2013 Annual Report
1a.Objectives (from AD-416):
Identify chemical attractants (e.g., pheromones/kairomones and plant volatiles) for agriculturally important insect species (either pests or biocontrol agents for weed or insect pests) for which such knowledge is lacking or incomplete, determine the biological and environmental parameters for natural emission of the compounds, and synthesize or otherwise obtain them in quantities sufficient for field use. Characterize the behavioral responses toward the identified compounds under bioassay and field conditions, with special consideration to the development of practical management tools.
1b.Approach (from AD-416):
The overall goals of this proposed research are to identify compounds that are attractive to pest insects and beneficial insects and to develop these semiochemicals into practical applications such as monitoring tools and pest control strategies. The project focuses on insect species for which such information is lacking or incomplete. The target species belong to a diverse group of insects: The emerald ash borer (EAB), Agrilus planipennis, is a severe invasive buprestid pest of ash trees in North America. Host volatiles and essential oils contain several biologically active compounds useful for monitoring EAB. Purification and synthetic methods will be developed to obtain these target compounds in quantities necessary for field experiments. Three exotic parasitoids, Spathius agrili, Oobius agrili, and Tetrastichus planipennis have been released as possible EAB biocontrol agents. Semiochemicals involved in the parasitoid-host-tree complex will be identified focusing first on pheromones as attractants in monitoring the survival and establishment of newly released parasitoid populations. Diorhabda spp. are introduced biocontrol beetles for the invasive weedy tree, saltcedar (Tamarix spp.). Pheromone components for Diorhabda spp. are known, but the precise blend ratios for optimal attractiveness are still incomplete and will be further investigated. The lesser mealworm beetle (LMW), Alphitobius diaperinus is a global insect pest of commercially raised poultry. The pheromone blend of the LMW has recently been identified and can be synergized with poultry manure volatiles. However, knowledge on the correct blend composition is lacking. Optimized blends will be field-evaluated in order to develop a LMW control strategy. Users of the research results would be grower groups, regulatory agencies, land management agencies, businesses dealing with insect attractants, and other scientists.
The invasive emerald ash borer (EAB) beetle has destroyed tens of millions of ash trees in eighteen U.S. states and two Canadian provinces and the destructive force of this beetle is causing monetary losses to municipalities, property owners, nursery operators and forest products industries. In order to control this beetle several of its natural enemies have been released in the U.S. One of these natural enemies, Spathius agrili, a non-stinging parasitic wasp lays eggs on the larval stages of EAB, killing these larvae when developing into adults. In order to evaluate establishment of S. agrili in areas where it has been introduced, current methods to determine its presence in the field include felling ash trees and rearing out developing insects, or peeling bark to manually search for parasitized EAB. However, felling and peeling trees is destructive and highly labor-intensive. We explored the color preferences and other behaviors of adult wasps for the possible development of an attractant-baited trap for population sampling of S. agrili.
One of the major constraints to coffee production worldwide is the damage caused by the coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae). This small beetle is endemic to Central Africa and can now be found throughout most coffee producing countries. Annual losses have been estimated at $500 million yearly, although a recent study from Brazil estimates yearly losses in that country at $215 to $358 million per year, indicating that the $500 million figure is very conservative. Most of the life cycle is spent inside coffee berries, making this cryptic insect quite difficult to control both by chemical and non-chemical strategies. In lab bioassays, we have identified natural occurring compounds that inhibit the beetle from boring into the coffee berries.
Recently, the Tea Shot Hole Borer (TSHB) (Euwallacea fornicatus), a pest of tea and avocado, was discovered in Florida, and the closely related Polyphagous Shot Hole Borer (PSHB) (Euwallacea [=Xyleborus] new species) was detected in several varieties of avocado (Lauraceae) and multiple other tree species in Los Angeles and Orange Counties in California. Morphologically, these two ambrosia beetles are indistinguishable, but they carry different species of mutualistic phytopathogenic fungi, Fusarium sp., and are genetically divergent enough to be considered as potentially separate species. The phytopathogenic fungus they carry causes Fusarium Dieback in infected trees. The PSHB beetles are highly polyphagous, and attack over 200 tree species, the top eight of which make up 25% of all street trees in southern California. California’s $300 million-per-year avocado industry accounts for 90% of U.S. grown avocados, with Florida accounting for most of the rest. With the new presence of the PSHB in California and TSHB in Florida, the U.S. avocado industry faces a grave threat, similar to the avocado industry in Israel. We have started a project to detect and identified possible attractants for these beetles that can be used in beetle detection programs.
Determination of color preference and other behaviors for Spathius agrili. Spathius agrili is a natural enemy of the emerald ash borer, an invasive beetle pest from Asia that is causing widespread mortality of ash trees in the U.S. and Canada. ARS Crop Bioprotection Research Unit scientists at the National Center for Agricultural Utilization Research, Peoria, Illinois, together with scientists from Animal and Plant Health Inspection Service (APHIS), determined white to yellow color preferences for flight and landing behavior of adult wasps and used this color for the development of an attractant-baited trap for population sampling of S. agrili. This research created a more effective S. agrili trap.
Cooperband, M.F., Hartness, A., Lelito, J.P., Cosse, A.A. 2013. Landing surface color preferences of Spathius agrili (Hymenoptera: Braconidae), a parasitoid of emerald ash borer, Agrilus planipennis (Coleoptera: Buprestidae). Journal of Insect Behavior. 26(5):721-729. DOI:10.1007/s10905-013-9387-3.