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
Olive fruit fly was found in olives along the eastern edge of the California Central Valley near orchards where olives are grown for canning. A parasitoid, Psyttalia humilis, was imported from Guatemala and released in these locations and shown to successfully reproduce in olive fruit fly larvae. Pre-flight adults and crawling larvae of olive fruit fly were shown to travel long distances on the ground and could disperse in this manner throughout olive orchards. A corrugated yellow pan trap was evaluated as attract-and-kill method for olive fruit fly control. These activities meet the project objective of developing biologically-based management programs using biological agents and cultural controls. Navel orangeworm is the primary pest of almonds and pistachios in California. Evaluation of infestation levels in preharvest almond samples from orchards using mating disruption as a pest management technique provided valuable information about variation in almond development. Laboratory data showed little difference in the effect of delayed mating on navel orangeworm fertility, while field data showed that mating disruption had a substantial impact on navel orangeworm under spring conditions. Researchers adapted two methods to assess pheromone component release ratios from moths and lure formulations. Chemical cleaning of lure matrices and the addition of stabilizers that slow pheromone degradation led to a formulation that trapped as many moths as female-baited traps for one week. Field experiments show that a decrease in trap efficiency begins when about 50 males have accumulated in a trap. The role of orchard sanitation in reducing overwintering populations of navel orangeworm in almonds and pistachios was evaulated. Studies continued on the development rate and survival of navel orangeworm in pistachios, in order to understand differential mortality and development of this pest on almonds and pistachios. This information will be used to predict peaks in flight activity and improve management. These activities meet the project objective of developing a sex pheromone based program for use in the integrated management of navel orangeworm. Research to develop non-chemical disinfestation treatments focused on cold storage for spotted wing drosophila on grapes, radio frequency treatments for cowpea weevil in dried pulses, and low temperature vacuum treatments for codling moth in fresh fruits. Maturity of peaches at harvest was found to influence the amount of ethylene the fruit produced after heat treatment. This may alter the impact of heat treatment on peach flavor. Heating of navel oranges during quarantine treatment caused an accumulation of compounds with a fruity aroma that negatively impacted flavor. Production of these compounds was greatest in the final 30 minutes of the treatment. These activities meet the project objective of developing alternative physical treatments for dried fruits, nuts, and fresh fruits. The above research addresses National Program objectives by reducing postharvest use of methyl bromide for perishable and durable commodities, and protecting postharvest commodities from pests through ecologically sound means.
1. Control of Indianmeal moth with mating disruption. The Indianmeal moth is globally the most important stored product moth pest. Mating disruption is safer and less disruptive of work than fumigants and aerosol sprays, but is less widely used for control of Indianmeal moth. ARS scientists in Parlier, California, along with collaborators from the University of Michigan, demonstrated that mating disruption controlled Indianmeal moth infestation in dried beans in central California. This demonstration of successful control of the Indianmeal moth will encourage adaption of mating disruption, thereby protecting food in distribution channels while reducing use of insecticides and improving worker safety.
2. Impact of high temperature forced air heating of navel oranges on flavor quality. Heat is an effective quarantine treatment but can sometimes cause off-flavor in oranges. ARS researchers from Parlier, California, in collaboration with researchers from the University of California, Kearney Agricultral Center, found that heat caused a significant loss in flavor but that this change in flavor did not occur until the final 30 minutes of treatment. The off-flavor was associated with an increase in amount of flavor compounds with a fruity aroma. This research demonstrated the timing and likely cause of heat-induced flavor loss in citrus, thus providing potential ways to help eliminate this problem.
3. Development rate and survival of navel orangeworm on pistachio. The navel orangeworm is the primary pest of almonds and pistachios in California, two commodities grown on almost one million acres. An ARS scientist in Parlier, California, investigated the development of navel orangeworm on pistachios. It was assumed that navel orangeworm developed at the same rate on pistachios as on almonds, but the study found that this insect developed faster and had higher survival on pistachios. This finding has implications for improved control of this insect through improved understanding of its population dynamics.
4. Assessing the ability of navel orangeworm to detoxify chemicals. The navel orangeworm is the primary pest of pistachios and almonds in California, yet little is known about its origin. In collaboration with an ARS scientist in Parlier, California, molecular techniques were used by University of Illinois scientists to clone a cytochrome P450 monoxygenase enzyme of the navel orangeworm used to detoxify secondary plant compounds. This enzyme specifically breaks down imperatorin, a furanocoumarin used by plants to defend against insects, suggesting that this compound was in the original host of this insect. This knowledge should help determine the original host or host plants and will provide insight into predicting its ability to attack new crops, as well as improving control. The impact of improved control is damage reduction and decreased use of insecticides.
5. Biological and cultural control of olive fruit fly. Olive fruit fly is the key pest of canning olives and threatens new oil olive plantings in California. An ARS scientist from Parlier, California, conducted an annual biological control program for olive fruit fly in California with releases of an imported parasitic wasp in newly discovered Central Valley pest populations. The tiny wasp was found established on olive fruit fly in a coastal location. The work helps protect the California canned olive and oil industry valued at $75 million annually. Biological control of olive fruit fly using the imported wasp offers growers an alternative to expensive bait sprays to suppress the pest in California olive orchards.
Yokoyama, V.Y., Rendon, P.A., Wang, X., Opp, S.B., Johnson, M.W., Daane, K.M. 2011. Response of Psyttalia humilis (Hymenoptera: Braconidae) to olive fruit fly (Diptera: Tephritidae) and conditions in California olive orchards. Environmental Entomology. 40:315-323.