1a. Objectives (from AD-416):
Objective 1: Develop new knowledge of the behavior, genetics, systematics, physiology, ecology, and biochemistry of the insect pests of apple, pear, and cherry, and their natural enemies, that will aid in the discovery, development, and application of management methods and technologies. Sub-objective 1A: Evaluate habitat modifications and predation as factors in pest insect suppression. Sub objective 1B: Determine morphological characters that can be used to discriminate apple and snowberry maggot flies. Objective 2: Identify genes, receptor proteins, and respective ligands that are critical to codling moth development and reproduction. Objective 3: Discover and develop chemical attractants for codling moth, fruit flies, pear psylla, and other insect pests of temperate tree fruits and their natural enemies. Sub-objective 3A: Determine attractiveness of semiochemicals for codling moth and other pests. Sub-objective 3B: Optimize the pear psylla sex pheromone and other pest lures. Objective 4: Determine the impact of pest management and cultural practices on beneficial insects to improve biological control of the codling moth, pear psylla, and other insect pests of temperate tree fruits. Objective 5: Develop systems approaches involving combinations of various methods and technologies, both for management of codling moth in suburban and agricultural settings, and to reduce the probability of insects infesting fruit that is packed and shipped domestically and internationally. Sub-objective 5A: Implement a monitoring-intensive management program for codling moth that reduces the use of insecticides. Sub-objective 5B: Develop computer modeling of codling moth quarantine risk. Sub-objective 5C: Evaluate brown sugar and hot water methods for the detection of cherry fruit fly larvae in cherries. Objective 6: Develop applications of insect pathogens, attract and kill technology, and disruption techniques to control codling moth and other pests of temperate tree fruits. Sub-objective 6A: Develop attract and kill station designs for managing codling moth and other pests. Sub-Objective 6B: Develop applications of entomopathogens for control of codling moth.
1b. Approach (from AD-416):
Analysis of DNA sequences in the gut contents of arthropod predators in orchards will assess their consumption of orchard pests in order to rank their importance to biological control. Extra-orchard hedgerows of native plants will be studied for potential to improve overwintering of parasites and predators of orchard insect pests. A combination of morphological shapes will be used to determine best diagnostic traits for identifying problematic species of fruit flies. Protein receptors and their encoding genes will be identified, and their corresponding ligands will be determined in support of work to develop species specific behavioral and physiological modifying analogs for use in pest management. Chemical attractants from host plants of pest insects will be identified and developed as lures for traps and baits. Pear psylla pheromone will be developed as a lure for field use through comparison of pheromone formulations, doses, and trap designs. Sublethal and delayed effects of pesticides on spiders will be determined, including impact on spider reproduction. Information from global positioning systems will be used to identify, evaluate and manage pest hot spots in orchards. Traps baited with kairomonal attractants will be tested as a strategy to reduce codling moth populations in orchards, and manage codling moth populations through the removal of female moths captured in traps. The risks of introduction and establishment of codling moth in other countries will be modeled mathematically to determine important gaps in our knowledge of the pest biology. Sugar solutions will be tested as a means to float cherry fruit fly larvae from fruit as a potential detection method. Attract and kill stations will be designed and evaluated as a means to manage codling moth. Replacing 5352-22000-019-00D (October 2010)
3. Progress Report:
Morphometric methods were used to classify apple maggot fly, snowberry maggot fly, and their hybrids using body shape traits. Ninety percent of hybrid female flies had novel wing shapes not found in parental flies. Wings of hybrid male flies were less distinctive. Results suggest that wing shape can be used to identify female hybrid flies. Marked differences in size and pigmentation of bacteriomes of male and female pear psylla indicated that insect gender should be considered in studies of bacteriome-associated symbionts. A novel trap baited with the sex pheromones of oriental fruit moth and codling moth and a liquid bait improved seasonal monitoring of both moths. Adoption of this new lure-trap design should allow growers to adopt action thresholds and reduce unnecessary use of insecticides. The common bread yeast and several wild yeasts enhanced larval codling moth feeding which might improve the pesticidal efficacy of a virus and an insect growth regulator. Improved efficacy of the virus could increase grower adoption and reduce sprays to manage secondary pests. Codling moth is a major quarantine pest in apples destined for Asian-Pacific markets. It was demonstrated that due to the short duration of chilling days and the short day length, codling moth could not successfully complete development in Taiwan, or any other country with similar climate and day lengths. As a result, the ‘Three Strikes’ policy of quarantining U.S. apples following 3 codling moth finds was eliminated in Taiwan, saving the apple industry an estimated $30,000,000 a year. Gene transcripts encoding three Neuropeptide F family peptides and their receptors were cloned from codling moth, and the receptors stably expressed in CHO cells. Gene transcripts encoding nicotinic acetylcholine receptors (20), G protein coupled receptors (95), and detoxification enzymes (166) have been identified in a codling moth head transcriptome. A cell-based assay to identify pheromone receptor/ligand interactions has been developed. Molecular analyses showed European earwig, ground beetles and spiders are major predators of codling moth. New DNA probes and protocols have been designed to support pest diagnosis for the system approach for export of cherries. Two new insecticides used in tree fruits were shown to be safe to beneficial insects. Yellow traps baited with the sex pheromone of pear psylla attracted overwintered male winterform psyllids. A combination of GC-MS, GC-EAD, and olfactometer techniques were used to identify the attractive chemicals in wine and vinegar baits used to trap the spotted wing drosophila. N-butyl sulfide was demonstrated as a lure for codling moth; together with acetic acid and pear ester, which constitutes a new superior female lure.
1. A new synthetic chemical lure for spotted wing drosophila. The spotted wing drosophila is a new invasive pest of soft fruits, originating in Asia but spreading through much of North America and Europe. ARS researchers at Wapato, Washington, working with scientists at ARS Poplarville, Mississippi, and the Oregon State Department of Agriculture determined that four compounds isolated and identified from volatiles of wine and vinegar are critical to a feeding attractant lure for spotted wing drosophila. Additional work provided a controlled release dispenser that is cheaper and simpler than predecessors and further improved the power and longevity of the attractant. This lure will be used for detection, monitoring, and potentially managing spotted wing drosophila in numerous fruit crops in the U.S.
2. Fate of codling moth in apples exported to tropical countries. Codling moth is a major quarantine pest in apples destined for Asian-Pacific markets. It was demonstrated that due to the short duration of chilling days and the short day length, codling moth could not successfully complete development in Taiwan, or any other country with similar climate and day lengths. In bilateral discussions, USDA-APHIS prsented these research results to Taiwan in their renegotiation of the 'Three-Strikes' policy. As a result, the ‘Three Strikes’ policy was eliminated in Taiwan, saving the apple industry an estimated $30,000,000 a year.
3. Determination of the codling moth head transcriptome. Physiological functions are important for insect survival and most of these functions are regulated by the brain. Because these critical physiological functions are usually regulated by proteins, many insect control agents target proteins present in the brain and nervous system. There is not much information available about the proteins present in the codling moth brain or the genes that encode for them. ARS researchers at Wapato, Washington, in collaboration with scientists at Washington State University, Pullman, Washington, generated a transcriptome of RNAs expressed in the codling moth head to identify the proteins present in this insect’s brain. Analysis of the transcriptome has led to the identification of gene transcripts encoding proteins that regulate most major physiological functions, as well as all of the targets of agents used in codling moth control programs. This information is currently being applied to study the molecular mechanisms of insecticide resistance, and will be used to identify new targets for future control agent development.
4. New kairomone lure for codling moth. The codling moth is a key insect pest of apple, pear and walnut. Non-pesticidal methods are needed for organic and soft management programs. ARS researchers at Wapato, Washington, developed a superior lure for female codling moths based on combining acetic acid, pear ester, and N-butyl sulfide. This lure holds promise for application to attract-and-kill strategies that depend on a powerful attractant to bring moths into point sources, in place of broadcast application of pesticide to contact and kill insect pests.
5. Neo-sex chromosomes and adaptive potential in tortricid pests. Scientists from the USDA, ARS, collaborated with scientists from the Czech Republic and Japan to map the Z-sex chromosome of codling moth. They found that the Z-chromosome arose from the fusion of the ancestral Z-chromosome with an autosome corresponding to chromosome 15 in the Bombyx mori, the silk moth, reference genome. This fusion brought several detoxification and pesticide resistance genes into the Z-sex chromosome. This research contributes to the management of tortricid pests through better understanding of the underlying genetics of pesticide resistance.
6. Physiological aspects of western cherry fruit fly diapause. Researchers at the USDA-ARS laboratory in Wapato, Washington, examined the physiological responses of this pest in relation to heat stress, duration of chilling, rearing temperature, day length, and humidity. Pupae not receiving 15 weeks of chilling needed more than 4000 degree days to complete diapause. Upper thermal limits of both adults and pupae were determined using differential scanning calorimetry and indicated that climates experiencing temperatures greater than 40°C are not suitable for this pest. These data were used in ecological niche and pest risk models to predict the potential for this pest to spread to other regions. This information has already been used to renegotiate the interstate movement of sweet cherries from the Pacific Northwest to California.
7. Addition of active yeasts to improve granulosis virus insecticides for codling moth. The granulosis virus is a highly selective biological control agent for codling moth and its use can minimize seasonal disruptions of biological control of secondary orchard pests. Unfortunately, the efficacy of this virus is moderate partially because codling moth is an internal fruit feeder and does not ingest sufficient virus to kill the larva before the fruit are injured. The addition of the common bread yeast or wild yeasts collected from codling moth-infested fruits with sugar was shown to significantly improve the activity of the virus through enhanced rates of feeding. This improved efficacy of the virus should translate into increased rates of grower adoption and will help to minimize the need for additional sprays to manage secondary pests.
8. Improved lure for monitoring oriental fruit moth. The oriental fruit moth is an important pest of peach and nectarine worldwide and of apples and pears in some production regions. Traps are used for monitoring, but the standard use of traps with sex pheromone lures is ineffective when orchards are treated with mating disruption. Traps baited with a combination of the sex pheromone of oriental fruit moth and codling moth in combination with a new trap design using a liquid bait was shown in collaborative studies in South America to improve seasonal monitoring of both moth sexes. Adoption of this new lure-trap design should allow growers to adopt action thresholds and reduce unnecessary use of insecticides.
9. Discovery that a common predatory bug in agriculture is actually a complex of multiple undescribed species. Effectiveness of predatory insects in controlling pest insects in orchards of the Pacific Northwest depends upon correct identification of those predatory insects. ARS scientists at the Yakima Agricultural Research Laboratory, Washington, collected and examined a species of predatory insect known to be an important source of biological control of mite and aphid pests in orchards. Scientists collected these insects from sites throughout the western United States, and found using a combination of morphological, behavioral, and genetic tools that what was assumed to be a single species is actually a complex of at least five currently undescribed species. These results show that the community of predatory insects providing biological control of insect pests in the Pacific Northwest is actually more diverse than originally assumed.
Yee, W.L., Cha, D.H., Linn, Jr, C.E., Klaus, M.W., Goughnour, R.B., Feder, J.L. 2012. Abundances of apple maggot, Rhagoletis pomonella, across different areas in central Washington, with special reference to black-fruited hawthorns. Journal of Insect Science. http://www.insectscience.org/12.124/i536-2442-12-124.pdf.