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United States Department of Agriculture

Agricultural Research Service


Location: Commodity Protection and Quality Research

2013 Annual Report

1a. Objectives (from AD-416):
The overall objective is to develop practical and economical non-chemical insect control and disinfestation treatments that are safe and environmentally acceptable to replace methyl bromide for fresh and durable commodities. Objective 1: Develop a biologically-based management program using biological agents and cultural controls. • Sub-objective 1.A. Develop a biological control program for olive fruit fly using imported parasitoids • Sub-objective 1.B. Develop cultural control methods for olive fruit fly • Sub-objective 1.C. Develop a laboratory diet for olive fruit fly • Sub-objective 1.D. Improve control of navel orangeworm in orchards by using entomopathogenic nematodes that target over-wintering larvae • Sub-objective 1.E. Develop information for obtaining approval to release insect parasitoids into bulk-stored dried fruits and nuts. • Sub-objective 1.F. Determine the potential of commercially available or novel pathogens to control stored product Coleoptera. Objective 2: Develop a sex pheromone based program for use in the integrated management of navel orangeworm. • Sub-objective 2.A. Develop a stable formulation for the recently identified female sex pheromone • Sub-objective 2.B. Develop trapping data to calculate realistic navel orangeworm numbers based on standard sticky trap catch data. • Sub-objective 2.C. Determine the size of mating disruption treatment block necessary for reduction of navel orangeworm damage in almonds • Sub-objective 2.D. Determine fitness of females and potential impact of mating disruption at times of first and second flight. Objective 3: Develop alternative physical treatments for dried fruits, nuts, and fresh fruits • Sub-objective 3.A. Determine whether forced hot air combined with controlled atmospheres (CATTS) for stone fruit or forced hot air for oranges are viable quarantine treatments. • Sub-objective 3.B. Develop and field test low and high temperature treatments for dried fruit and nut insect pests. • Sub-objective 3.C. Develop and field test vacuum treatments using low cost, flexible storage containers for dried fruit and nut insect pests.

1b. Approach (from AD-416):
Postharvest insects cause significant economic loss to the agricultural sector, both through direct damage by feeding or product contamination, and by the cost of control programs. The export trade of certain horticultural products may be affected as well, with importing countries requiring quarantine treatments to prevent the introduction of exotic pests. Of particular concern to agriculture in the Western U.S. are field pests such as the olive fruit fly (Bactrocera oleae), navel orangeworm (Amyelois transitella), and codling moth (Cydia pomonella), and storage pests such as the Indianmeal moth (Plodia interpunctella). Processors rely largely on chemical fumigants such as methyl bromide for insect disinfestation, but regulatory, environmental and safety concerns mandate the development of non-chemical alternatives. In addition, with the elimination of methyl bromide as a fumigant because of its ozone depletion, the development of alternatives is an immediate concern. This project addresses this problem with a broad collaborative approach, examining both preharvest, biologically based control strategies as well as physical postharvest disinfestation treatments. Areas of investigation will include the development of biological and cultural control practices for olive fruit fly, improved field control of navel orangeworm with mating disruption and entomopathogenic nematodes, improved sex pheromone of navel orangeworm, new microbial controls for stored product beetles, commercial-scale forced hot air control atmosphere treatment for stone fruits, volatile markers to identify suitable hot forced air treatments for citrus, and radio frequency heating, low temperature storage, vacuum treatments, and parasitoid releases for control of postharvest dried fruit and nut insects. New, non-chemical methods for control of these economically important pests will be the outcome of this research. Formerly 5302-43000-031-00D (03/08).

3. Progress Report:
This is the final report for this project, which has been replaced by the new project 5302-43000-038-00D, "Non-Chemical Alternatives for Post-harvest Pests of Fresh Fruits, Dried Fruits, Tree Nuts, and Other Durable Commodities". Olive fruit fly was shown to be intolerant to hot summers, limiting its distribution in the state. An imported wasp was released in infested olive orchards for biological control. A pan trap was developed to attract and kill flies and shows promise as an economical field control device. Implementation of a combination of control tactics to suppress the pest supports cultivation of California olives. Entomopathogenic nematodes provided an effective control of overwintering navel orangeworm (NOW) in pistachio orchards. The parasitoid Habrobracon hebetor reduced insect fragment levels when released into almonds infested with overwintering Indianmeal moth. These activities address objective one. Nut susceptibility to infestation by NOW was found to be as important as harvest date in reducing damage. The importance of almond orchard sanitation in reducing insect damage was underscored. Management practices clearly influence the susceptibility of both almonds and pistachios to NOW. These field studies will be used to improve insecticide timing and application in almonds and pistachios, further reducing damage. The chemical sex pheromone of the NOW was determined and baits using this new pheromone blend were shown to capture male moths as effectively as female-baited traps. More male NOW were captured in red versus white traps. Trap saturation was found not to be an all or none phenomenon; in all of the trap types studied, trap efficiency declined after 30-50 males were captured and declined more rapidly as more males were trapped. Mating disruption for control of NOW in almonds has less impact on beneficial insects and humans compared to insecticides. Field samples showed a decrease of damage 200 feet from the edge of an orchard, and suggest treatment blocks of over 40 acres. This information will increase the use of mating disruption. These activities address objective 2. Vacuum treatments, radio frequency heat treatments, and treatments combining high temperature with high carbon dioxide were shown to have potential as alternatives to fumigants for disinfestation of tree nuts and dried legumes. The codling moth life stage most tolerant to low pressure/cold treatments was identified. The relative cold tolerance of spotted wing drosophila life stages was determined. A range of peach and nectarine varieties were subjected to 46C forced air heating and a controlled atmosphere of 1% oxygen and 15% carbon dioxide to evaluate the impact on fruit quality of this insect disinfestation treatment. As long as initial fruit quality was good the treatment could be successfully conducted using bulk fruit placed into lugs, but treatment of boxed fruit sometimes led to quality loss due to uneven heat distribution. These activities address objective three.

4. Accomplishments
1. Sampling range of navel orangeworm pheromone traps. The navel orangeworm is the principal insect pest of almonds and pistachios. Understanding the area from which monitoring traps attract males is important to effective trap use. An ARS researcher at Parlier, California, in collaboration with industry cooperators, showed that the range and direction from which males are drawn to pheromone traps for navel orangeworm is density dependent and, at low densities, is greater than 400 m. These findings will aid the use of pheromone traps for the protection of these export crops, worth >$3 billion per year.

2. Navel orangeworm sex pheromone elucidation and field implementation. Sex pheromones are chemical signals that bring male and female insects together for mating. An ARS researcher at Parlier, California, along with researchers from the University of California has identified the unusual chemical blend that comprises the female sex pheromone of the navel orangeworm. This insect is the primary pest of California almonds and pistachios, crops worth more than $4 billion annually. Industry partners have licensed this patented pheromone blend to produce trap lures whose sales value is expected to exceed $1.25 million per year. The lures will give nut growers the best tool available to monitor navel orangeworm and thereby improve control.

3. Navel orangeworm damage in almonds is correlated with previous year damage, harvest date, and sanitation efficacy. The navel orangeworm is the principal moth pest of almonds, the second most important commodity grown in California. An ARS researcher at Parlier, California, identified two management factors, harvest date and postharvest sanitation, as predictors of damage to almonds. One other factor, proximity to pistachios, was also important. An improved understanding of the relative importance of these factors will reduce insect damage, improve nut quality and further increase overseas export of almonds, thereby increasing profits and improving the US balance of trade.

4. Navel orangeworm damage in pistachios is correlated with harvest date. The navel orangeworm is the principal moth pest of pistachios, an important and increasingly valuable California export crop. An ARS researcher at Parlier, California, identified that time of shell split, natural shell damage, and fungal damage combined with harvest time were predictors of navel orangeworm damage. This research underscored the need to integrate insect and fungal control to reduce damage, which in turn will increase nut quality and boost exports. Improvements in nut quality will provide higher profits to growers and boost exports, reducing the trade deficit.

5. Biological and cultural control of olive fruit fly. Olive fruit fly is an invasive pest in California olives and threatens production of canned and oil olives by destroying fruit. An imported wasp released in previous years as a biological control was recently recovered in a coastal area and shown to seasonally reduce fly numbers by an ARS scientist at Parlier, California. A trap was also developed and tested in the greenhouse for attraction and kill of adult flies and shows promise as an economical field control device. By combining and implementing these two control tactics in a pest management program, crop loss due to this serious pest will be reduced, supporting California as the leading U.S. producer of table olives and olive oil.

6. Cold storage treatments for spotted wing drosophila in table grapes. Because spotted wing drosophila is a potentially serious pest of many small fruit crops, susceptible hosts must undergo a quarantine treatment before export to countries where the pest is not yet found. ARS scientists at Parlier, California, determined the life stage most tolerant to normal transit cold storage temperatures, and the approximate exposure times needed to obtain quarantine security. This information has been used to determine the potential of cold storage treatments as an alternative to chemical fumigants. Such a non-chemical quarantine treatment would help to reduce U.S. dependence on environmentally damaging fumigants while maintaining valuable foreign markets.

Review Publications
Burks, C.S., Higbee, B.S. 2013. Effect of abundance of the navel orangeworm on sampling range and interference between pheromone traps. Environmental Entomology. 42(1):143-149.

Yokoyama, V.Y. 2012. Mobility of olive fruit fly (Diptera: Tephritidae) late third instars and teneral adults in test arenas. Environmental Entomology. 41:1177-1183.

Jiao, S., Johnson, J.A., Mattinson, D., Fellman, J., Davenport, T., Wang, S. 2013. Tolerance of codling moth and apple quality associated with low-pressure/low-temperature treatments. Postharvest Biology and Technology. 85:136-140.

Last Modified: 06/24/2017
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