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.
3. Progress Report:
Olive fruit fly was found in olives along the eastern edge of California’s central valley near orchards where canning olives are grown. Psyttalia humilis, a parasitoid imported from Guatemala was 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 yellow pan trap is under evaluation as an attract-and-kill method for olive fruit fly control. Research is continuing on evaluating current sanitation practices in almonds and pistachios in order to determine the best use for entomopathogenic nematodes. They are economical only when applied through a microsprinkler irrigation system, which eliminates certain California growing areas. There is currently little interest in postharvest sanitation in pistachios, although that may change when insect pressure increases. Entomopathogenic nematodes will be an addition to current sanitation practices rather than a replacement. These activities meet the project objective of developing biologically-based management programs using biological agents and cultural controls. Mating disruption for navel orangeworm suppressed males captured in pheromone traps over 1,000 meters from the treatment site, whereas suppression of eggs in egg traps dropped off 100 meters from the treated area. Trapping efficiency of navel orangeworm males in commercially available red and white traps showed that more males were trapped in red traps, especially prior to leaf flush in pistachio orchards. Further trapping tests with traps of various light reflectance indicated flat black traps captured the fewest navel orangeworm males, whereas more were captured in shiny black and white and more still in aluminum foil-covered traps. Three years of navel orangeworm trap saturation experiments were completed – this reduction of trap capture efficiency is not linear. These activities meet the project objective of developing a sex pheromone based program for use in the integrated management of navel orangeworm. A high temperature/carbon dioxide treatment to disinfest walnuts of diapausing codling moth was shown to have promise as a rapid treatment for organic walnuts. The codling moth life stage most tolerant to low pressure/cold treatments was identified. The effect of bean moisture on mortality response of cowpea weevil to heat is being investigated. Cold tolerance of adult spotted wing drosophila after treatment with sulfur dioxide was determined. At doses used by industry to reduce mold growth, sulfur dioxide had little effect on adult survival. Although adult spotted wing drosophila were relatively cold tolerant, most test insects were dead after 6-8 days at 33°C, with little or no reproduction. Navel orange aroma volatile content were shown to be useful as a marker with which to develop heat treatment protocols that are effective as quarantine treatments but do not cause a loss in flavor quality. These activities meet the project objective of developing alternative physical treatments for dried fruits, nuts, and fresh fruits.
Obenland, D.M., Collin, S., Sievert, J., Arpaia, M. 2012. Impact of High Temperature Forced Air Heating of Navel Oranges on Quality Attributes, Sensory Parameters, and Flavor Volatiles. HortScience. 47:386-390.