Location: Fruit and Tree Nut Research
2018 Annual Report
Objectives
Objective 1: Develop alternative control strategies for the pecan weevil based on enhanced production, formulation delivery and efficacy of microbial control agents, and improved fundamental knowledge of natural enemies:
Sub-objective 1a: determine the efficacy of biocontrol agents in suppressing the pecan weevil.
Sub-objective1b: investigate the basic biology and ecology of biological control agents.
Sub-objective1c: investigate improved methods of nematode production.
Objective 2: Develop alternative control strategies for pecan aphids using banker plants, optimization of chlorosis-impeding plant bioregulators, and microbial control agents:
Sub-objective 2a: assessment of banker plants for control of pecan aphid spp. in orchards.
Sub-objective 2b: optimize orchard use of plant bioregulators to manage M. caryaefoliae injury.
Sub-objective 2c: implement microbial control agents for pecan aphid management.
Objective 3: Develop alternative control strategies for key peach pests (plum curculio, sesiid borers, and stink bugs) via reduced-risk insecticides, repellents, barriers, mating disruption, and application of entomopathogenic nematodes.
Sub-objective 3a: control stink bugs with reduced-risk insecticides.
Sub-objective 3b: assess repellants and barriers for management of peach pests.
Sub-objective 3c: mating disruption to manage sesiids borers.
Sub-objective 3d: develop entomopathogenic nematodes for control of key peach pests.
Approach
Pecan and peach are important horticultural crops that can suffer severe losses in yield due to insect damage. The overall goal of this project is to provide economically and environmentally sound pest management strategies for control of key insect pests of pecan and peach. Objectives include alternative control strategies for key pecan pests (pecan weevil and pecan aphids) and key peach pests (plum curculio, sesiid borers, and stink bugs). Suppression of pecan weevil will focus on developing microbial control tactics including integrated entomopathogen applications and enhanced entomopathogen persistence through the use of cover crops and improved delivery. Additionally, pertinent basic studies on entomopathogen infection dynamics and delivery will be addressed. Management strategies for pecan aphids will 1) optimize usage of chlorosis-impeding plant bioregulators against the black pecan aphid, 2) incorporate banker plants into orchards for pecan aphid management and 3) identify and implement efficacious microbial control tactics. Suppression of key peach pests via reduced-risk insecticides, repellents, barriers, mating disruption, and application of entomopathogenic nematodes will be examined. Anticipated products from this research include novel alternative pest management tactics involving biocontrol agents, plant bioregulators, or other innovative strategies, improved methods for production, formulation, and delivery of biocontrol agents, and the filling of key knowledge gaps in basic insect pest and natural enemy biology and ecology.
Progress Report
Novel strategies for controlling key pecan pests, pecan weevil, using bio-insecticides were explored. New research was initiated to investigate the potential to inoculate pecan trees with endophytic insect-killing fungi. The endophytic fungi (living inside the tree) can then be tested for the ability to contribute to insect and disease suppression. The insect-killing fungus called Beauveria bassiana was for the first time ever successfully established as an endophyte in pecan seedlings. Additionally, experiments were conducted to optimize the production of beneficial entomopathogenic (insect-killing) nematodes by improving their production media, formulation and genetically stabilizing the nematodes via generation of homozygous purebred lines. These biocontrol approaches are promising for use against pecan weevil as well as key peach pests; grower adoption of the tactics has been initiated and has potential for expansion. Furthermore, fundamental research on beneficial nematodes was conducted and resulted in a new discovery indicating that these nematodes continually move in soil as a group. The research on nematode and bacterial pesticides contributes to the goal of developing alternative biological solutions for control of key pecan and peach pests.
Research was continued that evaluates the efficacy of using gibberellic acid (GA3) applied to pecan foliage as part of a black pecan aphid management strategy. Replicated, large plot studies show that foliar application of GA3 mitigates the ability of the black pecan aphid to elicit chlorotic feeding injury on leaves. Results of this novel research are adapted and used by more commercial pecan growers each year.
Collaborative research on the southward-moving brown marmorated stink bug showed that predation and especially parasitism of brown marmorated stink bug eggs is much higher than reported in the northeastern U.S. Numerous native parasite species were documented to attack brown marmorated stink bug eggs.
Areawide mating disruption research to control peachtree borer and lesser peachtree borer has been adopted by southeastern U.S. peach growers. During 2018, 3,500 acres of commercial peach are under mating disruption as a result of this research.
Accomplishments
1. Peach growers adopt areawide mating disruption to manage borers. Conventional control of the peachtree borer and lesser peachtree borer has been difficult due to changes in insecticide labelling and the very long season (up to nine months) over which these pests must be controlled. Research by an ARS researcher at Byron, Georgia, and a collaborator has demonstrated that an areawide mating disruption approach provides control of these pests. The success of the project has led to the adoption of mating disruption of these pests by southeastern peach growers. During 2018, 3,500 acres of commercial peach are under mating disruption because of this research.
2. Beneficial worms movement through soil. Beneficial nematodes (small round worms) are natural bio-pesticides that attack and kill a wide variety of economically important insect pests such as pecan weevil and peachtree borer. Improved understanding of the nematode’s behavior will enhance their use as natural pest control agents. ARS researchers at Byron, Georgia, and colleagues studied movement behavior and discovered that beneficial nematodes disperse continuously through soil in groups, like a pack of wolves seeking their prey. Based on this discovery, ARS, university and industry partners are now investigating the pheromone signals that control the nematode behavior; these pheromone signals can then be used to direct and improve biological insect control. The results advance scientific knowledge in animal behavior and parasitology, and will lead to safe and effective pest management strategies.
3. Purebred worms last longer and are more effective. Beneficial nematodes (small round worms) are natural bio-pesticides that can kill a wide variety of economically important insect pests such as pecan weevil and peachtree borer. However, long-term mass production of these nematodes can lead to genetic deterioration and inbreeding, which reduces the nematode’s efficiency in controlling insect pests. ARS Researchers at Byron, Georgia, along with industry and university colleagues discovered that creating purebred lines of beneficial nematodes deters trait deterioration thereby making them more amenable to mass production. Moreover, the researchers found that isolation of nematodes from environmentally extreme targeted areas can bring superior traits to the table. For example, nematodes with superior cold tolerance were discovered in cold regions of Canada. The team demonstrated how both approaches, targeted discovery of new nematodes combined with creation of purebred lines, results in long-lasting nematodes and enhanced pest control efficacy. The purebred line approach is being adopted by industry and researchers around the globe.
4. Management of stink bugs on orchard crops. Many species of stink bugs cause economic injury to orchard crops. In the southeastern U.S., the brown stink bug is a serious pest of many crops, including peach and pecan. An ARS researcher at Byron, Georgia, and collaborator tested various insecticides against this pest and identified varying levels of brown stink bug control for the different insecticides tested. These results help growers select products that provide expected control of stink bug pests.
Review Publications
Shapiro Ilan, D.I., Cottrell, T.E., Bock, C.H., Mai, K.T., Boykin, D.L., Wells, L., Hudson, W.G., Mizell III, R.F. 2017. Control of pecan weevil with microbial biopesticides. Environmental Entomology. 46(6):1299-1304. https://doi:10.1093/ee/nvx144.
Sharifi-Far, S., Shapiro Ilan, D.I., Brownbridge, M., Hallett, R.H. 2018. The combined approach of strain discovery and the inbred line technique for improving control of Delia radicum with Heterorhabditis bacteriophora. Biological Control. 118:37-43. https://doi.org/10.1016/j.biocontrol.2017.12.004.
Hazir, S., Shapiro Ilan, D.I., Bock, C.H., Leite, L. 2017. Trans-cinnamic acid and Xenorhabdus szentirmaii metabolites synergize the potency of some commercial fungicides. Journal of Invertebrate Pathology. 145:1-8. https://doi:10.1016/j.jip.2017.03.007.
Wakil, W., Yasin, M., Shapiro Ilan, D.I. 2017. Effects of single and combined applications of entomopathogenic fungi and nematodes against Rhynchophorus ferrugineus (Olivier). Scientific Reports. 7:5971. https://doi.org/10.1038/s41598-017-05615-3.
Singh, N., Goolsby, J., Shapiro Ilan, D.I., Miller, R., Thomas, D.B., Klafke, G., Tidwell, J.P., Racelis, A., Grewal, P., Perez De Leon, A.A. 2018. Efficacy of entomopathogenic nematodes (Rhabditida: Heterorhabditidae and Steinernematidae) against engorged females of the cattle fever tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae). Southwestern Entomologist. 43(1):1-17. https://doi.org/10.3958/059.043.0119.
Singh, N., Goolsby, J., Shapiro Ilan, D.I., Setamou, M., Perez De Leon, A.A. 2018. Effect of immersion time on efficacy of entomopathogenic nematodes against engorged females of Cattle Fever Tick, Rhipicephalus (Boophilus) microplus. Experimental and Applied Acarology. 43(1):19-28. https://doi.org/10.3958/059.043.0120.
Geisert, R.W., Cheruiyot, D.J., Hibbard, B.E., Shapiro Ilan, D.I., Shelby, K., Coudron, T.A. 2018. Comparative assessment of four steinernematidae and three heterorhabditidae species for infectivity of larval diabrotica virgifera virgifera. Journal of Economic Entomology. 111(2):542-548. https://doi.org/10.1093/jee/tox372.
Tobias, N.J., Wolff, H., Djahanschiri, B., Grundmann, F., Kronenwerth, M., Shi, Y.M., Simonyi, S., Grun, P., Shapiro Ilan, D.I., Pidot, S.J., Stinear, T.P., Ebersberger, I., Bode, H.B. 2017. Natural product diversity associated with the nematode symbionts Photorhabdus and Xenorhabdus. Nature Microbiology. 2(12):1676-1685. https://doi:10.1038/s41564-017-0039-9.
Ruan, W., Shapiro Ilan, D.I., Lewis, E., Kaplan, F., Alborn, H.T., Gu, X., Schliekelman, P. 2018. Movement patterns in entomopathogenic nematodes: continuous vs. temporal. Journal of Invertebrate Pathology. 151:137-143. https://doi:10.1016/j.jip.2017.11.010.
Leite, L., Shapiro Ilan, D.I., Hazir, S., Jackson, M.A. 2017. Effect of inoculum age and physical parameters on in vitro culture of the entomopathogenic nematode Steinernema feltiae. Journal of Helminthology. 91(6):686-695. https://doi:10.1017/S0022149X16000821.
Del Pino, F.G., Morton, A., Shapiro Ilan, D.I. 2018. Entomopathogenic nematodes as biological control agents of tomato. In: Wakil, W., Brust, G.E., and Perring, T.M., editors. Sustainable Management of Arthropod Pests of Tomato Pests. London, UK: London Academic Press. p. 269–282. https://doi.org/10.1016/B978-0-12-802441-6.00012-7.
Shapiro-Ilan, D. I., Hiltpold, I., and Lewis, E. E. 2018. Ecology of Invertebrate Pathogens: Nematodes In: Hajek, A. E & Shapiro-Ilan, D. I., editors. Ecology of Invertebrate Diseases. Hoboken, NJ: John Wiley & Sons, p. 415-440.
Dara, S. K., Goble, T. A., and Shapiro-Ilan, D. I. 2018. Leveraging the ecology of invertebrate pathogens in microbial control. In: Hajek, A. E. & Shapiro-Ilan, D.I., editors. Ecology of Invertebrate Diseases. Hoboken, NJ: John Wiley & Sons. p. 469-494.
Hajek, A. E & Shapiro-Ilan, D. I. 2018. Ecology of Invertebrate Diseases. Hoboken, NJ: John Wiley & Sons. 657 p.
Schmidt, J., Shapiro Ilan, D.I., Graham, C., Barwick, S., Sparks Jr., A., Riley, D. 2018. Entomopathogenic nematodes and fungi virulence to cowpea curculio (Coleoptera: Curculionidae) larvae. Journal of Entomological Science. 53(2):152-161. https://doi.org/10.18474/JES17-65.1.
Cottrell, T.E., Tillman, P.G. 2017. Four species of lady beetles (Coleoptera: Coccinellidae) exhibit limited predation on Nezara viridula (Hemiptera: Pentatomidae) eggs and nymphs. Biological Control. 114:73-78. https://doi.org/10.1016/j.biocontrol.2017.08.005.
Tillman, P.G., Buntin, D., Cottrell, T.E. 2017. First report of seasonal trap capture for Halyomorpha halys (Stal) Hemiptera: Pentatomidae) and native stink bugs in central Georgia. Journal of Entomological Science. 52:455-459. https://doi.org/10.18474/JES17-56.1.
Cottrell, T.E., Ree, W. 2016. Assays of Orchard-Applied Insecticides on the Brown Stink Bug (Hemiptera: Pentatomidae) Feeding on Pecan. Journal of Entomological Science. 51(3):179-198.
