facilities; and to conduct investigations on emerging pests. The primary goal of the research is to reduce losses in quality to grain and grain products caused by insects. To achieve this goal, the following research objectives will be investigated:.
1)improve methods for detecting insects in raw grain and other products by determining the critical factors that affect trap catch, and the relationship between trap catch and actual level of product infestation;.
2)determine how the spatial distribution and population structure of stored-product insects inside and outside processing facilities before, during, and after control treatments affects re-infestation potential;.
3)develop models that predict insect population growth in grain processing facilities and warehouses, and use the models to investigate optimal IPM strategies; and.
4)determine the prevalence and pest potential of psocids and grain mites in stored grain, processing, and warehouse facilities, and conduct ecological studies on those emerging pests that prove to be economically important to implement monitoring and control strategies.


1b.Approach (from AD-416)
Laboratory and field experiments will be conducted to improve insect detection, sampling, and monitoring techniques in raw grain, grain processing facilities, and warehouses. We will improve interpretation of pheromone monitoring programs by determining the important factors that influence trap capture of walking beetles in grain processing facilities and warehouses, and optimize the accuracy of pheromone traps in locating red flour beetle infestation sources. We will characterize the factors responsible for pest resurgence after fumigation or other treatments; determine how spatial distributions of insect pests change before, during, and after control treatments; evaluate how long-term population dynamics of stored-product pests influences pest resurgence following treatment; and assess the potential for pests to survive in food residues and to avoid treated areas during or after control treatments. We will develop computer simulation models for insect pests of grain processing facilities and warehouses, and use these models to optimize monitoring and management strategies. Spatial simulation models will be developed for the red flour beetle, warehouse beetle, and Indianmeal moth. We will investigate the ecology and potential economic impact of emerging pest species, such as psocids and grain mites. Determine the prevalence of these pests in grain storages and mills and develop monitoring and control strategies for species that prove to be economically important.


3.Progress Report
This report documents progress for the bridging parent Project 5430-43000-031-00D Ecology, sampling, and modeling of insect pests of stored grain, processing facilities, and warehouses, which started Feb 2010 and continued research from Project 5430-43000-027-00D Ecology, sampling and modeling of insect pests of stored grain , processing facilities and warehouses. To identify the sources of stored-grain insects captured outside of grain, studies were conducted to detect insect flight activity in the headspace of grain bins. To optimize monitoring programs for red flour beetle, experiments were conducted to improve trap capture. Experiments were conducted to determine the natural blend of pheromone produced by beetles. Comparative studies showed that response was significantly greater to the natural blend than to the commercial pheromone blend. Experiments were conducted to evaluate how the environment around a trap in a flour mill affects red flour beetle capture. We conducted research on the effects of trap density on efficiency of red flour beetle capture. To understand how environmental factors influence trap catch, we conducted studies on red flour beetle flight behavior. We made progress on determining several factors that influence beetle flight initiation. To understand how the lesser grain borer is able to move into warmer regions of wheat stored in bins and how this might affect beetle overwintering mortality, studies were conducted to determine the dispersal of lesser grain borer in temperature gradients in wheat. This study provided data on temperature preference of the lesser grain borer. Knowing the distribution of insects can help grain managers make better pest management decisions. Studies were conducted on the control of psocids in flour mills with the alternative fumigant sulfuryl fluoride. We obtained good data on mortality rates for all stages of psocids. This information will be useful for millers to determine whether sulfuryl fluoride controls psocid in flour mills. The reduced number of insecticides available for controlling insects in stored grain poses a challenge for grain managers. To better understand how an integrated pest management program compares to traditional calendar-based fumigation, simulation studies were conducted with a population dynamics model. In collaboration with scientists at Oklahoma State University, we used a model of the lesser grain borer to compare the total costs of a sampling-based Insect Pest Management (IPM) program to a calendar-based fumigation for a typical country elevator. The study showed that if insect immigration rate varies among bins, then a sampling-based IPM approach was the better alternative. A sampling-based IPM program can save grain managers money and decrease environmental impact because, instead of fumigating all of the bins at a facility, they only need to fumigate infested bins. This is the final report for Project 5430-43000-031-00D, which has been replaced by new Project 5430-43000-032-00D Ecology genomics and management of stored product insects, which started May 2011. For additional information, see the new project report.


4.Accomplishments
1. Natural pheromone blend and site of production determined for red flour beetle. Pheromone lures are important tools for both monitoring and control of pest insect populations. Although commercial pheromones have long been used for monitoring of populations of flour beetles, no one has determined either the physiological site of production or the natural blend of chemicals in the attractant actually produced by the insect, and there is evidence that the commercial blend is not optimized for maximum attractive potency. ARS scientists in Manhattan, KS, demonstrated that the natural pheromone is produced in the abdominal epidermis, and is composed of a 4:4:1:1 ratio of the four components. This natural blend was significantly more attractive than the commercial product, which is a 1:1:0:0 ratio of the four forms. The new pheromone has the potential to increase detection of the red flour beetle, leading to more effective and economical pest management programs.

2. Dispersal of lesser grain borer in temperature gradients. The lesser grain borer is one of the most common and damaging insect pests of stored wheat in the US. In the autumn, the periphery of the grain in the bin cools faster than the center, and this allows grain insects to continue to reproduce in the center. Very little is known about the movement of the lesser grain borer in temperature gradients in stored grain. ARS researchers in Manhattan, KS, investigated the movement and temperature preference of the lesser grain borer in wheat using two temperature gradients. Beetles preferred moderate temperatures but avoided the highest and lowest temperature regions. Compared to other stored grain beetles, such as the rusty grain beetle, the lesser grain borer appears to move more slowly through the grain into preferred temperature regions, which could affect the beetle's ability to overwinter in bins of stored grain because they may die from cold temperatures on the periphery of the bin before they have a chance to move toward warmer grain in the center of bins. Knowing the distribution of insects can aid grain managers in trap catch interpretation and to make better management decisions.

3. Factors affecting red flour beetle flight. The red flour beetle is one of the major pests in stored grain and in grain processing facilities throughout the world. Traps are used to monitor their movement to aid in making pest management decisions, but factors that cause red flour beetle movement are not fully understood. ARS scientists in Manhattan, KS, determined that red flour beetle flight initiation did not differ with age, sex, presence or absence of food, or duration of starvation. Both mated and virgin beetles were equally likely to fly when food was present, while mated beetles were more likely to fly than virgin beetles when there was no food present. Adults were less likely to fly when individuals of the opposite sex were present. Presence of the same sex or mixed sexes and the actual numbers of individuals present did not affect flight initiation. These results will help flour millers and pest control operators to interpret trap catches from pest monitoring programs to aid in making pest management decisions.

4. Influence of trap location within flour mill on red flour beetle capture. Pheromone traps are widely used to monitor red flour beetle activity in food processing facilities, but there is considerable variation in the environment in which traps are placed that could impact trap efficiency. Understanding how environmental factors influence trap catch is important for determining the best locations to place traps within a facility and for interpretation of trap catch data. ARS scientists in Manhattan, KS, in collaboration with Kansas State University, demonstrated that patterns of beetle capture were highly variable within the mill and tended to follow patterns of shifting distribution among floors over time after fumigations, which resulted in limited influence of local factors on trap captures. Trap locations with greater beetle captures were weakly correlated with warmer temperatures, more spillage accumulation, and close proximity to processing equipment. Results indicated that certain factors could be used by pest management professionals to select trap locations, but that the long term patterns of change in distribution over time, focusing just on these trap locations could be misleading.

5. Control of psocids (booklice) in flour mills with sulfuryl fluoride. With the impending phase-out of the fumigant methyl bromide, sulfuryl fluoride is among the most promising alternative fumigant insecticides for control of insects in flour mills. It has been evaluated for control of several insect species, but there are few data available on its effectiveness for control of stored-product psocids. Psocids are pests of stored grains and grain products in most of the world, and they have natural tolerance to some of the insecticides used for control of stored-product insects. ARS scientists in Manhattan, KS, in collaboration with Kansas State University, evaluated sulfuryl fluoride for control of different life stages of several psocid species. They discovered that adults and nymphs were killed by sulfuryl fluoride applied at the label rate. Some eggs of several species of psocids survived exposure to sulfuryl fluoride applied at the label rate. This information can be used by flour millers and pest control operators to determine whether sulfuryl fluoride will provide control of psocid populations in flour mills.

6. Sampling-based IPM program for commercial grain storage. The reduced number of insecticides available for controlling insect pests of stored grain combined with demands for pest-free food poses a challenge for managers of stored grain facilities. In collaboration with scientists at Oklahoma State University, ARS researchers in Manhattan, KS, used a simulation model to compare the total costs for sampling-based Insect Pest Management (IPM) and calendar-based fumigation for a typical country elevator in the Central Plains. The simulation studies showed that if insect immigration rate varies among bins, then a sampling-based IPM approach was the better alternative. A sampling-based IPM program can save the elevators money and decrease environmental impact because, instead of fumigating all of the bins at a facility, they only need to fumigate bins that are infested.


Review Publications
Athanassiou, C.G., Arthur, F.H., Throne, J.E. 2011. Efficacy of layer treatment with methoprene for control of Rhyzopertha dominica (Coleoptera: Bostrychidae) on wheat, rice, and maize. Pest Management Science. 67(4):380-384. doi: http://dx.doi.org/10.1022/ps.2064.

Athanassiou, C.G., Arthur, F.H., Kavallieratos, N.G., Throne, J.E. 2011. Efficacy of spinosad and methoprene, applied alone or in combination, against six stored-product insect species. Journal of Pest Science. 84(1):61-67. doi: http://dx.doi.org/10.1007/s10340-010-0326-1.

Perez Mendoza, J., Campbell, J.F., Throne, J.E. 2011. Effects of rearing density, age, sex, and food deprivation on flight initiation of the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). Journal of Economic Entomology. 104(2):433-451. doi: http://dx.doi.org/10.1603/EC10430.

Adam, B.D., Siaplay, M., Flinn, P.W., Brorsen, B.W., Phillips, T.W. 2010. Factors influencing economic profitability of dampling-based integrated management of wheat in country elevators. Journal of Stored Products Research. 46(3):186-196. doi: http://dx.doi.org/10.1016/j.jspr.2010.04.004.

Athanassiou, C.G., Arthur, F.H., Throne, J.E. 2010. Efficacy of methoprene for control of five species of psocids (Psocoptera) on wheat, rice, and maize. Journal of Food Protection. 73(12):2244-2249.

Brabec, D.L., Pearson, T.C., Flinn, P.W., Katzke, D. 2010. Detection of internal insects in wheat using a conductive roller mill and estimation of insect fragments in the resulting flour. Journal of Stored Products Research. 46(3):180-185.

Grieshop, M.J., Flinn, P.W., Nechols, J.R. 2010. Effects of intra- and interpatch host density on egg parasitism by three species of Trichogramma. Journal of Insect Science. 10(99):1-14. doi: http://dx.doi.org/10.1673/031.010.9901.

Khamis, M., Subramanyam, B., Flinn, P.W., Dogan, H., Jager, A., Gwirtz, J.A. 2010. Susceptibility of various life stages of Rhyzopertha dominica (F.)(Coleoptera: Bostrichidae) to flameless catalytic infrared radiation. Journal of Economic Entomology. 103(4):1508-1516.

Semeao, A.A., Campbell, J.F., Whitworth, R.J., Sloderbeck, P.E. 2011. Response of Tribolium castaneum and T. confusum adults to vertical black shapes and its potential to improve trap capture. Journal of Stored Products Research. 47(2):88-94. http://dx.doi.org/10.1016/j.jspr.2011.01.002.

Last Modified: 8/30/2014
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