Duration: 10/01/2006 to 09/30/2011

Administrative Advisor(s):

NIFA Reps:

Non-Technical Summary

Statement of Issues and Justification

A. The need for this project as identified by stakeholders. Invasive and endemic arthropod pests make it essential to develop integrated pest management (IPM) tactics for rice-growing states. Such tactics must meet both crop production requirements and the need to reduce the populations of mosquitoes that breed in rice fields. The rice crop is of great economic importance in many U.S. regions, especially the southern states and California. 3.3 million acres of rice were planted in the U.S. in 2005. Rice is staple crop for half of the world's people, and 40% of the U.S. rice crop is exported. The U.S. was projected to be the third largest rice exporter in the world for 2005. Ensuring good rice harvests therefore promotes economic stability and food security at home and abroad. Rice has vast economic value in excess of the crop price ($1.64 billion for milled rice in 2004, U.S. Census Bureau), because this commodity supports numerous industries (e.g. human and animal food manufacturers and retailers). Rice fields provide essential habitat for wildlife, especially migratory waterfowl. However, ricelands also pose the greatest challenge for mosquito control districts in many rural areas. Riceland mosquitoes can transmit a variety of endemic and potentially invasive diseases that threaten the health of humans, livestock, and wildlife in rural areas.

The rice crop is under continual threat from resident and invasive arthropod pests. Crop losses due to arthropod pests can range up to 30%. Without scientific research on how to control these pests, growers could be faced with serious economic losses. In addition to pests that cause crop damage, there are serious issues with disease-bearing insects emanating from rice fields. Species of mosquitoes found in rice fields are some of the most efficient vectors of West Nile Virus, St. Louis Encephalitis virus, Venezuelan Equine Encephalitis virus, anaplasmosis (in cattle) and other pathogens, including the causative agents of invasive diseases (e.g. malaria, dengue fever, Japanese Encephalitis). Thus, it is imperative to perform research that identifies effective, safe, and economical IPM programs for crop pests and mosquitoes in rice fields. Control methods used by rice growers and mosquito control personnel must be coordinated, because of the ongoing threats of insecticide resistance in pests and of biological control disruption. New pest control methods are continually being developed (by our group and others). Growers and public health agencies need to know whether these products are safe and effective, and whether they affect mosquito populations either positively or negatively. Agricultural pesticides, herbicides, and production practices have the potential to either reduce mosquito populations or cause dangerous outbreaks, depending on how these techniques affect beneficial predators and resources for mosquitoes. Research is also needed to understand the biology, ecology and disease-vectoring capacity of the mosquitoes that breed in rice and associated wetlands, and to develop and test new methods of mosquito control.

Much of our work is driven by stakeholders. Our members frequently receive research requests from growers, the crop protection industry, vector abatement personnel, other public health agencies and wetland managers. Members of our group are in close collaboration, and in many cases act as liaisons between the resource managers (rice and wetlands) and the protection industries (agrichemical and vector abatement).

National and regional priorities addressed in this project include enhancing IPM in an important crop (SAAESD Programmatic Goals 4D, 4F), and reducing human and livestock health concerns (through mosquito management) (SAAESD Goals 1 I and 5 C, F). Rice fields are intrinsically multiple-use areas (SAAESD Goal 4 B,C) because rice fields function as seasonal wetlands that support numerous aquatic animals and birds (review: Lawler 2001). Much of this project is targeted toward helping growers identify which pest control practices are effective, yet safe for the biota. A CRIS search on combinations of the keywords rice, pest, arthropod, insect and mosquito showed that this is the only current or pending project addressing management of arthropod pests of rice, mosquito management in rice, or integrating strategies for managing multiple arthropod pests.

B. Importance and extent of the problem. Arthropod pests of rice can cause yield losses of up to 30% or more. Each year, mosquito-borne disease kills or disables hundreds of people in the US. There were 2949 cases of West Nile Fever in the USA in 2005 (116 deaths). Outbreaks of other viruses also occur (e.g. an average of 128 cases of St. Louis Encephalitis per year). New invasive crop pests and vector-borne diseases continually threaten our borders. Vector-borne diseases also threaten livestock. Uncontrolled mosquitoes can reduce property values, cause labor problems, and have negative effects on the tourist industry.

If this project were not done, fewer integrated pest management methods would be developed and tested in the field, and rice pest management would not be integrated with mosquito management. Growers and mosquito abatement personnel would not know which methods are most effective against pests, and which are safest for the environment, including beneficial predators that feed on rice pests and mosquitoes. This could lead to lower rice yields, greater costs of production, and environmental damage. Rice fields and associated wetlands could become a danger to public health if new production techniques were applied in ignorance of their side-effects on mosquito populations.

C. Technical feasibility. Both the plans outlined below and our track records show that this project is technically feasible. Our members have published extensively in the areas to be addressed by this project; please see 'Related, Current and Previous Research'. We will seek out a biostatistician to join our group to facilitate meta-analysis of data.

D. Advantages to performing this research as a multi-state project. Our project requires coordination of experimental designs across states, so that statistical analysis and examination of geographical block effects can meet both the goals of scientific rigor and understanding local variation. One challenge our AES scientists face is that any individual experiment station is limited in the number of experimental fields and techniques, yet several new insecticide formulations, crop varieties, and pests demand testing each year. Most investigators perform large-scale, but low replication studies so that they can show stakeholders outcomes for each new method, under local conditions and at realistic scales. While stakeholders typically find results convincing, it is difficult to make statistical inferences from these limited replication efforts. We anticipate publication of more team-authored papers in the primary literature as a result of this collaboration. Our group has a track record of joint publications (e.g. Dennett et al. 2000, 2003, Stout et al. 2002a, Lawler et al. 2003). In addition, the multi-state format allows us to develop 'rapid response' collaborative research projects that will help minimize damage as new insect pests or vector-borne diseases emerge in any of the rice-growing areas. For example, project scientists were at the forefront of efforts to understand and control Mexican rice stem borer on rice and sugar cane, as it expanded its range in the Southern region during the S-300 project period. This valuable collaborative effort will continue during this new project.

E. Benefits of this research include development of new pest control methods, and testing new insecticide formulations, crop varieties and production techniques. We will discover which methods can provide cost-effective pest control while protecting non-target species and human health. We will add to basic knowledge about crop pest and mosquito biology and ecology. This project will set an example for large-scale, geographically coordinated scientific research. For further benefits, please see 'VI B. Outcomes and Projected Impacts', below.

F. Stakeholders include: Rice growers, rural communities, mosquito and vector control districts, related public health agencies, industries that rely on rice, and pest control industries.

Related, Current and Previous Work

We accomplished the four goals of our prior, related S-300 project, however further work is necessary because of the ever-changing nature of threats from pests, development of new materials to control them, and changes in rice growing practices. Our (abbreviated) goals were to: 1. Determine the best chemical tactics for rice pest and riceland mosquito control, 2. Determine the best non-chemical tactics for rice pest and riceland mosquito control, 3. Develop a database on the bionomics of rice pests, mosquitoes and beneficial aquatics in winter flooded fields and fields with differing straw management regimes, and 4. Research the vector capacity of Anopheles quadrimaculatus for malaria and conduct spatial monitoring for West Nile Virus and St. Louis Encephalitis Virus, and update the database on mosquito distributions and systematics. In addition to meeting these goals, the project resulted in a collaborative Southern Region IPM Grant , 'Development of monitoring tools for the rice water weevil in rice' (Stout, Bernhardt and Way). Highlights are given below.

Goal 1. We developed and tested novel mosquito control methods, including evaluation of the efficacy and cross-resistance spectra of new transgenic strains of insecticidal bacteria that are both effective, and less vulnerable to the evolution of resistance (e.g. Park et al. 2005, Wirth et al. 2001, 2004a,b). Another novel control method was a combined formulation of methylated soy oil and B.t.i. (Dennett et al. 2000). We tested numerous pesticide formulations for effects on crop pests, mosquito populations and beneficial predators (e.g. Stout et al. 2000, Dennett et al. 2003, Nayar and Ali 2003); biological control disruption was an issue for lambda-cyhalothrin and mosquitofish (Lawler et al. 2003). Other tests included less-toxic compounds like Btt and oils against crop pests (not all were effective). Not only did our insecticide tests inform growers, they contributed to the registration of two insecticides against rice water weevil and rice stink bug (gamma-cyhalothrin and cypermethrin), with three other registrations in progress. Work by TAES on etofenprox showed that this material is comparatively safe for crayfish, and this information helped LA farmers to obtain a Section 18 emergency exemption for its use near crayfish and bass ponds. For most substances, effects on non-target organisms depended on the timing of insecticide applications. Pre-flood treatments were much less harmful than mid-season applications. Laboratory tests are underway for WaterSaver Bti (for mosquitoes) and Novaluron, a new insect growth regulator; the upcoming project will include field tests of these and other new formulations (e.g. Azadirachtin).

Goal 2. We made excellent progress in determining non-chemical methods for reducing pest problems. Minimizing pesticide applications decreases damage to the beneficial predators that consume crop pests and mosquitoes. One priority was identifying rice cultivars resistant to rice water weevil. We screened numerous cultivars and genotypes, and discovered differences between cultivars of up to 5x in pest numbers and crop damage. This information has been made available to growers and the scientific community (e.g. Stout et al. 2001, Stout and Riggio 2003, Zou et al. 2004b and various technical reports). We have shown that early planting and delaying permanent flood can reduce the need for pesticide treatments (e.g. Stout et al. 2002 a, b).

Goal 3. We made significant advances in understanding the basic biology and dynamics of rice water weevil and other crop pests, including identifying non-crop hosts of the weevil (e.g. Tindall et al. 2003, Way et al. 2004, Saito et al. 2005) and creating a model for weevil emergence and development (Zou et al. 2004a). We initiated research on controlling chinch bug and the invasive Mexican rice stem borer (e.g. Mejia-Ford et al. 2004, Reay-Jones et al. 2005). For the latter, economic benefits are $0.5 million/yr and increasing as the borer's range extends. Winter flooding and on-site straw decomposition were found to boost populations of both mosquitoes and beneficial predators relative to burning straw (e.g. Lawler and Dritz 2005). Conversely, reducing wetland vegetation reduced mosquito populations (Thullen et al. 2002, Jiannino and Walton 2004), and freshly dried mown vegetation was found to foster more mosquitoes than weathered vegetation (Knight et al. 2003, Walton 2003).

Goal 4. Work is ongoing for goal 4, determining the vector capacity of various mosquitoes. We successfully initiated spatial monitoring for mosquito-borne diseases (e.g. Kent et al. 2001).

Objectives

1. To advance basic and applied biological research on existing and emerging rice invertebrate pests, including mosquitoes.
   
2. To determine the most effective control methods for rice pests while maintaining environmental quality compatible with the needs of society.
   
3. To develop strategies to maintain the effectiveness of current pest-control techniques.
   

Methods

Objective 1. To advance basic and applied biological research on existing and emerging rice invertebrate pests, including mosquitoes. Members of our group are leaders in advancing knowledge of the basic biology of rice crop pests and mosquitoes (e.g. Stout et al. 2002b, Hix et al. 2003, Mejia-Ford et al. 2004, Zou et al. 2004a,b, Saito et al. 2005; Bosworth et al. 1998, Peck and Walton 2005, Lawler and Dritz 2005). We will address crucial information gaps about the ecology and biology of crop pests and mosquitoes, especially recent invaders. This information is central to developing effective control strategies that minimize chemical use. A. Crop Pests Crop pests of particular concern include rice water weevil (Lissorhoptrus oryzophilus), rice stink bug (Oebalus pugnax ), armyworms, and grape colaspis (Colaspis brunnea), plus recent invaders like Mexican rice borer and sugarcane borer. Rice Water Weevil (RWW). RWW is a devastating early-season pest. Its overwintering behavior is not known in enough detail to develop control strategies targeting this stage. The contribution of various microhabitats (e.g. leaf accumulations, grasses, other weeds) to its prevalence is unknown. Recent observations suggest that infestations result from crawling from weedy levees, rather than flights from scattered overwintering sites. Increased knowledge in this area could restrict chemical treatments to localized sites instead of to the flooded fields. Methods: Investigators will select numerous potential sites for RWW wintering. Berlese funnels will separate RWW from plant materials. Regression analysis will be used to correlate weevil abundances with microhabitats. AAES, CAES and LAES will coordinate studies to include similar microhabitats, to discover geographic patterns. Reproductive biology will be investigated relative to sexual and parthenogenetic females. CAES will use a mark-recapture method to track movement of RWW adults into flooded rice fields. Results will help growers to assess wintering sites and to identify at-risk fields. Rice Stink Bug. This insect has cost growers $15 - 30 million in some southern states. Better methods are needed to predict early-season abundances and movement among crops. Early-season stink bugs rely on weeds, oats and wheat. The alternate hosts available to rice stink bugs differ between LA and AK. Therefore early stages of the research will be specific to research stations, but collaboration is planned for later stages. Methods: AAES will mark adult stink bugs in wheat fields in June. In June and July, AAES will sample plant hosts near wheat and oat fields to assess movement, using a grid system and GPS. Results will indicate the importance of the grain fields to wintered adults, and will quantify dispersal. New sampling methods and revised economic injury levels will be developed. This will help identify at-risk fields and allow growers to control the bugs efficiently. LAES will conduct experiments to identify attractants of rice stink bugs, either pheromones or host plant-derived compounds. Attractants can be used to develop improved monitoring tools. Any attractants developed will be used to compare movement of rice stink bugs in states where they are a problem. Armyworm. Several armyworms are emerging as pests in rice (e.g. Spodoptera praefica, Pseudaletia unipuncta). Discovering infestation sources is a critical issue for control. AAES and CAES will address this in complementary ways, with AAES focusing on crops as alternate hosts and CAES focusing on weeds. Both will assess natural biological controls and the relation between population size and crop damage. Methods: AAES: Recent increases in the threshold for treating armyworms in Arkansas wheat may have an impact on pre-flood rice. Researchers will (a) identify which instar of armyworms commonly moves from wheat into rice, (b) assess damage by armyworms in pre-flood rice, (c) develop insecticide treatment thresholds, (d) test biological and reduced risk materials, and (e) study natural biological control of armyworms. Studies will be conducted at the ARREC-Stuttgart and nearby wheat and rice fields. Small rice plots will be used and the insecticide experiments will be a randomized block design with at least 4 replications per material. Collections of larvae in pre-flood rice near wheat fields will be made when armyworms are noted by growers, CES agents, or from detections in our random surveys. Methods: CAES. Research is underway to discover the role of weeds in armyworm outbreaks and to test whether pheromone traps are useful in predicting armyworm numbers. Preliminary results suggest that armyworms were more abundant in weedy fields than those with good weed control. We will quantify caterpillars in replicated plots that contain several weed treatments (e.g. broadleaf weeds, grasses, both kinds of weeds, and weeds removed). A trap method will be developed for use by growers. Armyworm larvae will be monitored for abundance and parasitism rates. We will seek correlations between these factors and agronomic and production factors. The most effective trap methods, cultural controls and insecticides identified by CAES and AAES may be used in wider collaborative work with other states. Grape Colaspis. AAES will assess various chemicals for efficacy on grape colaspis in replicated 5 X 20 ft. plots in drill-seeded rice. The chemicals will generally be those tested by LAES, AAES, CAES, MAES, and TAES for efficacy against RWW. Plots treated with fipronil as a seed treatment will serve as controls. Damage will be recorded weekly from the 2 leaf stage to the 4 leaf stage, and final yields will be quantified. B. Mosquitoes The southern region is at risk for invasion and spread of Dengue fever, which can be spread by both Aedes aegypti and Ae. albopictus. TAES is researching the effects of temperature on the eggs and larval development of both species. Replicated sets of eggs and larvae will be reared at a range of temperatures and humidities typical of the southern region. This information will help mosquito abatement districts set timely inspection and treatment schedules. In addition, TAES will continue its spatial surveys of West Nile Virus activity. LAES will seek to identify oviposition deterrents or attractants from rice fields (e.g. substances emitted by predators). CAES-Riverside will research how water treatment wetland designs affect mosquito production and species composition. Six experimental sites will be divided into two treatments: wetlands designed to enhance denitrification, with decaying organic material spatially restricted, and wetlands designed to promote sedimentation, with long narrow water flow paths and less than 50% emergent vegetation. The former treatment is expected to restrict mosquitoes in space by concentrating their resources in one area, while the latter should promote predatory invertebrates. Treatments will be assessed by: 1. Rearing Cx. tarsalis mosquitoes in situ using floating sentinel cages, in areas expected to be rich and poor in predators. 2. Monitoring mosquito abundance and adult production in replicated locations throughout the wetlands. 3. Quantifying larval mosquito resources. We will use both standard limnological techniques and molecular microbial analysis to associate microbial species composition and diversity with mosquito growth. Objective 2. To determine the most effective control methods for rice pests and mosquitoes while maintaining environmental quality compatible with the needs of society. A. Effects of agricultural insecticides on crop pests and mosquitoes Since 1976, members of our group have been leaders in assessing the efficacy and non-target effects of insecticides used in rice agroecosystems. It is essential to continue providing growers with objective tests of the effectiveness of new materials and existing and to optimize usage. We will test materials on crop pests, beneficial insects and mosquitoes. Trials will include a variety of insecticides (e.g. lambda cyhalothrin, zeta cypermethrin, gamma cyhalothrin, etofenprox, dinotefuran, thiomethoxam, avermectin and azadiractin). Most companies arrange for their products to be tested in multiple states; for example the efficacy of a new granular formulation of etofenprox (Mitsui) against RWW is currently being tested by AAES, CAES, LAES, MAES, and TAES. Similarly, the efficacy of a combination fungicide/ insecticide seed treatment (Syngenta) against RWW and the grape colaspis is being tested by several of our AES. Results of these insecticide screens are shared among project participants. For widespread pests that have similar life histories among states (e.g., rice stink bug, and rice water weevil in all but CA), similar methods will be used for efficacy tests of insecticides in all states. Efficacies are tested in small plots, with plots arranged in a randomized complete block design. Measures are taken to restrict movement of insecticide among plots after flooding. Timings, rates, and application methods are dictated by the insecticide being tested but similar use patterns are employed by all states. The use of similar methods by all participants will allow us to perform a meta-analysis of results to quantify overall efficacy and geographical variation. This type of cooperation among states has been an important factor in obtaining data used to justify registration of new products. Such experiments will provide a holistic assessment of the efficacy and non-target effects of insecticides, including effects on mosquitoes. A study of the insecticide lambda-cyhalothrin is planned for next year and is our prototype. Four of our states (AAES, CAES, TAES, LAES) will establish 3 treated and 3 control sites in rice fields measuring 15 X 5 m, which are isolated using aluminum flashing that is sunk into the substrate to a depth of > 10 cm. Treated sites will receive 0.03 lbs lambda cyhalothrin ai/ac as a preflood application, with the same amount applied again in mid-June. Response variables will be yield, plant damage, density and composition of aquatic insects, and abundance of mosquito larvae. Crop pests will be sampled using methods appropriate to the taxa (e.g. replicated soil cores for rice water weevil immatures; counts for armyworm, grape colaspis, and rice stink bug; typical damage for stem borer). To assess non-target effects and mosquito responses, aquatic insects will be collected weekly for 3 weeks following each treatment, using quadrat samplers. Samplers are 10 gal., bottomless buckets that are quickly pressed into the substrate to trap insects. These are removed via a 10 X 13 cm hand net (mesh size 0.25 mm). Insects are preserved with 70% ETOH and identified to family level. Mosquitoes are sampled with 30 dips of a 350 ml cup-shaped dipper. B. Mosquito Control We have planned research targeting control of adult mosquitoes that emerge from rice fields and associated aquatic habitats, plus important invasive species. KAES will perform laboratory tests of Wolbachia as a biopesticide for mosquitoes. Wolbachia are intracellular bacteria that are estimated to naturally infect up to 28% of mosquito species (Werren et al. 1995, Kittayapong et al. 2000, Ricci et al. 2002,). Wolbachia have excellent potential as biological control agents (Dobson et al. 2002) and as a vehicle for driving desired genotypes into disease vectors (Sinkins and O'Neill 2000, Dobson 2003,). Suppression and gene replacement strategies are based upon the ability of Wolbachia to cause early embryonic death through cytoplasmic incompatibility (CI) (Lassy and Karr 1996). Wolbachia-based insect suppression strategies are similar to that of traditional sterile insect technique, except that CI males are released instead of sterile males. The Wolbachia strategy eliminated a medically important Culex field population in Myanmar (Laven 1967). However, application of this technique to additional mosquito populations has been restricted by an inability to identify appropriate Wolbachia strains. An example is Aedes albopictus, an invasive, important disease vector of multiple arboviruses and filaria (Moore and Mitchell 1997). This mosquito has spread through much of the Southern region. Ae. albopictus field surveys demonstrate that individuals are uniformly superinfected with two Wolbachia types (wAlbA and wAlbB) (Sinkins et al. 1995, Zhou et al. 1998, Kittayapong et al. 2002,). Thus, Wolbachia-based strategies to reduce Ae. albopictus populations will require artificially generated incompatible infection types. Transfer of Wolbachia ('transfection') is accomplished via microinjection of Wolbachia infected cytoplasm in embryos (Boyle et al. 1993, Xi and Dobson 2005). KAES used a transfection technique for Ae. albopictus that segregated the naturally occurring Wolbachia superinfection, resulting in an artificial wAlbB single infection (HTB strain) (Xi et al. 2005). The HTB strain is not useful for applied strategies, but shows that the technique will work. Population suppression will require the release of males that are bidirectionally incompatible with the naturally superinfected Ae. albopictus population (Dobson et al. 2002). Bidirectional incompatibility occurs when different Wolbachia types infect the same host insect population. It results in embryo mortality whenever mating occurs between individuals with differing infection types (Hoffmann and Turelli 1997). Models predict that two or more incompatible Wolbachia types within a panmictic population will quickly reduce to a uniform infection type (Rousset et al. 1991). Releases of incompatible insects into the population prolong the co-occurrence of bidirectionally incompatible infections (Dobson et al. 2002). Since male mosquitoes do not blood feed or transmit disease, large numbers of males may be released. KAES recently generated an artificial Wolbachia infection useful for Ae. albopictus suppression (HTR line). The HTR line is bidirectionally incompatible with both natural infections and the previously generated artificial infection (Xi et al. 2005). Initial trials show that releases of HTR males into laboratory cages of superinfected populations result in reduced egg hatch. KAES will generate additional Wolbachia infected mosquitoes and conduct laboratory experiments to create strategies to suppress important mosquito populations. Area-wide control of mosquitoes is sometimes economically or logistically impracticable. As part of cooperatively funded ARS project #56-6615-5-248, AAES will assess whether perimeter applications of residual insecticides can be used to reduce vector infiltration of areas used by humans (including deployed troops). Replicated small plots will be established and their perimeters will be either treated or untreated with residual insecticide (e.g. Talstar®). CO2 baited mosquito traps placed in each plot will measure vector infiltration. AAES will also continue work to optimize ULV (ultra low volume) applications of insecticides. Vector control agencies often use ULV insecticides in rice-growing areas. Mosquitoes emanating from rice fields frequently seek shelter in adjacent wildlife refuges. Although one-time applications of ULV insecticides were found to have no detectable effects on aquatic invertebrates (Jensen et al. 1999), repeated applications still cause concern because it is unknown whether prolonged use of insecticides could deplete aquatic invertebrates that are important resources for water birds. CAES is quantifying the effects of ULV pyrethroids on aquatic invertebrates. Each year, 3 treated and 3 untreated wetlands will be sampled for invertebrates and zooplankton for 6 weeks, during which time ULV fogs will be applied twice weekly. We will also perform mesocosm tests with wetlands constructed in tanks; these allow us to control water quality. Twelve 1.8 m diameter tanks will contain 30 cm of well water, plus 5 cm of clean dirt and sod. We will quantify the 24 h mortality of 30 caged Daphnia magna and 20 caged Callibaetis mayflies per mesocosm, after 5 and 10 ULV treatments. Lids will protect the 6 control mesocosms on spray nights. Results will promote effective communication between wetland managers and mosquito abatement districts. C. Cultural techniques for pest control Resistant cultivars can decrease the need for insecticides, which saves time, money, protects the environment and preserves beneficial predators (Reay-Jones et al. 2003, Zou et al. 2004b). LAES is characterizing plant traits that allow rice plants to tolerate injury from the rice water weevil. Once the physiological traits that contribute to weevil tolerance are identified, rice lines possessing these traits can be developed. Mexican rice borer emerged as a significant pest of rice in the 1990's (Reay-Jones et al. 2003, 2005), and sugarcane borer was recently discovered to be damaging rice in Arkansas. TAES and LAES are collaborating to develop an I.P.M. system for Mexican rice borer, including resistant cultivar selection, cultural control and establishing economic thresholds for insecticide treatment. TAES and LAES will jointly perform experiments aimed at discovering optimal planting dates to minimize stem borer infestations, and will establish economic injury/treatment threshold levels. Replicated plots will be planted with hybrid or conventional rice varieties in March, April and May. We will quantify whiteheads and both filled and unfilled grains from randomly sampled panicles, and measure plot yields. Results will inform growers of optimal varieties and planting dates. Replicated cage studies will establish economic thresholds for insecticide treatments. This program should minimize insecticide applications, thus conserving natural biocontrol agents of other pests including mosquitoes. In addition, AAES will begin studies of rice resistance to the sugarcane borer, and will also initiate studies of cultural controls, insecticide efficacy, pheromone disruption, and economic thresholds. AAES will evaluate rice lines from Arkansas, Louisiana, Mississippi and Texas for susceptibility to damage by the rice stink bug, using both the Arkansas Rice Performance Trials (ARPT) and the Uniform Regional Rice Nursery (URRN). For ARPT, replicated plots will be planted in at least 6 locations across Arkansas. Plots will be 20 feet long with 8 rows of rice at an 8 inch row spacing. Rice lines and check varieties will be grouped into one of four maturity groups, with 26 entries per group and 3 replications. The URRN strains will be planted at one location, with similar plot dimensions and replications as the ARPT, for a total of 200 entries. AAES will pass de-hulled samples of the rice from the varieties through a color-sorter, followed by manual evaluation of discoloration by stink bugs or other causes. Data will help in the decision whether to release a variety, and will inform growers of variety susceptibility to stink bugs. Objective 3. To develop strategies to maintain the effectiveness of current pest-control techniques. Mosquito control agencies are very concerned about preventing insecticide resistance, because few chemical compounds are registered for mosquito abatement. Two collaborative projects address this issue. TAES is engaged in a long-term project to establish resistance monitoring and prevention. TAES discovered elevated tolerance to pyrethroids in Harris County, and to malathion in Jefferson Co, raising the question of whether resistance is arising across the region. TAES and CAES will quantify mosquito resistance to 6 commonly-used insecticides using Culex quinquefasciatus, a broadly distributed vector of West Nile Virus. Eggs will be collected from various locations using hay-infusion gravid traps, with samples being contributed by TAES, LAES, CAES, and MAES. Recently emerged adults will be tested for resistance using a modified bioassay (Plapp, 1971). Mosquitoes will be exposed to standardized concentrations of insecticide in scintillation vials (30 females per concentration, 5 per vial), with control vials containing only the diluent. TAES and/or CAES will compare 24 h mortalities of wild-collected populations to a susceptible laboratory strain using Probit analysis with Abbott's C correction for mortality in controls. Any positive results and patterns of cross-resistance will be used to develop a resistance management program that will be transferred to vector control districts. B.t.i. is an important bacterial insecticide that is safe for most non-target insects. Its heavy use raises concerns about resistance management. CAES-Riverside will use selection and genetic analyses to determine how mosquitoes inherit resistance to B.t.i.. CAES-R has developed 4 colonies of Cx. quinquefaciatus that are resistant to various combinations of 3 Cry toxins (the active components of B.t.i.). We will use cross-breeding experiments and Mendelian analysis to discover the pattern of inheritance of resistance to Cry toxins. Reciprocal mass crosses between each resistant colony and a susceptible colony will use >200 virgins from each colony. F1 offspring will be bioassayed to determine dominance, sex linkage, maternal effects and cross resistance to other Cry toxins. Backcrosses will help us estimate the number of loci involved. Laboratory assays will be reinforced by in vivo toxin binding assays, which will show whether the toxin(s) are active in mosquito midguts. LAES, MAES and TAES will send samples of Cx. quinquefaciatus to CAES-Riverside for resistance testing to quantify efficacy of B.t.i. across the southern region. Objective 1 Station:AAES, CAES, LAES Objective 2 Station: AAES, CAES, KAES, LAES, MAES, TAES Objective 3 Station: LAES, CAES, AAES, TAES Table 1. Project participation according to objective

Measurement of Progress and Results

Outputs

• Information outputs. We plan to produce at least 15 new sets of information or data that will be of great importance to stakeholders. These will be disseminated as printed scientific materials, including peer-reviewed papers in scientific journals, technical reports, and abstracts from scientific meeting presentations. Where possible, the outputs will also be included in extension materials such as Cooperative Extension (CE) publications or updates, grower handouts, and online publications.
• Our work on pest biology and ecology (Objective 1) will have the following outputs produced as flyers, online information and updates to CE publications (e.g. AAES Rice Production Handbook, UC IPM Rice Pest Management Guidelines): 1. Recommendations for planting dates that minimize pest problems in various areas of the region. 2. A protocol for identifying fields at risk for stink bug. 3. A protocol for identifying fields at risk for armyworm. 4. Development of a cultural control method for armyworms (i.e. targeted weed control). 5. Improved designs for water treatment wetlands that reduce mosquito problems (publications are planned for the journal Wetlands and for CE outlets). New CE publications will be produced on rice stink bug, grape colaspis and armyworms, as needed.
• The integrated research program on pest control (Objective 2) will have the following outputs to be disseminated as grower handouts, technical reports or new CE publications: 6. Datasets that will show which insecticides are effective against pests, while simultaneously alerting growers and vector control personnel to materials that may disrupt natural biological control. 7. Establishment of an economic treatment threshold for Mexican rice stem borer. 8. Establishment of economic treatment threshold for armyworms. 8. Identification of insecticides that are effective against grape colaspis. 9. A protocol for perimeter treatments to protect human habitation from mosquitoes. 10. Optimized ULV spray treatment methods. 11. An evaluation of the safety of ULV sprays for aquatic invertebrates. 12. Rankings of rice cultivars for yield and susceptibility to pest problems
• The research program on maintaining the efficacy of pest control (Objective 3) will produce the following: 13. A West Nile Virus surveillance program for several counties in Texas. 14. An insecticide resistance management program for chemical control of mosquitoes. 15. A data set that will be crucial for developing a resistance management program for the use of bacterial larvicides against larval mosquitoes. These outputs will be made available to growers and vector abatement districts in a variety of formats (online, workshops, in industry publications targeted to growers, as part of the scientific publications mentioned above, meetings and field days).

Outcomes or Projected Impacts

• We expect our project to have numerous positive impacts on rice agriculture and vector control. Main categories of benefits are underlined below, at the first mention for each. For Objective 1 (pest biology), better understanding of the ecology of rice pests will allow growers to detect and head off pest problems before they experience crop losses, thus the impact will be cost-savings for growers and higher yields. Cultural control methods will minimize the need for insecticide applications, thus reducing costs, environmental contaminants and the risk of secondary pest outbreaks. Improved wetland designs that reduce mosquito populations will reduce disease risks and annoyance problems.
• For Objective 2 (integrated pest management), we will inform growers of the outcomes of treatments, so that they can choose effective materials and application methods that are less likely to interfere with natural mosquito control, or to cause secondary pest outbreaks. This has several impacts: a reduced need for vector control, reduced vector-borne disease risks, and a reduced need to control secondary pests. Identification of pest-resistant cultivars will allow growers to minimize the application of chemical insecticides. This yields cost savings, protects beneficial species and reduces insecticide applications to this sensitive aquatic agroecosystem. Similarly, establishment of economic treatment thresholds will yield cost-savings and decrease unnecessary insecticide use. Research on Wolbachia in mosquitoes has the potential to suppress mosquito populations without the use of chemicals. Development of an effective protocol for perimeter treatments against mosquitoes will decrease disease risks, and this method could help protect deployed troops in areas that lack vector control. Optimizing ULV sprays and risk assessment for ULV will lead to lower environmental contamination, lower disease risks, and more informed communications between vector control districts and wetlands managers.
• The insecticide resistance studies established under Objective 3 will help preserve the efficacy of chemical and bacterial materials used to control mosquitoes. Because few materials are registered for mosquito control, effective resistance management is key for the future protection of public health. Rural residents and livestock near irrigated wetlands are especially at risk. Mosquito problems can also decrease property values and discourage farmworkers from seeking employment in affected areas.

Milestones

(0):t of our methods are of proven efficacy, thus we anticipate few milestones in the sense that completion of our objectives is contingent upon developing new techniques. However, two projects will require either ground-truthing of methods or development of mosquito strains before the main objectives can be accomplished. Work on the efficacy of perimeter sprays of residual insecticides will require small-plot tests before further work is justified. A successful local reduction of mosquitoes via perimeter spray will be a significant milestone. Our work on the biology of B.t.i. toxin resistance requires successful crosses and backcrosses among four resistant strains of mosquitoes and a susceptible strain. The production of F1 offspring and of backcrosses will be significant milestones.

Projected Participation

View Appendix E: Participation

Outreach Plan

We plan extensive outreach activities to disseminate the results of our research to academics and stakeholders in both the government and private sectors. Our primary academic outreach goal is to produce peer-reviewed papers for scientific journals. Nearly all of our papers cited above are in peer-reviewed scientific journals, which are the 'gold standard' for quality in scientific writing. We will also continue to present research results at national scientific meetings, to societies that are either primarily academic (e.g., Entomological Society of America, Ecological Society of America, American Association of Tropical Medicine and Hygiene, Society for Vector Ecology), or a mixture of academic and industry scientists and professionals (e.g. American Mosquito Control Association, Rice Technical Working Group).

While presentations to other scientists are crucial to advancing research on pest biology and control, it is also very important to us to see our advances applied. We are committed to outreach efforts to communicate the results of our work to stakeholders such as growers, farm advisors, mosquito and vector control districts, wildlife managers, members of the pest control industry, seed producers and other interested parties, including members of the general public. All of our scientists contribute extensively to outlets that reach the aforementioned stakeholders, such as technical bulletins (some of which are also peer-reviewed), agricultural magazines, online resources and the popular press. Space does not permit us to list all of these publications here; the reader is referred to the S-300 website for both peer-reviewed and technical publications: http://www.lgu.umd.edu/lgu_v2/homepages/pub.cfm?trackID=1258#4. Representative outreach publications include Rice Production Guidelines, annual reports to rice growers for the member states, field day reports, and a large number of online resources for rice growers and/or for mosquito control in agriculture (e.g. numerous University of California Pest Management Guidelines by L. D. Godfrey: http://www.ipm.ucdavis.edu/PMG/selectnewpest.rice.html, 'Mosquitoes in Agriculture' by Lawler and Lanzaro 2005, http://anrcatalog.ucdavis.edu/pdf/8158.pdf,). Stakeholders greatly appreciate our efforts. For example Dr. M.O. Way received the 2004 Rice Industry Award for his research and extension work in rice.

In addition to online and paper publications, we will continue to use 'in person' outreach methods. Growers, mosquito abatement personnel, wildlife managers and the public are more likely to utilize research findings when they are able to interact with scientists. Interactive settings allow stakeholders to gain clarifications and information as to whether techniques are appropriate to their circumstances. Whether or not they have extension appointments, our members regularly give presentations at grower group meetings, field days, regional and state mosquito and vector control meetings, water resources meetings, and at continuing education classes, which are required for pesticide applicators. These activities will continue. Project participants will present research talks at the annual meetings of the Rice Technical Working Group, the meetings of State and National Mosquito Control Associations (e.g. American Mosquito Control Association, CA and TX mosquito control associations), rice field days sponsored by cooperative extension, and grower group meetings. In addition to grower and commodities groups, our participants are often invited to join workshops or to participate in meetings with other stakeholders from rice growing areas. During the S-300 project scientists were asked to share their expertise with duck club owners, an air quality board (regarding straw management practices), public health agencies and wildlife managers. We will continue these activities as requested.

Organization/Governance

The organizational framework of scientists involved in this project will follow the guidelines of the Manual for Cooperative Regional Research. Research and other activities will be planned and coordinated by the Multi-State Project Technical Committee. This committee will be comprised of all State Agricultural Experiment Station (SAES) scientists who will perform the research described herein. There will be one voting member per state. This group will form the Executive Committee for the project and its administration. This committee will also include two non-voting CSREES advisors: a Regional Administrative Advisor and a non-voting Administrative Consultant representing CSREES - Washington, D.C.. Offices to be held on the Executive Committee and the project are Chair and Recording Secretary. These officers will be nominated and elected by voting SAES members. The term of office is one year.

The Chair of the Technical Committee, in consultation with the CSREES advisors, will notify the Technical Committee of pending meeting dates, times and locations. The Chair will preside over all meetings of the Committee. The Chair will prepare, or supervise the preparation of, the Project's Annual Report for the year during which he or she held office. The Recording Secretary will record the minutes of any meetings held by the Technical Committee or Executive Committee. He or she will assist the Chair in setting up meetings, as needed, and will preside over any meetings that the Chair is unable to attend. Other duties may be assigned to either the Chair or Recording Secretary by the CSREES Administrative Advisor, the Executive Committee, or the Technical Committee as a whole.

The Technical Committee will meet at least once during the early spring of each project year, well in advance of the due date for the Annual Regional Project Report. The purpose of the meeting will be to review research progress, report results, and to plan research and other project activities for the coming year. New officers will be nominated and elected at this meeting. Additional meetings may be held by the Executive Committee or Technical Committee as needed or called for by members of this committee, its officers, or its CSREES Administrative Advisor.

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Attachments

Land Grant Participating States/Institutions

AR, CA, LA, MO, MS, TX

Non Land Grant Participating States/Institutions