Progress 08/01/02 to 06/06/05
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? This project is scheduled to end on August 31, 2005, and a new project beginning September 1, 2005 has been approved to succeed it. Lowering the economic and environmental costs of traditional insecticide applications is the major issue being addressed by the project. Major emphasis is on the potential for using entomopathogenic fungi and sterile tarnished plant bugs(TPB) for controlling the pest while it resides on the alternate hosts on which it multiplies prior to invading cotton fields. Finding highly virulent isolates that have a low impact on beneficial insects and formulating these isolates to improve survival of the fungi in the environment is especially important to the project. Additional research is on TPB attraction, diapause, designing an efficient TPB trap, and investigating the potential
of augmenting natural epizootics of the cotton aphid fungus. How serious is the problem? Cotton yield losses to tarnished plant bugs (TPB) and their western cousins are second only to the bollworm/budworm complex. Percentage of yield lost to plant bugs has been near 1% since 1990. Why does it matter? In 2004, the latest reporting year, insecticide was applied to 4.2 million acres, and yield loss plus cost of control totaled approached $200 million. The economic and environmental costs of traditional control of plant bugs are significant, and may be reduced by the technology being studied by project scientists. 2. List the milestones (indicators of progress) from your Project Plan. A. Management of L. lineolaris and stink bugs on wild hosts. 12 months: Select isolates for further evaluation from bioassays and UV testing. Select oil, oil-emulsion, and water carriers from bioassays and UV testing. Evaluate 5 major formulation strategies from bioassays and UV testing. Search for new
indigenous isolates. 24 months: Bioassay of select isolates against beneficial insects. Further evaluation of select formulation strategies. Small-scale field trials using caged-insects on a few select isolate-formulation combinations. Continued search for new indigenous isolates. 30 months: Scale-up production of select isolates using bag fermentation. Expand small scale field trials to application over a wide area without caged insects for a few select isolate-formulation combinations. B. Augmentation of Natural Epizootics of N. fresenii in A. gossypii. 12 months: First year field experiment on jump-starting N. fresenii epizootics with infective greenhouse populations. 24 months: Second year field experiment on jump-starting N. fresenii epizootics with infective greenhouse populations. C. Sterility of irradiated bugs. 12 months: Confirm disease-free colony. Determine optimum dosage for parental and F1 sterility. 24 months: Confirm optimum dosage for parental and F1
sterility and determine mortality and competitiveness in lab. 30 months: Release into field cages for competitiveness and efficacy studies. D. Attraction and response. 12 months: Construct and develop olfactometers and field traps. Begin measurements of attraction and response of treated and untreated bugs. Screen attractant extracts and chemicals. 24 months: Determine best olfactometers and field traps. Continue measurements of attractiveness and responsiveness of treated and untreated bugs. Screen attractant extracts and chemicals. 30 months: Continue improving olfactometers and traps and continue tests of attraction and response of treated bugs. Take candidate extracts and chemicals to field for evaluation. E. Diapause. 12 months: Develop methods to allow maximum TPB survival in environmenal chambers. Determine incidence of diapause at simulated times of year. 24 months: Determine which nymphal stages are most susceptible to diapause inducing stimuli, and conditions
that terminate diapause and reproductive activity of bugs. 30 months: Develop methods to hold bugs for measuring rates of respiration of treated and untreated bugs. 3a List the milestones that were scheduled to be addressed in FY 2005. For each milestone, indicate the status: fully met, substantially met, or not met. If not met, why. 1. Management of TPB on wild hosts with entomopathogenic fungi. Milestone Substantially Met 2. Augmentation of natural epizootics of the cotton aphid fungus. Milestone Substantially Met 3. Sterility of irradiated bugs. Milestone Substantially Met 4. Attraction and response. Milestone Substantially Met 5. Diapause. Milestone Not Met Progress slowed by resource limitation (human,fiscal,equipment, etc. 3b List the milestones that you expect to address over the next 3 years (FY 2006, 2007, and 2008). What do you expect to accomplish, year by year, over the next 3 years under each milestone? Note: This project is scheduled to end on August 31, 2005, and a
new project beginning September 1, 2005 has been approved to succeed it. The following milestones were taken from the new project. Management of TPB and on wild hosts with entomopathogenic fungi. 1) Scaled-up production of fungal formulations. 2) Small scale field trials of formulated fungal isolates against L. lineolaris in wild host plants. 3) Small scale field trials of formulated fungal isolates against L. lineolaris in cotton. 4) Additional scale-up of fungal isolate production at the National Biological Control Laboratory. 5) Evaluation of a select fungal isolate against L. lineolaris in a range of the most significant wild host plants in during the spring, summer, and fall. 6) Incorporation of scaled-up formulation of fungi into wild host plant trials. 7) Large scale field trials of select isolates against L. lineolaris in cotton and against L. hesperus in alfalfa (CA collaboration). 8) Initial incorporation of new isolate into TPB area-wide management program
currently targeting management of wild host plants with herbicides and mechanical destruction. Augmentation of natural epizootics of N. fresenii in A. gossypii. 1) Second year study to determine if N. fresenii epizootics may be initiated through inoculation in small-scale (1 acre) plots. 2) Evaluate the rate of spread of initiated N. fresenii epizootics across large acreages. 3) Develop improved methods for collecting and preserving N. fresenii infected aphids from cotton fields during peak epizootics. 4) Improve methods for collecting, storing, and disseminating inocula to initiate epizootics. Enhance area-wide management of TPB with sterile insect technique. 1) Lab tests developed. 2) Determine competitiveness of sterile TPB in the lab. 3) Determine competitiveness of sterile TPB in the field. 4a What was the single most significant accomplishment this past year? Flight, mating, attractiveness, and responsiveness of irradiated TPB was studied and found to equal or approach
that of unirradiated bugs. 4b List other significant accomplishments, if any. 1) Initiated scaled-up production for three selected B. bassiana from Lygus spp. isolates and established related facilities at the NBCL. 2) Field trials were conducted with in MS, comparing three B. bassiana isolates against L. lineolaris and application rates for one select ARS isolate. Collaborators conducted field trials with a select ARS B. bassiana isolate produced at the NBCL against L. lineolaris in cotton (AR) and L. hesperus in alfalfa (WA). Additional work was done by collaborators in CA, to evaluated movement of infected L. hesperus from alfalfa into cotton following treatment with B. bassiana in 2005. 3) Inoculative releases of N. fresenii infected aphids to initiate epizootics were made in 2004 and resulting epizootiology studied. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Significant milestones achieved over the 30-month
life of the current project follow: Sterile TPB research established optimum dosages of radiation required to produce sterility in treated parents and F1 progeny; relative flight propensity, mating propensity, attractiveness, and responsiveness of irradiated to unirradiated TPB; design, construction, and subsequent improvement of an effective non-sticky field trap; and establishing a model of seasonal diapause in TPB. Natural B. bassiana infection levels in TPB populations of MS, were determined and published. Isolates from this survey and a related survey in CA, were screened for pathogenicity to two Lygus spp. and eight non- target species, in vitro spore production, mycotoxins, temperature growth optima, and UV tolerance. The genetic relatedness of 4 isolates from MS, 3 isolates from CA, and GHA was determined. Initial scale-up production for select isolates was conducted in 2004 at USDA-ARS, Sydney, MT, followed by USDA-ARS, NBCL, Stoneville, MS, in 2005. Field trials targeting
Lygus spp. were conducted in MS and CA in 2004 for one isolate each from MS and CA and a commercial B. bassiana isolate (GHA). Field trials were conducted in MS in 2005 comparing isolates and application rates and in CA, AR and WA through collaborators. These field trials indicate potential for high infection rates in Lygus spp. and very low infection rates in non-target beneficial insects. A formulation was developed that provides significant protection of spores from artificial sunlight. Results from field persistence studies in 2004-2005 indicate a need for improving spore survival in the field and field trials with formulated spores are planned for 2005-2006. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? No science or technology transferred
yet. Commercial interest in entomopathogenic fungi for Lygus control will first require demonstration of successful field trials. Field efficacy may be improved by selection of highly pathogenic isolates and improvements in persistence through formulation. Isolates have been selected that are highly pathogenic and formulations that significantly improve UV tolerance. Other technical factors critical to commercial development, such as in vitro production capacity and mycotoxin production, have been investigated and results are favorable. Market factors, including the size and penetration of the market, will need to be considered. Regarding potential market size, Lygus is a significant pest of many high value crops. Control of Lygus and other susceptible insect pests in a range of crops will need to be investigated through collaborations to expand market size. Regarding potential market penetration, entomopathogenic fungi could fill niches not currently targeted with chemical
insecticides (e.g. populations in wild host plants) , and a relatively narrow spectrum of insecticide chemistry is currently available for Lygus control, which may be threatened by regulatory actions (e.g. FQPA) and resistance development. Information on the economic impact of area-wide management of TPB in wild host plants through wild host plant destruction is currently being gathered in another project. This information may help to justify the investment control strategies targeting populations in wild host plants. Ultimately the projected returns based on market size and penetration will need to justify registration costs and investment. Some data currently being collected in the development of the isolates could potentially be referred to in the registration package differing some of the registration costs. Commercial development of the cotton aphid fungus would not follow the typical microbial biopesticide development paradigm as long as it cannot be produced in vitro. However,
epizootics of this fungus have tremendous potential to spread once initiated. Therefore, relatively little investment in inoculation could have large returns in control. Potentially, grower cooperative groups or small companies could provide sufficient infrastructure for the collection, storage, and inoculation of fields with N. fresenii infected cadavers. A model for grower cooperative investment in the cotton aphid fungus is currently in place through the Cotton Aphid Fungus Sampling Service funded by Cotton Incorporated. This program has provided very significant returns to the growers from saved aphicide applications. We are still in the proof-of-concept phase of this project, demonstrating that epizootics may be initiated prior to natural epizootics and, if so, how early and under what conditions. If these results are promising we will investigate the rate of spread of initiated epizootics and improve efficiencies of collection, storage, and inoculation. Futher investigation will
need to be done to determine if such an approach to control would be exempt from registration requirements, a major hurdle to small startup companies, since the fungus is highly specific and is naturally prevalent over a wide geographic area.
Impacts
(N/A)
Publications
- Leland, J.E., Mullins, D.E., Vaughan, L.J., Warren, H.L. 2005. Effects of media composition on metarhizium anisopliae var. acridum spores, part 2: effects of media osmolality on cell wall characteristics, carbohydrate concentrations, drying stability, and pathogenicity.. Biocontrol Science and Technology.
- Leland, J.E., Mcguire, M.R., Jaronski, S. 2005. Field evaluation of beauveria bassiana isolates for control of plant bug (lygus spp.). National Cotton Council Beltwide Cotton Conference.
- Villavaso, E.J., Snodgrass, G.L. 2005. Diapause in tarnished plant bug, lygus lineolaris (heteroptera: miridae): seasonal occurrence in a mississippi population. Journal of Agricultural and Urban Entomology.
- Villavaso, E.J. 2005. Effects of irradiation on reproduction in tarnished plant bug, lygus lineolaris (heteroptera: miridae) and f1 progeny.. Journal of Entomological Science.
- Leland, J.E., Behle, R.W. 2005. COATING BEAUVERIA BASSIANA WITH LIGNIN FOR PROTECTION FOR SOLAR RADIATION AND EFFECT ON PATHOGENICITY TO LYGUS LINEOLARIS. Biocontrol Science and Technology.
- Leland, J.E., Mullins, D.E., Vaughan, L.J., Warren, H.L. 2005. Effects of media composition on metarhizium anisopliae var. acridum spores, part 1: comparison of cell wall characteristics and drying stability among three spore types. Biocontrol Science and Technology.
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Progress 10/01/03 to 09/30/04
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? Cotton yield losses to tarnished plant bugs (TPB) and their western cousins are second only to the bollworm/budworm complex. Percent of yield lost to plant bugs has been reasonably consistent since 1990. In 2003, the latest reporting year, insecticide was applied to 3.7 million acres, and yield loss plus cost of control totaled over $100 million. Lowering the economic and environmental costs of traditional insecticide applications is the major issue being addressed by the project. Major emphasis is on the potential for using entomopathogenic fungi and sterile TPB for controlling the pest while it resides on the alternate hosts on which it multiplies prior to invading cotton fields. Finding highly virulent isolates that have a low impact on beneficial insects and formulating these isolates to
improve survival of the fungi in the environment is especially important to the project. Additional research is on TPB attraction, diapause, designing an efficient TPB trap, and investigating the potential of augmenting natural epizootics of the cotton aphid fungus. 2. List the milestones (indicators of progress) from your Project Plan. Entomopathogenic Fungi for Controlling TPB 1) Discovery of new entomopathogenic fungi isolates from L. lineolaris. 2) Evaluation of fungal isolates from L. lineolaris and L. hesperus for characteristics relevant to mycoinsecticide development (i.e. pathogenicity to target and beneficial insects, in vitro production, temperature optima, mycotoxin production, and UV tolerance). 3) Scale-up production of select fungal isolates. 4) Small-scale field trials with select isolates against L. lineolaris in wild host plants. 5) Small-scale field trials with select isolates against L. lineolaris in cotton. 6) Small-scale field trials with select isolates
against L. hesperus in alfalfa (CA collaboration). 7) Laboratory evaluation of formulations for protecting fungal isolates from solar radiation. 8) Scaled-up production of fungal formulations. 9) Small scale field trials of formulated fungal isolates against L. lineolaris in wild host plants. 10) Small scale field trials of formulated fungal isolates against L. lineolaris in cotton. 11) Additional scale-up of fungal isolate production at the National Biological Control Laboratory. 12) Evaluation of a select fungal isolate against L. lineolaris in a range of the most significant wild host plants in during the spring, summer, and fall. 13) Incorporation of scaled up formulation of fungi into wild host plant trials. 14) Large scale field trials of select isolates against L. lineolaris in cotton and against L. hesperus in alfalfa (CA collaboration). 15) Incorporation of new isolate into TPB area-wide management program currently targeting management of wild host plants with
herbicides and mechanical destruction. Augmenting Cotton Aphid Fungus Epizootics 1) Investigate the interaction of N. fresenii epizootics with cotton planting date and corresponding variables (i.e. aphid population densities, relative humidity, temperature, and light penetration). 2) Determine if N. fresenii epizootics may be initiated through inoculation in small-scale (1 acre) plots. 3) Determine if there is an interaction between epizootic initiation through inoculation and cotton planting date. 4) Evaluate the rate of spread of initiated N. fresenii epizootics across large acreages. 5) Develop improved methods for collecting and preserving inocula from cotton field during peak N. fresenii epizootics. 6) Develop improved methods for disseminating inocula to initiate epizootics. Sterility of irradiated bugs. Attraction and response. Diapause. 3. Milestones: Management of TPB on wild hosts with entomopathogenic fungi. 1) A survey of natural B. bassiana infection in TPB
populations of the MS delta and hill country was completed. 2) Two isolates were selected from a pool of isolates from L. hesperus and L. lineolaris for further development based on pathogencicity to target and beneficial insects, in vitro production, temperature optima, mycotoxin production, and UV tolerance. 3) Laboratory evaluations of formulations for protecting B. bassiana spores from solar radiation were completed. 4) Molecular markers were developed for select B. bassiana isolates. 5) Scaled-up production was conducted for two selected B. bassiana isolates each from the L. hesperus and L. lineolaris isolate collections, which was ahead of schedule. 6) Small scale field trials were conducted against TPB on wild host plants using one isolate from L. hesperus, one from L. lineolaris, and a commercial isolate. Sister studies were conducted using the same isolates against L. hesperus on alfalfa in California. These studies also provided information on field pathogenicity to
select beneficial insects. This was ahead of schedule. 7) Small scale field trials were conducted against TPB in cotton using an isolate from L. lineolaris and a commercial isolate. These studies also provided information on contribution of direct spray versus uptake from contaminated surface to pathogenicity, field persistence of spores, and effects on beneficial insects. This was ahead of schedule. Augmentation of natural epizootics of the cotton aphid fungus. 1) A second year experiment was conducted investigating the interaction of cotton aphid fungus epizootiology and cotton planting date. 2) A first year experiment was conducted to evaluate the potential for initiating cotton aphid fungus epizootics using inocula and additional inocula was collected and stored for further experimentation in subsequent years. This was ahead of schedule. Sterility of irradiated bugs. Confirm disease-free colony: Disease-free colony was established and is currently being maintained for
research. Determine optimum dosage for parental and F1 sterility: Optimum dosages between 10 and 20 krad were established. Attraction and response. Construct and develop olfactometers and field traps: An effective, non- sticky trap was developed, tested, and found to be superior to existing sticky traps. Non-sticky traps are much more user-friendly than sticky traps. A newly developed olfactometer has produced positive, but less than desirable results. Work continues on developing a better one. Begin measurements of attraction and response of treated and untreated bugs: Efforts to determine the attractiveness of treated versus untreated females and responsiveness of treated versus untreated males have been unsuccessful thus far because of lack of response. Efforts will continue. Screen attractant extracts and chemicals: No extracts or chemicals have been tested. Diapause. Develop methods to allow maximum TPB survival in environmental chambers: A new method of using a natural
food (corn) and humidity control in environmental cabinets has resulted in high survival of test insects and consistently successful diapause research. Determine incidence of diapause at simulated times of the year: Incidence of diapause has been determined for every month of the year in environmental cabinets programmed to simulate natural cycles of increasing or decreasing day length. Both a sunrise to sunset and a civil twilight models were tested, and the civil twilight model closely matched field observations, thus confirming the validity of the environmental cabinets as means to study diapause. B. Milestones expected to be addressed over the next 3 years: (Note: Project plan for 2005 through 2010 is currently in review) Management of TPB and on wild hosts with entomopathogenic fungi. 1) Scaled-up production of fungal formulations. 2) Small scale field trials of formulated fungal isolates against L. lineolaris in wild host plants. 3) Small scale field trials of formulated
fungal isolates against L. lineolaris in cotton. 4) Additional scale-up of fungal isolate production at the National Biological Control Laboratory. 5) Evaluation of a select fungal isolate against L. lineolaris in a range of the most significant wild host plants in during the spring, summer, and fall. 6) Incorporation of scaled-up formulation of fungi into wild host plant trials. 7) Large scale field trials of select isolates against L. lineolaris in cotton and against L. hesperus in alfalfa (CA collaboration). 8) Initial incorporation of new isolate into TPB area-wide management program currently targeting management of wild host plants with herbicides and mechanical destruction. Augmentation of natural epizootics of N. fresenii in A. gossypii. 1) Second year study to determine if N. fresenii epizootics may be initiated through inoculation in small-scale (1 acre) plots. 2) Second year study to determine if there is an interaction between epizootic initiation through
inoculation and cotton planting date. 3) Evaluate the rate of spread of initiated N. fresenii epizootics across large acreages. 4) Develop improved methods for collecting and preserving N. fresenii infected aphids from cotton fields during peak epizootics. 5) Improve methods for collecting, storing, and disseminating inocula to initiate epizootics. Sterility of irradiated bugs. Confirm optimum dosage for parental and F1 sterility and determining mortality and competitiveness in lab. Release into field cages for competitiveness and efficacy studies. Attraction and response. Determine best olfactometers and field traps. Continue measurements of attractiveness and responsiveness of treated and untreated bugs. Screen attractant extracts and chemicals. Continue improving olfactometers and traps and continue tests of attraction and response of treated bugs. Take candidate extracts and chemicals to field for evaluation. Diapause. Determine which stages are most susceptible to diapause
inducing stimuli, and conditions that terminate diapause and reproductive activity of bugs. Develop methods to hold bugs for measuring rates of respiration of treated and untreated bugs. 4. What were the most significant accomplishments this past year? A. Single most significant accomplishment during FY 2004 (One per Research (00D) Project): The incidence of diapause for TPB eggs hatching in all months of the year has been modeled in environmental cabinets. Fall diapause predictions in the cabinets closely follow those reported in field observations indicating the utility of environmental cabinets for diapause studies in TPB. B. Other significant accomplishments, if any: 1) Scaled-up production for four selected B. bassiana from Lygus spp. isolates. 2) Small scale field trials were conducted against L. lineolaris on wild host plants and cotton and against L. hesperus in alfalfa though collaborators in CA using products from scaled-up production. 3) Inoculative releases of N.
fresenii infected aphids to initiate epizootics were made and resulting epizootiology studied. C. Significant activities that support special target populations: None. D. Progress Report None 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Project is beginning second year and the invention of an effective non- sticky trap is the major accomplishment of the project to date. New isolates of B. bassiana were discovered from L. lineolaris and a few select isolates that demonstrated promising characteristics were evaluated in small scale field trials against L. lineolaris and L. hesperus. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? No science or technology transferred yet. Commercial
interest in entomopathogenic fungi for Lygus control will first require demonstration of successful field trials. Field efficacy may be improved by selection of highly pathogenic isolates and improvements in persistence through formulation. Isolates have been selected that are highly pathogenic and formulations that significantly improve UV tolerance. Other technical factors critical to commercial development, such as in vitro production capacity and mycotoxin production, have been investigated and results are favorable. Market factors, including the size and penetration of the market, will need to be considered. Regarding potential market size, Lygus is a significant pest of many high value crops. Control of Lygus and other susceptible insect pests in a range of crops will need to be investigated through collaborations to expand market size. Regarding potential market penetration, entomopathogenic fungi could fill niches not currently targeted with chemical insecticides (e.g.
populations in wild host plants) , and a relatively narrow spectrum of insecticide chemistry is currently available for Lygus control, which may be threatened by regulatory actions (e.g. FQPA) and resistance development. Information on the economic impact of area-wide management of TPB in wild host plants through wild host plant destruction is currently being gathered in another project. This information may help to justify the investment control strategies targeting populations in wild host plants. Ultimately the projected returns based on market size and penetration will need to justify registration costs and investment. Some data currently being collected in the development of the isolates could potentially be referred to in the registration package differing some of the registration costs. Commercial development of the cotton aphid fungus would not follow the typical microbial biopesticide development paradigm as long as it cannot be produced in vitro. However, epizootics of
this fungus have tremendous potential to spread once initiated. Therefore, relatively little investment in inoculation could have large returns in control. Potentially, grower cooperative groups or small companies could provide sufficient infrastructure for the collection, storage, and inoculation of fields with N. fresenii infected cadavers. A model for grower cooperative investment in the cotton aphid fungus is currently in place through the Cotton Aphid Fungus Sampling Service run by Don Stienkraus (U or AR) funded by Cotton Incorporated. This program has provided very significant returns to the growers from saved aphicide applications. We are still in the proof-of-concept phase of this project, demonstrating that epizootics may be initiated prior to natural epizootics and, if so, how early and under what conditions. If these results are promising we will investigate the rate of spread of initiated epizootics and improve efficiencies of collection, storage, and inoculation.
Futher investigation will need to be done to determine if such an approach to control would be exempt from registration requirements, a major hurdle to small startup companies, since the fungus is highly specific and is naturally prevalent over a wide geographic area.
Impacts
(N/A)
Publications
- Leland, J.E., Mcguire, M.R. 2004. Strain selection of a fungal entomopathogen, beauveria bassiana, for control of plant bugs (lygus spp.). National Cotton Council Beltwide Cotton Conference.
- Leland, J.E., Behle, R.W. 2004. Formulation of the entomopathogenic fungus, beauveria bassiana, with resistance to uv degradation for control of tarnished plant bug, lygus lineolaris. National Cotton Council Beltwide Cotton Conference.
- Leland, J.E., Hardee, D.D. 2004. Cotton planting date and epizootiology of the cotton aphid fungus, neozygites fresenii. National Cotton Council Beltwide Cotton Conference.
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Progress 10/01/02 to 09/30/03
Outputs
1. What major problem or issue is being resolved and how are you resolving it? Awareness of the economic impact of the tarnished plant bug, Lygus lineolaris, has increased as boll weevil eradication progressed westward across the cotton producing states of the south. Our current focus is on the biology of TPB with major emphasis on the potential for using sterile TPB and entomopathogenic fungi for controlling the pest while it resides on the alternate hosts on which it multiplies prior to invading cotton fields. Finding highly virulent isolates that have a low impact on beneficial insects and formulating these isolates to improve survival of the fungi in the environment is especially important to the project. Additional research is on TPB attraction and diapause and investigating the potential of augmenting natural epizootics of the cotton aphid fungus, Neozygites fresenii, in order to speed-up the onset and increase the magnitude of epizootics. Reducing application
of traditional pesticides is a major goal. 2. How serious is the problem? Why does it matter? Multiple applications of insecticide to control the boll weevil and lepidopterous pests often masked or overwhelmed the importance of TPB. With the steady progress of boll weevil eradication westward and the wide- scale use of transgenic cotton, insecticide application to cotton fields has been minimized and the economic impact of TPB has become easier to discern. Insecticides are currently used to control TPB, but the bug has demonstrated a proclivity for developing resistance to them. The release of sterile plant bugs and applications of entomopathogenic fungi are non- insecticidal means of control, and evaluating their potential for economic use are major foci of our research. Implementation of a sterile release program and/or area-wide control with entomopathogenic fungi in lieu of insecticide applications would give natural enemies of TPB and other cotton pests the opportunity to
mollify pest damage thereby providing significant environmental savings. Although naturally occurring epizootics of N. fresenii are able to control cotton aphid populations once established, aphicide applications are often made prior to the establishment of the epizootics. Options for controlling cotton aphids are limited by the potential of this pest to rapidly develop high levels of resistance to chemical insecticides. Augmenting natural epizootics of N. fresenii may reduce the need for controlling cotton aphid populations with chemical insecticides by speeding the onset and increasing the severity of epizootics. 3. How does it relate to the National Program(s) and National Program Component(s) to which it has been assigned? Our research is centered on determining if sterilization and release of mass-reared TPB and applications of entomopathogenic fungi can be used to control natural populations of this bug. TPB appears to be a particularly good candidate for this method of control
because progeny of partially sterile bugs are also sterile, and two generations (or more) of sterile bugs will result from a single release. Sterile insect releases also result in less insecticide being applied to the environment. The project contributes to the Natiional Program Crop Protection and Quarantine.(304). 4. What were the most significant accomplishments this past year? A. Single Most Significant Accomplishment: Current traps for TPB have all involved the use of a user-unfriendly sticky material and the use of live female bugs. This combination has resulted in very limited use of TPB traps to monitor or suppress populations. We have recently invented a TPB trap that does not require sticky material, and an invention report is in preparation. When TPB pheromone is identified and synthesized (a virtual certainty within the next few years), the trap/pheromone combination should see widespread usage in cotton and other commodities in which TPB causes economic damage. B. Other
Significant Accomplishments: The dosage of irradiation required for a high degree of parental sterility and complete F1 sterility was determined to be15 krad. Parental sterility of 99.7% or more was achieved by treating parents with 20 krad. Several isolates of entomopathogenic fungi were shown to be highly virulent to TPB and western TPB (WTPB). New isolates were obtained from field collected TPB and from WTPB through collaboration with Michael McGuire (USDA-ARS, Shafter, CA). Select isolates from TPB and WTPB were shown to be as much as 10 to 100x more virulent to TPB and WTPB than commercial isolates currently available for Lygus spp. control. New isolates from TPB and WTPB were shown to be able to grow at higher temperatures typical of field conditions, outside the temperature growth range of the commercial isolate. A 20 county survey was conducted in the late spring through the summer of 2003 to evaluate natural incidence entomopathogenic fungi infection in TPB populations. This
survey is continuing through the fall of 2003 on a more limited geographic scope. New B. bassiana isolates from TPB described above and a commercial isolate were evaluated in laboratory bioassays against several key beneficial insect predators including a ladybug spp. (Hippodamia convergens), pirate bug adults and nymphs (Orius insidiosus), lacewing larvae (Chrysopa carne), praying mantids (Tenodera aridifolia sinensis), and an egg parasitoid of Lygus spp. (Anaphes ioles) in cooperation with Livy Williams (USDA-ARS, Stoneville, MS). Six formulation strategies were evaluated which involved the use of spray drying to produce lignin-coated spores for protection from solar radiation. Lignin-coated spore formulations were shown to protect spores from solar radiation, increasing spore survival by up to 20 times, and this formulation remained virulent to TPB. Subsequent bioassays were conducted to evaluate the contribution of spore uptake from a substrate to TPB mortality for the six
formulation strategies. Additional research was conduced on the use of fluidized bed drying to produce lignin coated spores for protection from solar radiation as a process for improving spore survival during drying through collaboration with Foster Agblevor, Donald Mullins, Herman Warren, and Larry Vaughan (Virginia Polytechnic Institute and State University). A study was conducted to evaluate the impact of cotton planting date on cotton aphid fungus epizootology. Four cotton planting dates were each replicated four times. Physical data (temperature and relative humidty) within the cotton canopy, cotton aphid populations, and infection levels were monitored at different heights within the cotton canopy for each planting date. The results of this experiment are still being analyzed. The results of this experiment may contribute to cultural control methods for augmenting N. fresenii epizootics and provide information useful in planning inoculative control strategies. C. Significant
Accomplishments/Activities that Support Special Target Populations: None. Progress Report: A new TPB trap-the first that does not require the use of sticky material to capture the insects-has been developed. Bypassing the need for sticky material should result in widespread usage of traps for TPB research, especially after the identification, isolation, and synthesis of TPB pheromones. Our TPB colony has been ridded of the microsporidian pathogen that plagued it, but bacterial contamination of bugs and artificial diet continues to hamper research. We are in the process of identifying the source, amount, and cure for the dietary contamination has shown the need for revising diet-making procedures and adding antibiotics to the artificial diet. New isolates of entomopathogenic fungi from TPB have been obtained, and the virulence of select isolates has been tested against TPB, WTPB, and select beneficial insects. New formulations for protecting spores from solar radiation have been
evaluated for UV-protection and virulence to TPB. Interactions between cotton planting dates and N. fresenii epizootics have been investigated. Project was certified on 03/27/03 by OQSR after undergoing NP 304 Ad Hoc Review. Title, objectives, investigators, and approach are revised to agree with certified Project Plan; termination date was extended to 8/31/2005. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. A new, non-sticky TPB trap, one of the major goals of the CRIS, has been developed. Further refinement of the trap and the eventual availability of synthetic TPB pheromone should result in a significant demand for such a trap. The potential for releasing sterile TPB and using new entomopathogenic fungi to control TPB populations especially while the bugs reside in alternate hosts prior to their entry into cotton fields is being studied. TPB attraction and response is also being investigated, and the new trap will
aid this research. 6. What do you expect to accomplish, year by year, over the next 3 years? We have made significant headway in TPB trap development and in our study of the potential for TPB control using mass-reared, sterilized bugs and entomopathogenic fungi. We expect to learn how competitive sterile TPB are compared to native bugs, especially with regard to sperm production, pheromone production, and response to pheromone and other attractants. New entomopathogenic fungi will be isolated from field-collected TPB. New isolates will be evaluated for virulence to TPB, WTPB, stink bugs, and beneficial insects. Isolates will be evaluated for infectivity potential under adverse environmental conditions such as high temperature and solar radiation. A few isolates from the combined collections of Michael McGuire and Jarrod Leland will be selected for scale-up production and field evaluation. Formulations will be improved that protect spores from solar radiation. Production of lignin
coated spores will be scaled-up to provide sufficient materials for field trials. 7. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? The tarnished plant bug trap should be available for research by the summer of 2004. Commercial use of the trap seems likely only after a reasonably-priced synthetic pheromone becomes commercially available. For the area-wide management of TPB with entomopathogenic fungi to be a success, a commercial partner would be needed for production of a mycoinsecticide. Jarrod Leland and Michael McGuire recently submitted a invention disclosure for a patent to the PWA patent committee, regarding the use of specific entomopathogenic fungal isolates in controlling Lygus spp.This will give potential commercial partners protection
should they decide to pursue further development of a Lygus specific mycoinsecticide in cooperation with USDA-ARS. Controlling TPB with mycoinsecticides would need to be competitive with regards to efficacy and cost with chemical insecticides and natural population control through the wild host plant management. Other factors such as the preservation of natural enemies and management of insecticide resistance would need to be factored into this cost/benefit analysis. A commercial producer of a mycoinsectide that is efficacious against TPB currently exists, however field trials with this commercial mycoinsecticide have had mixed results. Demonstrating that mycoinsecticides could be used to control populations in wild host plants at a viable economic cost would make this a more attractive market for commercial producers. Advances in formulation technology and selection of highly virulent, specific isolates, able to infect under field conditions with commercial production potential would
greatly advance the practical application of mycoinsecticides and make them a more competitive alternative to chemical control. Approaches to augmenting natural epizootics of N. fresenii could provide information to growers on cultural management practices. In addition, if it is demonstrated that natural epizootics may be jump-started through inoculative biocontrol, there may be a commercial interest in producing and disseminating inoculum for cotton growers. The greatest limitation to this as a commercial success is the inability to grow N. fresenii in vitro. 8. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: This does not replace your peer-reviewed publications listed below). Reed, J. "The Tarnished Enemy" June 2003. Cotton Farming Magazine. Both the sterility and the mycoinsecticide research was covered in this article.
Impacts
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Publications
- Villavaso, E.J., Mulrooney, J.E., McGovern, W.L. Boll weevil (Coleoptera: Curculionidae) bait sticks: Toxicity and Malathion content. Journal of Economic Entomology. 2003. v. 96. p. 311-321.
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