Research Project: Novel Approaches for Managing Key Pests of Peach and Pecan

Location: Fruit and Tree Nut Research

2021 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, as well as improved fundamental knowledge of entomopathogens: Subobjective 1a. Determine the efficacy of biocontrol agents in suppressing the pecan weevil. Subobjective 1b. Investigate the basic biology and ecology of biological control agents. Subobjective 1c. Investigate improved methods of nematode pheromone production. Objective 2: Develop control strategies for pecan aphids using banker plants, optimization of chlorosis-impeding plant bioregulators, and the use of microbial control agents: Subobjective 2a. Assessment of banker plants for control of pecan aphid spp. in orchards. Subobjective 2b. Optimize use of plant bioregulators to manage M. caryaefoliae injury. Subobjective 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, barriers, mating disruption and application of entomopathogenic nematodes: Subobjective 3a. Determine efficacy of reduced-risk insecticides against stink bugs. Subobjective 3b. Determine efficacy of physical and insecticidal barriers against peach pests. Subobjective 3c. Use mating disruption to manage sesiid borers. Subobjective 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 efficacy through improved delivery and formulation. Additionally, pertinent basic studies on entomopathogen foraging dynamics and production technology 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) implement efficacious microbial control tactics. Suppression of key peach pests via reduced-risk insecticides, physical and insecticidal barriers, mating disruption, and application of entomopathogenic nematodes will be examined. Anticipated products from this research include novel alternative pest management tactics involving microbial biocontrol agents, mating disruption, 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, such as pecan weevil and pecan aphids, using bio-insecticides were explored by ARS scientist in Byron, Georgia. An environmentally-friendly bio-insecticide “Grandevo” was found to control pecan weevil at levels equal to standard chemical insecticides, contribute to pecan aphid control, and growers have started to adopt the technology. An endophytic insect-killing fungus (living inside the tree) was introduced into pecan trees. The endophytic fungus suppressed pecan aphid populations and Phytophthora disease in a greenhouse setting; experiments were initiated by ARS scientist in Byron, Georgia, to determine the effects of pecan cultivar on the endophyte approach. Basic research on the behavior of beneficial insect-killing nematodes and their mass-production technology was implemented. Experiments were initiated by ARS scientist in Byron, Georgia, to compare strain effects for in vitro nematode production, and a grower-based in vivo production system was explored. In behavioral studies, the nematodes were found to continuously travel in groups like a pack of wolves seeking their insect prey; the nematodes were found to display “follow the leader” behavior. Addition of nematode specialized pheromones to biocontrol applications increased pest control efficacy by enhancing nematode movement and infectivity; an industry partner is now developing this patented technology. The first field tests to confirm the pheromone technology were initiated by ARS scientist in Byron, Georgia. Entomopathogenic (insect-killing) nematodes were discovered to provide high levels of control to the peachtree borer (a major peach pest). In prophylactic and curative applications the beneficial nematodes provided equal levels of control compared with chlorpyrifos. New research to optimize beneficial nematode rates and explore novel formulations to enhance nematode persistence were initiated by ARS scientist in Byron, Georgia. Formulation research on insect-killing fungi was also initiated; a novel nanoparticle formulation was discovered to provide substantial protection against UV radiation. The research on nematode and fungal bio-pesticides contributes to the goal of developing alternative biological solutions for control of key pecan and peach pests and has led to adoption by growers and industry. Aphids attacking pecan can be managed by natural enemies developing on the crap myrtle aphid on crape myrtle plants and then moving laterally to adjacent pecan trees. Flaring crape myrtle aphids is used as a means to build natural enemy populations in pecan orchards. When crape myrtle aphids have been consumed the natural enemies move to pecan and manage pecan-feeding aphids. As concerns the efficacy of gibberellic acid mitigating elicitation of leaf chlorosis, current studies are further elucidating the interaction of the black pecan aphid with pecan foliage treated with gibberellic acid. Peach research is targeting the brown stink bug through studies beginning to identify reduced-risk insecticides. Similarly, initiation of new research to determine the efficacy of barriers against stink bugs moving into peach orchards has begun. Even though peach growers are using mating disruption to manage sesiid pests attacking peach, further research was done to understand identified limitations to the pest management strategy, specifically how efficacious is mating disruption when used in older orchards with missing trees.

Accomplishments
1. Nanoparticle formulations enhance biopesticide efficacy. Environmentally friendly biopesticides, such as entomopathogenic (insect-killing) fungi can control various economically important insect pests such as pecan weevils. The efficacy of these biopesticides, however, can be limited due to sensitivity to ultraviolet radiation. Thus, it is critical to develop new formulations that protect the biopesticide organisms from environmental stress. ARS researchers at Byron, Georgia, and Israeli partners discovered that nanoparticle-based formulations protect biopesticides from ultraviolet radiation and thereby increase pest control efficacy. This technology can lead to improved sustainability in pest management practices.

2. A bacteria-based biopesticide controls pecan weevil and preserves natural enemies. The pecan weevil is a major pest of pecans. The insect is usually controlled with chemical insecticides, but these insecticides may be harmful to humans and the environment, kill beneficial natural enemies such as lady beetles, and cause flaring of pecan aphids (another group of important pecan pests). An environmentally safe biopesticide “Grandevo”, which is based on a naturally-occurring bacterium,was used by ARS scientists at Byron, Georgia, and caused equal levels of pecan weevil control compared with recommended chemical insecticides. Moreover, in field experiments, the biopesticide contributed to pecan aphid control and conserved beneficial natural enemies. Thus, the bacteria-based biopesticide is a viable eco-friendly tool for control of pecan weevil. Grower adoption has been initiated.

Review Publications
Shapiro Ilan, D.I., Goolsby, J. 2021. Evaluation of Barricade® to enhance survival entomopathogenic nematodes on cowhide. Journal of Invertebrate Pathology. 184. https://doi.org/10.1016/J.JIP.2021.107592.
Silva, M.S., Cardoso, J.M., Ferreira, M.E., Baldo, F.B., Silva, R.S., Chacon-Orozco, J.G., Shapiro Ilan, D.I., Hazir, S., Bueno, C.J., Garrigos-Leite, L. 2021. An assessment of steinernema rarum as a biocontrol agent in sugarcane with focus on sphenophorus levels, host-finding ability, compatibility with vinasse and field efficacy. Agriculture, Ecosystems and Environment. 11/500. https://doi.org/10.3390/agriculture11060500.
Usman, M., Gulzar, S., Wakil, W., Pinero, J., Leskey, T.C., Nixon, L., Hofman, C.O., Wu, S., Shapiro Ilan, D.I. 2020. Potential of entomopathogenic nematodes against the pupal stage of the apple maggot Rhagoletis pomonella (Walsh) (Diptera: Tephritidae). Journal of Nematology. 52:1-9. https://doi.org/10.21307/jofnem-2020-079.
Sandhi, R., Shapiro-Ilan, D., Reddy, G.V. 2020. Montana native Entomopathogenic Nematode Species against Limonius californicus (Coleoptera: Elateridae). Journal of Economic Entomology. 113:1-8. https://doi.org/10.1093/jee/toaa164.
Kaplan, F., Schiller, K.C., Shapiro Ilan, D.I. 2020. Dynamics of entomopathogenic nematode foraging and infectivity in microgravity. Nature. 6:20. https://doi.org/10.1038/s41526-020-00110-y.
Shan, S., Huang, C., Zhen, S., Ma, H., Gu, X., Jiang, Z., Sun, B., Chen, C., Shapiro Ilan, D.I., Ruan, W. 2020. Metabolites from symbiotic bacteria of entomopathogenic nematodes have antimicrobial effects against Pythium myriotylum. European Journal of Plant Pathology. 158/35-44. https://doi.org/10.1007/s10658-020-02053-2.
Gulzar, S., Usman, M., Wakil, W., Gulcu, B., Hazir, C., Karagoz, M., Hazir, S., Shapiro Ilan, D.I. 2020. Environmental tolerance of infective juveniles differs among nematodes arising from host cadaver versus aqueous suspension. Journal of Invertebrate Pathology. 175: 107452. https://doi.org/10.1016/j.jip.2020.107452.
Usman, M., Gulzar, S., Walkll, W., Wu, S., Pinero, J., Leskey, T.C., Nixon, L., Hofman, C.O., Toews, M., Shapiro Ilan, D.I. 2020. Virulence of entomopathogenic fungi to the Apple maggot Rhagoletis pomonella (Diptera: Tephritidae) and interactions with entomopathogenic nematodes. Journal of Economic Entomology. 113, 2627-2633. https://doi.org/10.1093/jee/toaa209.
Goolsby, J., Shapiro Ilan, D.I. 2020. Passive transfer of Steinernema riobrave entomopathogenic nematodes with implications for treatment of cattle fever tick-infested nilgai. Biocontrol Science and Technology. 12:1330-1339. https://doi.org/10.1080/09583157.2020.1817332.
Haelewaters, D., Hiller, T., Kemp, E.A., Van Wielink, P.S., Shapiro Ilan, D.I., Aime, M.C., Nedyed, O., Pfister, D.H., Cottrell, T.E. 2020. Mortality of native and invasive ladybirds co-infected by ectoparasitic and entomopathogenic fungi. PeerJ. 8/e10110. http://doi.org/10.7717/peerj.10110.
Wakil, W., Yasin, M., Shapiro Ilan, D.I. 2020. Synergistic interactions between two invertebrate pathogens: an endophytic fungus and an externally applied bacterium. Frontiers in Microbiology. 11, 522368. https://doi.org/10.3389/fmicb.2020.522368.
Wu, S., Toews, M.D., Hofman, C.O., Behle, R.W., Simmons, A.M., Shapiro Ilan, D.I. 2020. Environmental tolerance of entomopathogenic fungi: a new strain of cordyceps javanica isolated from a whitefly epizootic versus commercial fungal strains. Insects. 11(10). Article 711. https://doi.org/10.3390/insects11100711.
Chacón-Orozco, J.G., Bueno, C.J., Shapiro-Ilan, D., Hazir, S., Leite, L.G., and Harakava, R. 2020.Antifungal activity of Xenorhabdus spp. and Photorhabdus spp. against the soybean pathogenic Sclerotinia sclerotiorum. Scientific Reports, 10, Article number: 20649.
Fu, Y., Wang, W., Chen, C., Shan, S., Shapiro Ilan, D.I., Liu, Y., Cheng, W., Gu, X., Ruan, W. 2020. Chemotaxis of Steinernema carpocapsae to Galleria mellonella (L.) larvae infected by con- or hetero-specific entomopathogenic nematodes. Biocontrol Science and Technology. 31/299-313. https://doi.org/10.1080/09583157.2020.1853049.
Touray, M., Cimen, H., Sebnem, G., Ulug, D., Erdogus, D., Shapiro Ilan, D.I., Hazir, S. 2021. The impact of chemical nematicides on entomopathogenic nematode survival and infectivity. Journal of Nematology. 53/49. https://doi.org/10.21307/jofnem-2021-049.
Gulzar, S., Wakil, W., Shapiro Ilan, D.I. 2021. Combined effect of entomopathogens against thrips tabaci lindeman (thysanoptera: thripidae) under laboratory, greenhouse and field conditions. Insects. 12/456. https://doi.org/10.3390/insects12050456.
Cottrell, T.E., Balusu, R.R., Vinson, E., Wilkins, B., Fadamiro, H.Y., Tillman, P.G. 2020. Effect of trap color and residual attraction of a pheromone lure for monitoring stink bugs (hemiptera: pentatomidae). Journal of Entomological Science. 55/437-447. https://doi.org/10.18474/0749-8004-55.4.437.
Cottrell, T.E., Woods, B.W. 2020. Gibberellic acid decreases melanocallis caryaefoliae (hemiptera: aphididae) population density and chlorotic feeding injury to foliage in pecan orchards. Pest Management Science. 77/1512-1519. https://doi.org/10.1002/ps.6173.
Grabarczyk, E.E., Olson, D.M., Tillman, P.G., Hodges, A.C., Hodges, G., Horton, D.L., Cottrell, T.E. 2021. Spatiotemporal distribution of stink bugs (Hemiptera: Pentatomidae) in peach orchards and surronding habitat. Florida Entomologist. Vol. 104, No. 1 (March 2021).
Nalinci, E., Karagoz, M., Ulug, D., Gulsen, S., Cimen, H., Touray, M., Shapiro Ilan, D.I., Hazir, S. 2021. The effect of chemical insecticides on the scavenging performance of Steinernema carpocapsae: Direct effects and exposure to insects killed by chemical insecticides. Journal of Invertebrate Pathology. 184/107641. https://doi.org/10.1016/j.jip.2021.107641.
Slusher, E.K., Cottrell, T.E., Acebes-Doria, A.L. 2021. Effects of aphicides on pecan aphids and their parasitoids in pecan orchards. Insects. 12(3)241. https://doi.org/10.3390/insects12030241.