Location: Fruit and Nut Research2013 Annual Report
1a. Objectives (from AD-416):
1. Develop alternative control strategies for the pecan weevil: (1.1) Determine the efficacy of biocontrol agents such as entomopathogenic nematodes (Steinernema and Heterorhabditis spp.) and entomopathogenic fungi (Hypocreales), and (1.2) investigate the basic biology and ecology of these agents to enhance efficacy. (1.3) Investigate improved methods of production, formulation, and delivery of these biological control agents, and integrate optimum biocontrol tactics with other management strategies. 2: Develop alternative control strategies for black pecan aphids through (2.1) assessment of pecan susceptibility (foliar damage ratings, aphid development, and aphid mortality), (2.2) use of plant growth regulators, and (2.3) microbial control agents including Beauveria, Isaria or Metarhizium spp. 3: Develop alternative control strategies for key peach pests (plum curculio, peachtree borers, and stink bugs) via (3.1) reduced-risk insecticides (such as thiamethoxam, flonicamid, and novaluron), (3.2) mating disruption, and (3.3) entomopathogenic nematodes.
1b. Approach (from AD-416):
Suppression of pecan weevil will focus on developing microbial control tactics including multi-stage entomopathogen applications, enhanced entomopathogen persistence through the use of cover crops, and synergism via combinations of entomopathogens and chemical insecticides. Additionally, pertinent basic studies on entomopathogens will be addressed. Management strategies for the black pecan aphid will use a long term approach to screen pecan for low aphid susceptibility (for use in pecan breeding), whereas, a short term approach will use plant growth regulators and microbial control. Suppression of key peach pests via reduced-risk insecticides, mating disruption, and entomopathogenic nematodes will be examined.
3. Progress Report:
This report serves to document progress of research conducted under in house project 6606-22000-22-00D. Novel strategies for controlling a key pecan pest, pecan weevil, using beneficial nematodes were investigated as were new methods of applying beneficial fungi (e.g., with a compost amendment or other fertilizers) and suppression using a bacteria-based bio-insecticide. Additionally, field experiments measured the efficacy of entomopathogenic nematodes in suppressing key peach pests (e.g., plum curculio and peachtree borer). 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 was conducted to explore group dispersal behavior in beneficial nematodes, identify novel host-finding cues, and stabilization of beneficial biocontrol traits. Research progress was continued toward screening pecan germplasm for resistance to the black pecan aphid. Additionally a demonstration orchard showed the utility of using plant growth regulators against the black pecan aphid and again, no appreciable impact on the subsequent year’s return bloom of pecan was indicated. Insecticide assays continue to identify superior products for management of stink bugs and plum curculio. Research regarding mating disruption for management of the lesser peach tree borer shows that potential for managing this serious peach pest using mating disruption will need to be done at an area wide level.
1. Electromagnetic fields as a novel cue in beneficial nematodes foraging behavior. Beneficial insect-killing nematodes are safe environmentally friendly natural insecticides. To maximize pest control efficacy, it is important to understand the basic biology of these nematodes. ARS scientists from the Southeastern Fruit and Tree Nut Research lab, Byron, Georgia have been investigating the basis for how nematodes find an insect pest to attack in the soil. The researchers discovered that the nematodes respond to small electrical currents, electrical fields as well as magnetic fields; this may be one way that the nematodes cue into their host or their host’s habitat. Identification of factors that affect nematode infection and host-finding leads to enhanced insect suppression.
2. Enhancement of lady beetles in orchards. Lady beetles contribute to natural aphid control in orchards. An ARS scientist at the Southeastern Fruit and Tree Nut Research Laboratory has researched a way to increase lady beetle density in orchards. Lady beetles were not attracted to commercially available lady beetle lures but were preferentially captured in yellow pyramid traps compared with other colors. Using these yellow traps or similar yellow materials, the scientist postulates that lady beetle density can be locally increased in orchards or other agricultural settings such as gardens or row crops.
3. Management of stink bugs attacking orchard crops. Stink bugs are serious pests of orchard crops and management is often difficult. An ARS scientist at the Southeastern Fruit and Tree Nut Research Laboratory along with collaborators from the University of Georgia and Texas A&M University conducted tests of labeled insecticides against the brown stink bug attacking pecan and peach. The researchers identified the labeled insecticides that provided the best control of the brown stink bug on both pecan and peach. These results are directly applicable to combating the brown marmorated stink bug when it establishes in Georgia.
Shapiro Ilan, D.I., Gardner, W., Wells, L., Cottrell, T.E., Behle, R.W., Wood, B.W. 2013. Effects of entomopathogenic fungus species, and impact of fertilizers, on biological control of pecan weevil (Coleoptera: Curculionidae). Environmental Entomology. 42:253-261.