Location: Crop Bioprotection Research2016 Annual Report
1. Demonstrate production potential for baculovirus for insect control (such as black cutworm MNPV), evaluate formulations for storage stability and residual efficacy, and identify and evaluate insect semiochemicals such as attractants or feeding stimulants that can be integrated into formulations to improve control of major insect pests of turf or other crops. 2. Determine the relationship between microbial communities and the characteristics of weeds (such as bindweed, medusahead grass, or quack grass) that make them harmful to turf, natural ecosystems, and agricultural commodities. 3. Identify viruses that can target potential key endophytes or microorganisms that contribute negative characteristics of weeds. 4. Identify, describe, and preserve microorganisms isolated from weeds as part of the characterization of microbial communities associated with important weeds.
Grasses planted as turf and pasture represent a commodity that has been underserved when considering the use of biological control based on microbial agents. For urban and athletic turf grasses, a newly discovered baculovirus offers the opportunity to develop a biological pesticide for control of the black cutworm. Research will focus on basic and applied aspects of production, formulation, and efficacy of this baculovirus for development as a biological insecticide. Invasive weed species among range grasses such as Medusahead may obtain enhanced fitness as a result of associations with endophytic microbes. Research will utilize classic microbial and newly developed molecular techniques to characterize endophytic microbes of the weedy plants and identify those providing competitive advantages to the weeds. Subsequent research will strive to discover mycoviruses to attach the endophytes of the weedy plant, to convert the competitive advantage back to the desired crop plant.
Substantial progress has been made in the first year of this research project. For Objective 1, important factors for in vivo production of the black cutworm baculovirus has been evaluated in order to optimize yield of this beneficial microbe. Larval age, exposure dosage, larval diet, and incubation temperature all impact the amount of wild-type virus produced by infected larvae. In addition, optimal conditions for production of selected virus isolates were also determined. Isolates with a specific gene deletion are known to provide faster kill of the pest insect, but tend to have lower levels of production relative to wild-type virus. Characterizing the impact of higher production on kill-rate will guide the selection of the isolates for the most effective pest control application. We have made significant progress in Objective 2 by isolating more than 350 fungal strains from the invasive weed, medusahead (Taeniatherum caput-medusae). The plants were sampled from their invaded range in the western United States (U.S.) and from their native range in Europe. We successfully obtained fungal isolates from the roots, seeds, stems, and leaves from both invaded (U.S.) and native (Europe) plant samples. In addition, DNA samples have been extracted from all of the plant tissues for future analysis of the microbial communities based on high throughput DNA sequencing techniques. We have made significant progress in Objective 4 by establishing an inventory system and strain database to manage newly isolated fungal strains. All of the strains isolated from this year’s field work have been accessioned into the database and are available for future research needs.
1. Research on the benefits provided to plants by fungi that live symbiotically within living plant tissue (endophytes) is a new and emerging science that generally focuses on improving crop plants. It is likely that the endophytes provide an ecological advantage to invasive weeds, although these mechanisms have yet to be discovered. As the initial phase of this research on weed endophytes, we have successfully collected, identified, cultured, and stored over 350 fungal isolates from the invasive noxious weed medusahead to establish a culture collection as a specific resource for studying symbiotic interactions. This collection will support the ultimate research goal of developing weed control by selective manipulation of the endophytic fauna. Defining parameters for economical production of entomopathogens to be used as biological insecticides remains a major factor limiting successful commercialization. In support of developing the baculovirus AgipMNPV as a biopesticide for control of the black cutworm infesting turf grass grown for golf tees and greens, the impact of important in vivo production factors have been characterized to maximize production of virus particles including: selection of the artificial diet, age (size) of the exposed larvae, exposure dosage, and incubation temperature. Evaluating virus products, for both the number of particles produced and the insecticidal activity of those particles, insures the quality of the active agent for subsequent research for development of this agent as an ecologically benign pest control technology for use on highly managed turf grass.
Behle, R.W., Richmond, D.S., Jackson, M.A., Dunlap, C.A. 2015. Evaluation of Metarhizium brunneum F52 (Hypocreales: Clavicipitaceae) for control of Japanese beetle larvae in turfgrass. Journal of Economic Entomology. 108(4):1587-1595. doi: http://dx.doi.org/10.1093/jee/tov176.
Dunlap, C.A. 2015. Phylogenomic analysis shows that ‘Bacillus vanillea’ is a later heterotypic synonym of Bacillus siamensis. International Journal of Systematic and Evolutionary Microbiology. 65(10):3507-3510.
Dunlap, C.A., Kwon, S.W., Rooney, A.P., Kim, S.J. 2015. Bacillus paralicheniformis sp. nov., isolated from fermented soybean paste. International Journal of Systematic and Evolutionary Microbiology. 65(10):3487-3492.
Kim, S.J., Dunlap, C.A., Kwon, S.W., Rooney, A.P. 2015. Bacillus glycinifermentans sp. nov., isolated from fermented soybean paste. International Journal of Systematic and Evolutionary Microbiology. 65(10):3586-3590.
Mascarin, G.M., Jackson, M.A., Kobori, N.N., Behle, R.W., Dunlap, C.A., Delaibera, I. 2015. Glucose concentration alters dissolved oxygen levels in liquid cultures of Beauveria bassiana and affects formation and bioefficacy of blastospores. Applied Microbiology and Biotechnology. 99(16):6653-6665. doi: 10.1007/s00253-015-6620-3.
Qayyum, M.A., Wakil, W., Arif, M.J., Sahi, S.T., Dunlap, C.A. 2015. Infection of Helicoverpa armigera by endophytic Beauveria bassiana colonizing tomato plants. Biological Control. 90:200-207.
Dito, D.F., Shapiro-Ilan, D.I., Dunlap, C.A., Behle, R.W., Lewis, E.E. 2016. Enhanced biological control potential of the entomopathogenic nematode, Steinernema carpocapsae, applied with a protective gel formulation. Biocontrol Science and Technology. 26(6):835–848.
Dunlap, C.A., Kim, S.J., Kwon, S.W., Rooney, A.P. 2016. Bacillus velezensis is not a later heterotypic synonym of Bacillus amyloliquefaciens; Bacillus methylotrophicus, Bacillus amyloliquefaciens subsp plantarum and ‘Bacillus oryzicola’ are later heterotypic synonyms of Bacillus velezensis based on phylogenomics. International Journal of Systematic and Evolutionary Microbiology. 66(3):1212-1217. doi: 10.1099/ijsem.0.000858.
Behle, R.W., Goett, E.J. 2016. Dosage response mortality of Japanese beetle, masked chafer, and June beetle (Coleoptera: Scarabaeidae) adults when exposed to experimental and commercially available granules containing Metarhizium brunneum. Journal of Economic Entomology. 103(3):1109-1115. doi: 10.1093/jee/tow080.