Dr. James Throne Research Entomologist (Research Leader) Stored Product Insect Research Unit Center for Grain & Animal Health Research 1515 College Ave. Manhattan, KS 66502 Voice: (785) 776-2796 Fax: (785) 537-5584 james.throne@ars.usda.gov www.ars.usda.gov/npa/cgahr/spiru/throne

James E. Throne is a research entomologist with the USDA-ARS at the Center for Grain and Animal Health Research in Manhattan, Kansas. He received his Ph.D. in Entomology from Cornell University in 1983; was a postdoctoral research associate at North Carolina State University from 1983 to 1985; and was at the USDA-ARS Stored-Product Insects Research and Development Laboratory in Savannah, Georgia, from 1985 to 1994. He specializes in the bionomics and management of stored-product insect pests, with emphasis on insect ecology and development of computer simulation models.

Biology and Control of Psocid Pests of Stored Products
Psocids, or booklice, are emerging pests of stored products, but we know little about them. We are investigating their biology and control to acquire information to help stored-product industries, such as flour mills and warehouses, make decisions about psocid management. These are very small insects, usually less than 1 mm (0.04 inches) in length, which makes them difficult to identify to species. We first determined which species were present in Kansas, and found that the psocid Liposcelis entomophila was the most common species in wheat stored in steel bins and in mills and warehouses, but an additional six species were found: Liposcelis bostrychophila, L. decolor, L. paeta, L. brunnea, L. corrodens, and Lepinotus reticulatus. Psocids usually don't have common names; instead, they are normally referred to by their scientific names. We found that using small pieces of cardboard (4 X 7 inches) is a good way to collect psocids in grain or mills. We showed that Lepinotus reticulatus developed fastest at 30-32°C (86-90°F) and 75% relative humidity, which is common for many psocids, but Liposcelis brunnea develops faster at a lower relative humidity. Most people had assumed that psocids only develop at high humidity or in wet grain. Often, it was also assumed that they can't feed on whole grain, but, we found that they can feed on and damage whole grain. The preferred grain varies with species; for example, wheat and barley were the most suitable of six grains for Liposcelis entomophila population growth, while oats were most suitable for Lepinotus reticulatus. Corn is generally a poor crop for supporting growth of psocids. Heat is being used more often to disinfest flour mills, and we showed that Liposcelis entomophila and Lepinotus reticulatus are susceptible to heat. We tested all insecticides registered for stored wheat, rice, and corn in the U.S. for effectiveness against psocids, and found that the organophosphate class of insecticides was most effective for psocid control. Effectiveness of methoprene, spinosad, and pyrethrin varied with the grain on which they were tested and with psocid species and stage (egg, nymph, or adult). We showed that the fumigant sulfuryl fluoride will kill psocids, and that eggs are the most tolerant stage. Currently, we are testing attractants for psocids, and looking at their movement in grain in response to temperature and moisture gradients. (Cooperators: Drs. Frank Arthur, Christos Athanassiou, Jim Campbell, Paul Flinn, Nickolas Kavallieratos, George Opit)

Effects of rearing density, age, sex and food deprivation on flight initiation of the red flour beetle (Coleoptera: Tenebrionidae)

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 we don’t fully understand the factors that cause their movement. We found that the rates at which red flour beetles initiate flight did not differ with age or sex, presence or absence of food, or duration of starvation. 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 tendency to fly. Older beetles (7- to 20-d old) initiated flight more quickly than younger beetles (1- to 4-d old). No young beetles flew during the first 24 hours of flight tests. Time to flight did not differ with rearing density, sex, presence or absence of food, or duration of starvation. These results will help to develop better methods for interpreting trap catches from pest monitoring programs.
     

Efficacy of pyriproxyfen for control of stored-product psocids (Psocoptera) on concrete surfaces

Psocids (insects which are also called booklice) 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. Thus, there is a need to develop alternative treatments for their control. We evaluated the insecticide pyriproxyfen, which is a newly registered insect growth regulator with low mammalian toxicity, for control of three stored-product psocid pests on concrete surfaces, which are typical of flooring in flour mills and warehouses. Exposure to pyriproxyfen reduced the numbers of all three species of psocids. The presence of food, either treated or not with pyriproxyfen, generally did not affect effectiveness of the insecticide. However, numbers of progeny generally were lower when psocids were placed on the concrete surface before it was treated with pyriproxyfen compared to being placed on the concrete surface after treatment. Few adults of any species were found in the pyriproxyfen treatments. The results indicate that pyriproxyfen is effective for control of the psocids Liposcelis bostrychophila, L. decolor, and L. paeta on concrete, although complete control was rarely achieved, and this warrants further long-term study to determine if pyriproxyfen can completely eliminate psocid populations over time.
     

Effectiveness of sulfuryl fluoride for control of different life stages of stored-product psocids (Psocoptera)

With the impending phase-out of methyl bromide, sulfuryl fluoride is among the most promising alternative fumigant insecticides. It has been evaluated for control of several insect species, but there are few data available on its efficacy for control of stored-product psocids (Psocoptera). Psocids (insects which are also called booklice) 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. We evaluated sulfuryl fluoride for control of different life stages of the psocids Liposcelis paeta, L. entomophila, L. bostrychophila, L. decolor, and Lepinotus reticulatus (psocids generally are known only by their scientific names). Adults and nymphs were very susceptible to sulfuryl fluoride. Complete adult and nymphal mortality was recorded at concentrations between 4 and 8 g/m³, except for L. decolor where all adults were killed at 24 g/m³. Eggs were tolerant to sulfuryl fluoride. Complete egg mortality was achieved at 24 and 72 g/m³ for L. reticulatus and L. decolor, respectively. Survival of L. paeta eggs was recorded even after exposure to 96 g/m³. Given that the highest label concentration for sulfuryl fluoride for a 48-h exposure interval is 31.25 g/m³, our study indicates that high doses and/or longer exposures are needed for complete mortality of eggs of L. decolor and L. paeta.
     

Lesser grain borers, Rhyzopertha dominica, select rough rice kernels with cracked hulls for reproduction

Lesser grain borers are serious pests of stored rice throughout the world. Varieties of rice vary in their resistance to insects, and resistance may be related to cracks in the hull of the rice kernel. Lesser grain borers lay their eggs loose in the mass of rice kernels, and young larvae search out and bore into a rice kernel, where they complete development. Thus, kernels with cracked hulls may be selected by females for egg laying or they may be selected by larvae because they may be easier to enter. We showed that more progeny emerged from kernels with cracked hulls when these kernels were mixed in with intact rice kernels, but some progeny did emerge from intact kernels. Thus, using grain handling methods that reduce cracked hulls in rice would be expected to reduce insect damage to rice in storage.
     

Influence of age, mating status, sex, quantity of food, and long-term food deprivation on red flour beetle (Coleoptera: Tenebrionidae) flight initiation

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 we don’t fully understand the factors that cause their movement. We found that older beetles were less likely to fly whether or not food was present, but more beetles flew when there was no food present than when provided with food. 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. More beetles flew when little or no food was present, but fewer beetles flew the longer they were starved. Our results suggest that T. castaneum uses flight as a mechanism to disperse to new environments during almost any part of their life span, unlike some other stored-product beetles that fly mostly when they are young. These results will help to develop better methods for interpreting trap catches from pest monitoring programs.
     

Stored-product Psocid Identification Website

Welcome to the stored-product psocid identification website. Over the last decade, psocids have emerged worldwide as serious stored-product pests. Most psocid pests of stored products are in the genus Liposcelis (Liposcelididae). It is common knowledge that effective pest management begins with proper pest identification. In the case of psocids, which are tiny and infestations usually comprise multiple species, identification is not straightforward. Therefore, the goal of this website is to facilitate identification of stored-product psocids and to provide information on psocid biology and control.
     Web Page

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Near-Infrared Means “Lights Out” for Stored-Grain Insects

Probit analysis programs We have developed programs for statistical analysis of data from bioassay studies. There is a program for analysis of serial time-mortality data. There are also accessory programs for transforming probit-transformed data back to proportion of test organisms responding to a stimulus, thus enabling graphing of observed and predicted data to assess goodness-of-fit of the probit line; a program for calculating relative potency of two lethal doses; and a program for determining whether slopes and intercepts from two probit equations are different. Note: The probit programs were updated in February 2006 to simplify comparisons of slopes and intercepts and calculating relative potency by including slopes, intercepts, and their standard errors and covariances in the output file for cutting and pasting into other programs. WordPerfect files describing the numerical methods used were converted to pdf files. Also, the programs were updated in October 2007 to address changes in Mathematica version 6.0. When using older versions of the programs in Mathematica 6.0, the graphs do not print correctly and several error messages are generated, but numerical output is correct. Two versions of the programs are now available - for Mathematica version 6.0 and higher, and for previous Mathematica versions. Download time-mortality and accessory programs here You may also download the program PriProbit that was developed by Dr. Masayuki Sakuma at Kyoto University in Japan. This program is for probit analysis of preference data, such as might be obtained in behavioral studies, but can also be used for analysis of dose-mortality data from bioassay studies. This program is supported by Dr. Sakuma, not USDA. USDA provides the program at this site only for the convenience of our customers. USDA does not guarantee the suitability of the program for data analysis. Questions about PriProbit and requests for support for PriProbit should be addressed to Dr. Sakuma at sakuma@kais.kyoto-u.ac.jp. The method upon which the program is based is described in:  Sakuma, M. 1998. Probit analysis of preference data. Appl. Entomol. Zool. 33: 339-347. Download PriProbit program here. Not sure which program you need? Click here. Papers describing the techniques used:   PDF  Throne, J. E., Weaver, D. K., Chew, V., and Baker, J. E. 1995. Probit analysis of correlated data: Multiple observations over time at one concentration. J. Econ. Entomol. 88: 1510-1512.   PDF  Throne, J. E., Weaver, D. K., and Baker, J. E. 1995. Probit analysis: Assessing goodness-of-fit based on backtransformation and residuals. J. Econ. Entomol. 88: 1513-1516.

PDF	Athanassiou, C.G., T.W. Phillips, M.J. Aikins, M.M. Hasan, and J.E. Throne. 2012. Effectiveness of sulfuryl fluoride for control of different life stages of stored-product psocids (Psocoptera). Pest Manag. Sci. 105: 282-287.
PDF	Fontenot, E.A., F.H. Arthur, J.R. Nechols, and J.E Throne. 2012. Using a population growth model to simulate response of Plodia interpunctella Hübner to temperature and diet. J. Pest Sci. 85: 163-167.
PDF	Kavallieratos, N.G., C.G. Athanassiou, F.H. Arthur, and J.E. Throne. 2012. Lesser grain borers, Rhyzopertha dominica, select rough rice kernels with cracked hulls for reproduction. J. Insect Sci. 12(38), 7 pp.
PDF	Athanassiou, C.G., F.H. Arthur, and J.E. Throne. 2011. Efficacy of layer treatment with methoprene for control of Rhyzopertha dominica (Coleoptera: Bostrychidae) on wheat, rice and maize. Pest Manag. Sci. 67: 380-384.
PDF	Athanassiou, C.G., F.H. Arthur, N.G. Kavallieratos, and J.E. Throne. 2011. Efficacy of pyriproxyfen for control of stored-product psocids (Psocoptera) on concrete surfaces. J. Econ. Entomol. 104: 1765-1769.
PDF	Athanassiou, C.G., F.H. Arthur, N.G. Kavallieratos, and J.E. Throne. 2011. Efficacy of spinosad and methoprene, applied alone or in combination, against six stored-product insect species. J. Pest Sci. 84: 61-67.
PDF	Perez-Mendoza, J., J.F. Campbell, and J.E. Throne. 2011. Influence of age, mating status, sex, quantity of food, and long-term food deprivation on red flour beetle (Coleoptera: Tenebrionidae) flight initiation. J. Econ. Entomol. 104: 2078-2086.
PDF	Perez-Mendoza, J., J.F. Campbell, and J.E. Throne. 2011. Effects of rearing density, age, sex, and food deprivation on flight initiation of the red flour beetle (Coleoptera: Tenebrionidae). J. Econ. Entomol. 104: 433-451.
PDF	Athanassiou, C.G., F.H. Arthur, and J.E. Throne. 2010. Effects of short exposures to spinosad-treated wheat or maize on four stored-grain insects. J. Econ. Entomol. 103: 197-202.
PDF	Athanassiou, C.G., F.H. Arthur, and J.E. Throne. 2010. Efficacy of methoprene for control of five species of psocids (Psocoptera) on wheat, rice, and maize. J. Food Prot. 73: 2244-2249.
	Athanassiou, C.G., F.H. Arthur, J.E. Throne, G.P. Opit, M.M. Hasan, M.J. Aikins, T.W. Phillips, and N.G. Kavallieratos. 2010. Efficacy of insecticides for control of stored-product psocids. In M.O. Carvalho et al. (Eds.), Proceedings of the 10th International Working Conference on Stored Product Protection, 27 June to 2 July 2010, Estoril, Portugal. Julius Kühn-Institut, Berlin, Germany. pp. 805-814. (Link to article *)
PDF	Athanassiou, C.G., G.P. Opit, and J.E. Throne. 2010. Influence of commodity type, percentage of cracked kernels, and wheat class on population growth of stored-product psocids (Psocoptera: Liposcelidae). J. Econ. Entomol. 103: 985-990.
	Flinn, P.W., J.F. Campbell, J.E. Throne, and B. Subramanyam. 2010. Simulation model of the red flour beetle in flour mills. In M.O. Carvalho et al. (Eds.), Proceedings of the 10th International Working Conference on Stored Product Protection, 27 June to 2 July 2010, Estoril, Portugal. Julius Kühn-Institut, Berlin, Germany. pp. 953-955. (Link to article *)
PDF	Guedes, N.M.P., R.N.C. Guedes, J.F. Campbell, and J.E. Throne. 2010. Contest behaviour of maize weevil larvae when competing within seeds. Anim. Behav. 79: 281-289.
PDF	Opit, G.P., J.E. Throne, and M.E. Payton. 2010. Reproductive parameters of the parthenogenetic psocid Lepinotus reticulatus (Psocoptera: Trogiidae) at constant temperatures. Environ. Entomol. 39: 1004-1011.
	Opit, G.P., S.G. Gautam, B.A. Aminatou, and J.E. Throne. 2010. Ecological studies of the psocids Liposcelis brunnea, L. rufa, L. pearmani, and Lepinotus reticulatus. In M.O. Carvalho et al. (Eds.), Proceedings of the 10th International Working Conference on Stored Product Protection, 27 June to 2 July 2010, Estoril, Portugal. Julius Kühn-Institut, Berlin, Germany. pp. 173-179. (Link to article *)
PDF	Phillips, T.W., and J.E. Throne. 2010. Biorational approaches to managing stored-product insects. Annu. Rev. Entomol. 55: 375-397.
	Throne, J.E. 2010. Overview of North American stored product research. In M.O. Carvalho et al. (Eds.), Proceedings of the 10th International Working Conference on Stored Product Protection, 27 June to 2 July 2010, Estoril, Portugal. Julius Kühn-Institut, Berlin, Germany. pp. 42-49. (Link to article *)
PDF	Throne, J.E., and R.T. Arbogast. 2010. A computer model for simulating population development of the Indianmeal moth (Lepidoptera: Pyralidae) in stored corn. J. Econ. Entomol. 103: 1503-1507.
PDF	Athanassiou, C.G., F.H. Arthur, and J.E. Throne. 2009. Efficacy of grain protectants against four psocid species on maize, rice and wheat. Pest Manag. Sci. 65: 1140-1146.
PDF	Athanassiou, C.G., F.H. Arthur, and J.E. Throne. 2009. Efficacy of spinosad in layer-treated wheat against five stored-product insect species. J. Stored Prod. Res. 45: 236-240.
PDF	Athanassiou, C.G., F.H. Arthur, G.P. Opit, and J.E. Throne. 2009. Insecticidal effect of diatomaceous earth against three species of stored-product psocids on maize, rice, and wheat. J. Econ. Entomol. 102: 1673-1680.
PDF	Flinn, P.W., G.P. Opit, and J.E. Throne. 2009. Predicting stored grain insect population densities using an electronic probe trap. J. Econ. Entomol. 102: 1696-1704.
PDF	Nowaczyk, K., A. Obrepalska-Steplowska, M. Gawlak, J.E. Throne, P. Olejarski, and J. Nawrot. 2009. Molecular techniques for detection of Tribolium confusum infestations in stored products. J. Econ. Entomol. 102: 1691-1695.
PDF	Opit, G.P., and J.E. Throne. 2009. Population growth and development of the psocid Liposcelis brunnea (Psocoptera: Liposcelididae) at constant temperatures and relative humidities. J. Econ. Entomol. 102: 1360-1368.
PDF	Opit, G.P., J.E. Throne, and P.W. Flinn. 2009. Temporospatial distribution of the psocids Liposcelis entomophila and L. decolor (Psocoptera: Liposcelididae) in steel bins containing wheat. J. Econ. Entomol. 102: 1369-1376.
PDF	Opit, G.P., J.E. Throne, and P.W. Flinn. 2009. Evaluation of five sampling methods for the psocids Liposcelis entomophila and L. decolor (Psocoptera: Liposcelididae) in steel bins containing wheat. J. Econ. Entomol. 102: 1377-1382.
PDF	Opit, G.P., J.E. Throne, and P.W. Flinn. 2009. Sampling plans for the psocids Liposcelis entomophila and Liposcelis decolor (Psocoptera: Liposcelididae) in steel bins containing wheat. J. Econ. Entomol. 102: 1714-1722.
	Arthur, F.H., J.E. Throne, and Y. Chanbang. 2008. Combination treatments with diatomaceous earth and methoprene to control Rhyzopertha dominica, the lesser grain borer, in stored rough rice. Contribution for Integrated Management of Stored Rice Pests (handbook). pp. 260-268.
PDF	Chanbang, Y., F.H. Arthur, G.E. Wilde, and J.E. Throne. 2008. Control of Rhyzopertha dominica in stored rough rice through a combination of diatomaceous earth and varietal resistance. Insect Sci. 15: 455-460.
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