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United States Department of Agriculture

Agricultural Research Service

Research Project: Biorational Management of Insect Pests of Temperate Tree Fruits

Location: Temperate Tree Fruit and Vegetable Research

2011 Annual Report

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, formulations of codling moth granulovirus, and formulations of entomopathogenic nematodes will be designed and evaluated as a means to manage codling moth. Replacing 5352-22000-019-00D (October 2010)

3. Progress Report
Progress was made on all six objectives. For Objective 1 we determined that codling moth antennae are most sensitive to 4 chemicals from Gala apples, showed that antennal responses to apple volatiles were similar for wild and lab-reared moths, and improved methods for identifying insects consumed by predators. For Objective 2, we determined the histology of leafrollers infected by a virus, and demonstrated virus movement between moths and between moths and their eggs. This work shows potential for an “attract and infect” strategy to control leafrollers with virus. We tested a killing station baited with pheromone plus kairomone in small plots and showed 75% reduction in codling moths in monitoring traps. Orchard treatment with pheromone and pear ester reduced mating of female codling moths in apple orchards over pheromone alone. For Objective 3, we field tested a blend of apple volatiles, chemicals from fermented molasses, and apple volatiles plus acetic acid as trap lures for codling moth. We field tested baits for spotted wing drosophila, showing synergy of vinegar and wine and the role of acetic acid and ethanol in attracting flies. An improved trap/lure was developed for oriental fruit moth. Known wasp attractants were tested against an invasive paper wasp, but without positive results. Four commercial traps were compared for capturing apple maggot flies, with one trap shown to be superior. For Objective 4, we determined seasonal patterns of abundance of predatory insects in orchards to identify predators to be considered high priority for conservation management. Biochemical methods marked predatory insects to document their movement from orchard ground cover up into pear trees and predator feeding on pear psylla. Mortality of spiders treated with insecticides was determined, identifying several pesticides that are considered to be “soft” but showed high toxicity. For Objective 5, we determined that nearly no codling moth larvae (0.025%) survived cold treatment and photoperiod simulating conditions for apples exported to Taiwan. This information aids pest risk models and relates to exportation of apples from the U.S. Combination heat, low oxygen, and high carbon dioxide treatments were developed for use to disinfest fruit of peach fruit moth, oblique banded leafroller, grain chinch bug, and banded fruit weevil. We examined the efficacy of the brown sugar water flotation method versus a hot water method and detected 95% of cherry fruit fly larvae in cherries with the former method. Several pesticides were evaluated against cherry fruit fly, in order to reduce fruit fly larvae in harvested and packed cherries. For Objective 6, we generated > 3000 protein encoding gene transcripts for codling moth and identified genes encoding chemosensory binding proteins which are potential targets for disrupting codling moth reproduction. Similar genes were identified for light brown apple moth and navel orangeworm, among other insect pests.

4. Accomplishments
1. Bait for detection and monitoring spotted wing drosophila. The spotted wing drosophila is a new invasive pest of soft fruits in the U.S. that is a serious threat to growers of berries and cherries in the Pacific Northwest. Traps are used to detect its presence and determine the need for pest control measures. ARS scientists in Wapato, WA, developed and demonstrated an improved bait formulation that is a combination of vinegar and wine as a trap lure for spotted wing drosophila. This information improves the power of traps that are used to determine the presence of the fly and to determine the need to control it in fields and orchards. The results also indicate that chemicals in addition to acetic acid and ethanol might be isolated and identified from vinegar and wine to make a synthetic chemical lure for a dry trap or bait station.

2. Seasonal occurrence of predatory insects in orchards. Effectiveness of predatory insects in controlling early-season pests such as aphids in apple orchards of central Washington State is highly inconsistent. The numbers of aphid-feeding predators were monitored by ARS scientists in Wapato, WA, throughout the summer in 10 apple orchards of central Washington. Scientists found that known aphid-feeding predators colonized orchards too late in the growing season to provide the early-season control necessary to prevent outbreaks later in summer. These results indicate that methods other than natural colonization of orchards for aphid control, such as release of predatory insects, might be necessary to achieve consistent biological control of aphids in orchards.

3. Effects of combination heat and controlled atmosphere treatments on oblique banded leafroller. The oblique banded leafroller is a pest of quarantine concern in stone fruits in the Pacific West. In an effort to promote exports of organically produced tree fruits and reduce ozone depleting emissions of methyl bromide, the potential of using short term high temperatures in combination with controlled atmospheres was investigated as a means to control this pest in harvested fruit. All the immature stages of the oblique banded leafroller were less tolerant to the combination heat and controlled atmosphere treatments than codling moth and oriental fruit moth, when using an automated system which simulated such treatments of infested apples and peaches. The most tolerant stage was determined to be the 5th instar. This information will be used to develop and test non-chemical postharvest quarantine treatments against oblique banded leafroller in deciduous tree fruits.

4. Effects of combination heat and controlled atmosphere treatments on peach moth in apples. The peach fruit moth, Carposina sasakii is a serious insect pest of apples and peaches in South Korea. In an effort to reduce ozone depleting emissions of methyl bromide, which is currently used to kill this pest in fruit to meet export restrictions, the potential of using short term high temperatures in combination with controlled atmospheres to control this pest was tested. The last instar of the larval stage was the most tolerant to the combination treatment and this stage was less tolerant than the most tolerant stages of codling moth and oriental fruit moth, for which treatments already exist. Apple quality using this combination treatment was within acceptable market standards. These results support the utility of combination heat and controlled atmosphere treatments of apples to control peach tree moth.

5. Heated controlled atmosphere postharvest treatments for fruit pests. Non-chemical, environmentally-friendly quarantine treatments are preferred for use in postharvest control of insect pests. Combined high temperature and controlled atmosphere quarantine treatments were tested against the phytosanitary fruit pests, Macchiademus diplopterus (Hemiptera: Lygaeidae) and Phlyctinus callosus (Coleoptera: Curculionidae) for postharvest control. ARS scientists at Wapato, WA, found that treatment of both species was more effective under heating rates when the controlled atmosphere condition was applied. Under these conditions of controlled atmospheres, mortality of P. callosus was greater when a faster heating rate was used, but the opposite was true for M. diplopterus. This could be due to the physiological condition of aestivation contributing to metabolic arrest in response to the stresses being applied during treatment. Results indicate that the potential for the development of CATTS treatments for these phytosanitary pests, particularly P. callosus, is promising.

6. Identification of stress response proteins in codling moth. Codling moth, a pest of apple and pear, can have or develop tolerance to management treatments such as heat or even chemicals treatments by induction of proteins that aide their survival. ARS scientists at Wapato, WA, identified and characterized three stress response proteins from codling moth. These proteins were induced by codling moth exposure to excessive heat. The characterization of stress response proteins provides basic information and a better understanding of how insects survive extreme environmental conditions as well as disinfestations treatments and may permit the design of improved management and quarantine treatments.

7. Improved mating disruption with combined pheromone and kairomone. Codling moth is often managed in apples with mating disruption treatments, using the sex pheromone. However, the treatment is not completely effective in preventing mating of female moths in orchards. ARS scientists at Wapato, WA, found that treating orchards with the combination of that pheromone and a plant chemical called pear ester was more effective in preventing and reducing the mating of female moths. Such an improvement could provide either a more effective means to reduce fruit damage by codling moth, or a means to reduce the costs of codling moth control by mating disruption.

8. Identification of pheromone receptors in moths. Semiochemicals are used for monitoring and controlling numerous moth pests, including the codling moth in apple and pear orchards. Understanding the biochemical basis of detection of these chemicals provides avenues of research to discover and develop novel analogs disruptants, attractants, and masking agents. A technique was developed by ARS scientists at Wapato, WA, to identify odorant receptors expressed by codling moths, and the technique was then used to identify many odorant receptors in a variety of other moth pests of agricultural crops. This technique is much faster and less expensive than previous efforts and facilitates efforts to develop assays for identifying the corresponding ligands that might be useful in pest management.

Review Publications
Landolt, P.J., Adams, T., Rogg, H. 2011. Trapping spotted wing drosophila, Drosophila suzukii (Matsumura)(Diptera: Drosophilidae) with combinations of vinegar and wine, and acetic acid and ethanol. Journal of Applied Entomology. 136(2012):148-154.

Last Modified: 06/22/2017
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