1a. Objectives (from AD-416):
Objective 1: Determine the comparative efficacy of alternative chemicals to methyl bromide and develop methods that keep alternative fumigants as well as methyl bromide out of the atmosphere following postharvest fumigation. • Sub-objective 1.A. Determine efficacy, practicality, and product quality (phytotoxicity) of alternative fumigants such as phosphine, sulfuryl fluoride, propylene oxide, ozone, and others to control postharvest commodity pests. • Sub-objective 1.B. Determine the efficacy of sulfuryl fluoride as an alternative to methyl bromide for use in flour/rice mills by direct comparison in laboratory and field experiments. • Sub-objective 1.C. Test absorbent materials to find more efficient materials than coconut-based activated carbon to recapture methyl bromide and other fumigants. • Sub-objective 1.D. Develop stacking and airflow techniques to maximize the efficiency of capturing methyl bromide from airstreams following commodity fumigation. Objective 2: Electrophysiological and behavioral responses of pests to host compounds • Sub-objective 2.A. Cigarette beetle host attractant identification and behavioral evaluation. • Sub-objective 2.B. Navel Orangeworm host attractant identification and behavioral evaluation. Objective 3: Develop combination quarantine treatments for foreign and domestic hay exports including timothy, alfalfa, oat, Bermuda, and Sudan grass hays and rye straw that utilize hay harvesting and postharvest handling procedures, and apply chemical fumigants to minimize human exposure. Objective 4: Develop models to accurately predict damage to nuts by navel orangeworm and determine the feasibility, accuracy, and precision of these predictions. • Sub-objective 4.A. Develop models for damage in Nonpareil and pollenizer almonds in Kern County based on previous year’s damage, harvest date and/or sanitation efficacy and then determine if these models can be extended to the entire almond belt • Sub-objective 4.B. Determine if the methodologies or models developed for almonds can be used to predict navel orangeworm damage in pistachios • Sub-objective 4.C. Develop models for almonds relating navel orangeworm damage to males captured in pheromone traps within the same year
1b. Approach (from AD-416):
Develop alternative chemical controls and quarantine fumigations for stored product insects. Develop equipment and investigate the feasibility of controlling fumigant emission to the atmosphere by trapping and destruction. Develop combinations of fumigants with other technologies to reduce the dosage of fumigant required to control or eradicate stored product and quarantine insects in durable and perishable commodities. Develop non-chemical control approaches for stored product pests of commodities to reduce the use of methyl bromide. Develop methods to detect infestations by detecting volatile emissions from insects and/or commodity. Develop methods to enhance or maintain quality of perishable commodities and ensure that treatments developed do not reduce quality of persihable commodities or shorten shelf-life.
3. Progress Report:
A new volatile collection procedure has been calibrated and contrasted to published methods. Adapted from methods to collect purified samples for nuclear magnetic resonance (NMR) analyses, this method allows rapid determination of the release ratios of volatiles from synthetic pheromone sources. This straightforward method should be available to most biologists with modest assistance from a chemist. The two milestones concerning navel orangeworm damage in almonds and pistachios have been substantially met. In almonds, insect damage is also dependent on nut vulnerability; this was not addressed in the milestone. In pistachios, nut vulnerability factors were identified that were as important as harvest date. These new factors indicate orchard management influences susceptibility of pistachios to navel orangeworm. New studies have begun to determine if improved insecticide timing in almonds and pistachios can reduce damage. A large-scale, commercial confirmatory test to control Hessian fly puparia in compressed bales to timothy hay fumigated for 3-days with aluminum phosphide, was conducted in Ellensburg, WA. The commercial test resulted in 100% mortality of greater than 45,000 insects in partial fulfillment of Japan MAFF requirements for a certified quarantine treatment for hay imports. A study of navel orangeworm abundance and phenology in walnuts found high numbers of navel orangeworm adults and eggs in orchards in Tulare, Kings, and Fresno counties. Abundance varied, and high numbers were trapped in blocks with both low and high lepidopteran damage in the previous season. These represent resident populations. Novel chemical and non-chemical techniques were developed to rapidly disinfest raw agricultural products, control storage pests in processed products, reduce reliance on fumigation as a stand-alone measure for postharvest disinfestations, and minimize the environmental and ecological impact of postharvest processing. Coating type and concentration was identified as an important factor in mitigating phosphine fumigation damage to nectarines.
1. Development of quarantine strategies to control hessian fly in exported hay. Hessian fly is a pest of regulatory concern in the western states and new methods are needed to ensure trade partners that the insect is not accidentally introduced through hay imports. A large-scale commercial test resulted in complete mortality of greater than 45,000 puparia, and confirmed the efficacy of bale compression and a 3-day fumigation to control Hessian fly in hay exports to Japan. Completion of the evaluation phase of the project will result in a new certified quarantine treatment. This treatment will expedite shipments of high quality U.S. hay exports to Japan and help alleviate feed shortages.
2. Postharvest treatment of quarantine insect pests. Spotted wing drosophila (SWD), oriental fruit fly (OFF), and peach twig borer (PTB) are quarantine pests that threaten domestic transportation and/or international trade of specialty crops. ARS researchers in Parlier, California developed and applied novel systems-based approaches and methyl bromide fumigation treatments to control these insect pests in postharvest situations. The research to control SWD, OFF, and PTB was used to support critical USDA negotiations with foreign governments regarding phytosanitary issues. This work helped lead to the preservation of trade with Australia worth an estimated value of $150 million annually.
3. Postharvest methyl bromide alternatives research. Methyl bromide is extensively used as a fumigant for quarantine disinfestation but its use is increasingly restricted by legislative action. Experiments conducted by researchers in Parlier, California, demonstrated the insecticidal efficacy of sulfuryl fluoride and phosphine dispensed by a Horn generator. These fumigants appear to be the primary alternatives to methyl bromide for postharvest disinfestations of perishable and durable commodities, toward pest species endemic to California. This research on economically, and environmentally sound postharvest replacements for methyl bromide is the basis for technical interaction between industry, USEPA, and the UN's MBTOC, and TEAP committees and supports the US government’s compliance with international regulation under the Montreal Protocol.