Progress 10/01/06 to 10/01/11
Outputs
OUTPUTS: A number of experiments were conducted in the laboratory, greenhouse, and field to characterize various aspects of the biology of pestiferous rice insects, including the rice water weevil, the rice stink bug, and stem borers. Over 20 small-plot and field experiments evaluated various methods for controlling these pests. Results were conveyed to rice extension personnel, who in turn disseminated results and revised recommendations (e.g., about planting dates and insecticide use) to growers via talks and articles in the trade journals, newsletters, etc. Four papers were published in refereed journals, a number of technical reports were published in the Rice Research Station Annual Report, and an article was published in Louisiana Agriculture. PARTICIPANTS: Mike Stout (PI), Jason Hamm, Marty Frey, Srinivas Lanka, Bryce Blackman, Jaspreet Sidhu, Anna Meszaros, Ray McClain, X. Sha, Rogers Leonard and Natalie Hummel, LSU AgCenter; Marco Cosme, University of Berlin; Bill Rice, USDA. TARGET AUDIENCES: IPM practitioners, rice/crawfish producers and consultants, entomologists interested in areas of plant resistance, pest management, rice entomology, chemical ecology PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Basic and applied biological information was improved for existing and emerging rice invertebrate pests, including mosquitoes. High levels of injury by rice water weevil adults induced resistance to subsequent oviposition by rice water weevils. A method was developed to directly inoculate rice plants with rice water weevil larvae. Applications of jasmonic acid did not stimulate plant resistance to rice water weevils in field trials. Further confirmation of the phenomenon in which sugarcane borer oviposition leads to increased resistance of rice plants to subsequent sugarcane borers was obtained. Aquatic invertebrates did not suppress rice water weevil populations in small cage studies. Rice stink bug adults were repelled by metathoracic gland secretions at high concentrations, but were attracted at lower concentrations; significant attraction of females to male dorsal abdominal gland secretions was observed. Phenylpropanoid compounds were found to have divergent effects on the growth of sugarcane borers and fall armyworm. Small-plot and commercial evaluations of insecticidal seed treatments continued to show that these insecticides give adequate to excellent control of rice water weevils, with Dermacor X-100 consistently providing greater control than Cruiser in small-plot studies and commercial-scale demonstrations. Results from small-plot studies have been used to help justify registration of these seed treatments and Nipsit Inside. Granular dinotefuran and foliar clothianidin were effective in water-seeded rice, and cooperation with industry and regulatory agencies will continue to support registration of these active ingredients. Cruiser seed treatment was found to stimulate germination and seedling growth of rice under stress conditions, and greenhouse studies of this phenomenon have been initiated. Early planting and shallow flooding were somewhat effective at reducing rice water weevil populations, and these practices have been incorporated into grower recommendations. Insecticides, shallow flooding, and varietal resistance were compatible tactics, allowing integration of these tactics in the future. Continued progress in elucidating pathways of induced resistance in rice may lead to the development of strategies for enhancing rice resistance to weevils. The neonicotinoid insecticide 'Tenchu' was found to be as effective as pyrethroids against the rice stink bug in small-plot studies and demonstration trials. Oviposition preference and larval performance of sugarcane borers on commercial rice varieties were associated observations pointing to a common causal basis. Dermacor X-100 seed treatments reduced survival of sugarcane borers on rice.
Publications
- Meszaros, A, J.M. Beuzelin, M.J. Stout, P.L. Bommireddy, M.R. Riggio, and B.R. Leonard. 2011. Jasmonic acid-induced resistance to the fall armyworm, Spodoptera frugiperda, in conventional and transgenic cottons expressing Bacillus thuringiensis insecticidal proteins. Entomologia Experimentalis et Applicata 140: 226-237.
- Cosme, M., M.J. Stout, and S. Wurst. 2011. Effect of arbuscular mycorrhizal fungi (Glomus intraradices) on the oviposition of rice water weevil (Lissorhoptrus oryzophilus). Mycorrhiza 21:651-658.
- Stout M.J., D. Michael Jackson, Louis S. Hesler, Marion O. Harris, Lee French, Nora L.V. Lapitan, James A. Reinert, and Anna-Maria Botha-Oberholster. 2009 (published in early 2011). International Plant Resistance to Insects (IPRI), Nineteenth Biennial Workshop, 28-31 March 2010, Charleston SC. J. Agric. Urban Entom. 26: 107-134.
- Stout, M.J., N. Hummel, J. Hamm, and M.J. Frey. 2010. Rice insect control studies, 2010: Overview of program. Ann. Res. Rpt., Rice Res. Stn., LSU Agricultural Center 102: 263-264.
- Stout, M.J., J. Hamm, M.J. Frey, and N. Hummel. 2010. Comparison of clothianidin and other seed treatments against the rice water weevil in drill-seeded rice, 2010. Ann. Res. Rpt., Rice Res. Stn., LSU Agricultural Center 102: 265-266.
- Stout, M.J., J.C. Hamm, M.J. Frey, and N. Hummel. 2010. Evaluation of foliar insecticides against the rice stink bug, 2010. Ann. Res. Rpt., Rice Res. Stn., LSU Agricultural Center 102: 265-266.
- Hummel, N., Stout, M.J., A. Meszaros, J. Beuzelin, D. Burns, B. Courville, G. Daniels, V. Deshotel, K. Fontenot, M. Frey, and S. Gauthier. 2010. Rice water weevil management demonstration in commercial rice fields in Louisiana, 2010. Ann. Res. Rpt., Rice Res. Stn., LSU Agricultural Center 102: 269-270.
- Stout M.J., Hummel N.A., Frey M.J. and Rice W.C. 2011. The impacts of planting date on management of the rice water weevil in Louisiana rice. The Open Entomology Journal. 5: 1-9.
- Stout, M.J., N.A. Hummel, S. Lanka, J.C. Hamm, A. Meszaros, W.R. McClain, and G.W. Barbee. 2011. New tactics for managing rice water weevils in Louisiana rice and making rice fields safe for crawfish. Louisiana Agriculture, Summer 2011, 11-13.
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Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: Recommendations to growers were changed in light of these data. Relevant sections in LSU AgCenter technical publications such as Rice Varieties and Management tips and Rice Production handbook were revised. The results of small-plot and commercial-scale insecticide evaluations were communicated to growers by a variety of traditional and electronic media. Data from this project have helped justify registration of two new insecticidal seed treatments-- Dermacor X-100 (active ingredient, chlorantraniliprole, DuPont Crop Protection) and Cruiser Maxx (active ingredient, thiamethoxam, Syngenta Crop Protection). PARTICIPANTS: Michael J. Stout, lead PI, Department of Entomology, LSU AgCenter. Co-Pis, Wayne Kramer (no longer with LSU AgCenter), and Natalie Hummel, LSU AgCenter. TARGET AUDIENCES: Entomologists, mosquito biologists, agricultural scientists, rice producers, extension personnel. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Insects can cause severe yield losses in rice. For example, work done in small plots and in commercial fields suggests that statewide yield losses from the rice water weevil would approach 10%, if effective insecticides were not available. The use of insecticides remains the primary means of controlling arthropod pests, but alternatives to insecticides are needed to reduce costs, improve sustainability, and minimize environmental impacts. Data from insecticide evaluations have been used to justify registration of new insecticides and to develop recommendations for the effective use of insecticides in commercial rice fields. The insecticidal seed treatment, NipsitInside (active ingredient, clothianidin, Valent U.S.A. Corporation) is likely to be introduced for rice water weevil management in the next few years. These seed treatments represent effective alternatives to the variety of pyrethroid insecticides (Karate, Mustang Max, Declare, etc.) that have been available for use against the rice water weevil for over 10 years. Dr. Hummel coordinated a series of demonstration trials in commercial fields to compare the effectiveness of commercially available insecticides against the rice water weevil. Over the past decade, the Entomology Project has demonstrated that several cultural practices, such as early planting, delayed flooding, and shallow flooding, can reduce the impacts of rice water weevils in rice, and revised recommendations were developed and communicated to growers based on this work. Small cage studies provided evidence that predatory aquatic invertebrates may play a role in regulating rice water weevil densities in rice. Greenhouse studies were continued to compare the resistance of rice varieties released over the past 100 years by the LSU AgCenter against the rice water weevil. Results of these experiments indicate that breeding for improved yield and quality has been accompanied by a slight increase in susceptibility to the rice water weevil. The relationship of tillering capacity and tolerance of rice lines to rice water weevil injury was again investigated, but results have not been analyzed. Differences in the susceptibility of commercial varieties to the sugarcane borer were evaluated. Preliminary data from greenhouse studies showed that early feeding by rice water weevil adults and/or larvae may induce resistance to later infestation by weevils. Oviposition by sugarcane borer adults was found to induce resistance to subsequent borer oviposition. The interactive effects of salt stress and thiamethoxam on the rice water weevil were investigated.
Publications
- Hummel N.A. and Stout M.J Cruiser vs. Dermacor: comparing rice insecticide seed treatments for insect control in Louisiana rice. Mar/Apr: 18-19. FarmGate Mid-South. March 2010.
- Hummel N.A. and Stout M.J. 2010. Rice water weevil control with Dermacor X-100 seed treatment, 2009. Arthropod Management Test, Volume 35. F36.
- Hummel N.A. and Stout M.J. 2010. Rice water weevil control with Clothianidin seed treatment, 2009. Arthropod Management Test, Volume 35. F35.
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: Evaluations of insecticides for use against the rice water weevil and rice stink bug continued. Over 15 separate insecticide evaluations were conducted. These experiments confirmed the efficacy of insecticidal seed treatments (active ingredients: thaimethoxam, chlorantraniliprole, and clothianidin) in drill-seeded rice. Pre- and post-flood applications of clothianidin and granular dinotefuran were found to be effective against rice water weevils in water-seeded rice. Neonicotinoids were found to be effective against the rice stink bug. The insecticides being considered as alternatives to the pyrethroids for rice water weevil control generally caused less mortality of non-target invertebrates (Notonectidae, Corixidae, and mayflies) than did pyrethroids, and use of clothianidin as a seed treatment resulted in lower concentrations of the insecticide in water samples than did use of clothianidin as a pre-flood foliar spray. Likewise, the newer insecticides had less affect on crawfish confined to test plots than did the pyrethroids. In monitoring of commercial fields, the performance of Dermacor was excellent (90-95% reduction in weevil densities), and the pyrethroids performed as expected (70 to 80% control). The acute toxicity of Rynaxypyr to crawfish was evaluated in water-exposure and seed-feeding experiments, and the insecticide was shown to be orders of magnitude less toxic than pyrethroids. Data from a date of planting study were analyzed and showed that early planting is associated with reduced weevil populations, reduced yield losses from weevils, and improved efficacy of foliar insecticides. In a study employing combinations of a cultural practice (shallow flooding), resistant varieties, and insecticides for rice water weevil management showed that these tactics are compatible with one another. Greenhouse studies were conducted to compare the resistance of rice varieties released over the past 100 years by the LSU AgCenter against the rice water weevil. Results of these experiments indicate that breeding for improved yield and quality has been accompanied by a slight increase in susceptibility to the rice water weevil. In a small-plot field study, tolerance of rice lines and varieties to rice water weevil injury was positively correlated with tillering capacity of the lines/varieties. Differences in the susceptibility of commercial varieties to the sugarcane borer were evaluated. Preliminary data from a multi-state collaboration suggest that heavy use of pyrethroids against the rice water weevil may be leading to insecticide resistance. A mark-recapture study showed that efficiency of sweep net sampling for rice stink bugs is about 15%. In a small-plot field trial, a seed treatment of Rynaxypyr was found to reduce stem borer densities. Herbivore-induced resistance in rice to sugarcane borers was investigated in a series of experiments. The effects of salt stress on the susceptibility of rice to the rice water weevil was also investigated. PARTICIPANTS: Michael Stout, Professor, Dept. of Entomology, LSU AgCenter Natalie Hummel, Assistant Professor, Dept. of Entomology, LSU AgCenter Wayne Kramer, Associate Professor, Dept. of Entomology, LSU AgCenter TARGET AUDIENCES: Rice/crawfish farmers , IPM specialists, consultants, mosquito abatement and public health professionals, entomologists and other scientists interested in pest management and plant resistance PROJECT MODIFICATIONS: Nothing significant to report
Impacts
Results of commercial sampling of rice fields show that the average density of weevil larvae in commercial rice fields is approximately 12 larvae per core. Prior research indicates that 12 larvae per core translates to over 5% yield loss, meaning that economic losses due to the rice water weevil in Louisiana would exceed 5 million dollars annually if effective managment practices were not in place. Data from insecticide evaluations were used to help justify registrations of alternative insecticides against the rice water weevil. A section 18 registration was granted to Dermacor for the 2009 growing season, and a Section 3 registration was granted to thiamethoxam in 2009 for the 2010 growing season. Results from research on cultural practices was used to refine recommendations made to growers. Work on crawfish and non-target toxicity was communicated to growers, and increasing use of new insecticdes should result in fewer cases of pyrethroid drifts into crawfish ponds and subsequent mortality. Work on plant resistance was used to justify the initiation of a breeding program for development of weevil-resistant varieties. Several collaborations were developed in 2009 to jointly investigate molecular aspects of induced resistance in rice. Overall, the management programs for the rice water weevil and rice stink bug ahve been improved to make them more diverse and environmentally friendly.
Publications
- Stout, M. and J. Davis. 2009. Keys to the increased use of host-plant resistance in integrated pest management. Pgs. 163-182. In Peshin, R. and A.K. Dhawan (eds.), Integrated Pest Management: Innovation-Development Process. Springer.
- Stout, M.J., D. Harrell, K.V. Tindall, and J. Bond. 2009. The Impacts of Seeding Rate on the Interaction between Rice and the Rice Water Weevil. Journal of Economic Entomology 102(5):1837-1845.
- Barbee, G. C. and M.J. Stout. 2009. Comparative acute toxicity of neonicotinoid and pyrethroid insecticides to nontarget procambarid crayfish associated with rice-crayfish crop rotations. Pest Management Science 65: 1250-1256.
- Stout, M.J., M.R. Riggio, and Y. Yang. 2009. Direct Induced Resistance in Rice, Oryza sativa, to the Fall Armyworm, Spodoptera frugiperda. Environmental Entomology 38: 1174-1181.
- Bhonwong, Anongnut, M.J. Stout, J. Attajarusit, and P. Tantasawat. 2009. Defensive role of tomato polyphenol oxidases agains cotton bollworm (Helicoverpa armigera) and beet armyworm (Spodoptera exigua). Journal of Chemical Ecology 35: 28-38.
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: The outcomes of this project described in the next section have resulted or will result in the following outputs: 1) Results of insecticide efficacy testing are being used to justify the registration of new insecticides against the rice water weevil and rice stink bug 2) Recommendations for the use of alternative insecticides against the rice water weevil and rice stink bug, when and if the alternative insecticides are registered 3)Recommendations that will allow increased reliance on cultural practices for management of the rice water weevil, and reduced reliance on insecticides 4) Identification of insecticides and use patterns that will reduce the impact of pest management on non-target organisms, including crawfish 5) Initiation of a breeding program for rice resistance to the rice water weevil PARTICIPANTS: Michael Stout, Professor, LAES Wayne Kramer, Associate Professor, LAES Dennis Ring, Professor, LCES Members of Multi-State Research Project S-1029 TARGET AUDIENCES: Rice producers Mosquito abatement personnel Scientists interested in rice IPM, mosquito biology/control PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Efforts were continued to evaluate insecticides against rice water weevil and rice stink bugs. Neonicotinoid seed treatments (thiomethoxam, clothianidin), an anthranilic diamide seed treatment (rynaxypyr), and neonicotinoid granules (dinotefuran) and liquid formulations (clothianidin) were found to be effective against rice water weevils, and liquid formulations of clothianidin, thimethoxam, and dinotefuran were found to be effective against rice stink bugs. All of these products may be viable alternatives to pyrethroids. Questions still remain about optimal rates, formulations and timings for these insecticides, especially in water-seeded rice. Another major focus was evaluating these pyrethroid alternatives for compatibility with crawfish production. Field tests with caged crawfish suggest that these newer insecticides will be more compatible with crawfish production and softer on other aquatic arthropods. All of the newer insecticides were found to have lower acute toxicities toward crawfish than the pyrethroids. The oviposition preferences of sugarcane borers for common commercial rice varieties were tested and substantial differences were found. Greenhouse experiments also showed that rice infested with borer larvae were more resistant to subsequent attack by borers. Research on induced resistance in rice was continued. A method to induce resistance with fall armyworms was developed, and armyworm feeding was shown to induce resistance to armyworms and weevils. Small rice plots treated with a chemical elicitor of resistance were shown to be more resistant to rice water weevils. Multi-year tests of the cultural practices of seeding rate and planting date were concluded in 2008. Results from the seeding rate test showed that rice seeded at low rates is more vulnerable to weevil injury. Planting date experiments showed that weevil populations were lower and efficacies of insecticides were greater in early-planted fields than late-planted fields. Finally, small-plot experiments demonstrated that populations of weevils were lower in shallow-flooded plots than in normally flooded plots. Additional replicated tub trials on mosquito larvicides were conducted in 2008 at the St. Gabriel Research Farm. The primary larvicide tested was Dimilin (Diflubenzuron) at 250ppb and 1 ppm. The tablet form of the product (Bi-Larv 2) was utilized in 50 gallon plastic tubs. Field collected water samples collected at 7 day intervals from the tubs were bioassayed in the laboratory against early instar Culex mosquito larvae and observations on larval mortality recorded daily for 4 days. Results showed that both high and low tested rates of Diflubenzuron resulted in 100% mortality within 7 days post treatment. Overall toxicity of the 250 ppb treatments declined after 14 days and by 21 days the overall mortality was only 26 %. The high rate (1 ppm) still showed 90% mortality at 21 days and 76% at 28 days. Colonization rates of non target insects were also recorded in all tubs. Populations of colonized non-target insects in the treatment tubs were not significantly lower in Dimilin treated tubs than in control tubs 31 days post treatment.
Publications
- No publications reported this period
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: This project represents a multi-state collaboration between scientists interested in management of arthropod pests of rice and scientists interested in biology and management of mosquitoes in rice field habitats. Participants in this multi-state project meet once a year to share results and develop collaborations. Results are disseminated to interested clientele by traditional means. The website for this multistate project can be found at http://nimss.umd.edu/homepages/saes.cfm?trackID=8396
PARTICIPANTS: Michael Stout and Wayne Kramer, LAES, Department of Entomology, LSU
Impacts
Arthropod pests are important constraints on rice yields in Louisiana. The most important early season pest of rice in Louisiana is the rice water weevil (rww). A new analysis of yield losses in 17 insecticide trials conducted from 2002-2005 supported prior data showing that feeding by rww larvae is associated with losses of nearly 1% per larvae, and that yield losses in excess of 25% are not uncommon. Other pests of importance are the rice stink bug (the most important late-season pest), a complex of stem-boring Lepidopterans, and the fall armyworm. Crawfish and rice are co-cultivated in many rice fields in Louisiana; thus, the impact on crawfish of insecticides used in rice must also be understood. In addition, flooded rice fields represent an important potential habitat for immature mosquitoes. Some of these mosquito species are important from both a public health perspective, because they can vector diseases, and from an economic perspective, because they are
nuisance species and/or because they vector diseases of veterinary importance. It is thus also important to understand how important rice fields are as breeding grounds for mosquitoes and to understand how crop production practices and pest management practices impact mosquitoes in rice. The current rww program relies heavily on applications of pyrethroids to kill adult rww. Several experiments conducted in 2007 and in previous years have highlighted the problems associated with pyrethroid use in rice; namely, single applications of pyrethroids are insufficient to control rww in late-season rice, and use of pyrethroids can result in high levels of crawfish mortality. A number of trials were conducted in 2007 to evaluate the efficacy of several potential pyrethroid alternatives against the rww and to evaluate the toxicity of these pyrethroid alternatives to crawfish. All of the potential pyrethroid alternatives provided control of rww populations as good as, or better than, that
typically provided by pyrethoid applications. Moreover, experiments using caged crawfish in rice plots showed that the potential pyrethroid alternatives are more compatible with crawfish production than currently registered insecticides A field tub (50 gallon) experiment demonstrated the efficacy of diflubenzuron against mosquito larvae. A manuscript is in preparation which describes the impact on rice-field mosquitoes of applications of the broad-spectrum pyrethroid insecticide Karate. The proper foundation of effective management programs is a thorough understanding of pest biology. Preliminary work was conducted to identify volatile organic compounds that attract stink bugs to rice fields and to identify volatiles used by stink bugs as defenses. In addition, research was continued to better understand the oviposition preference of sugarcane borers. In several greenhouse experiments, it was shown that female sugarcane borers prefer to oviposit on rice plants that are not infested
with conspecific larvae over plants that are infested with conspecific larvae.
Publications
- No publications reported this period
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