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United States Department of Agriculture

Agricultural Research Service


Location: Commodity Protection and Quality Research

2010 Annual Report

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. Formerly 5302-43000-030-00D and 5302-43000-028-00D (12/07)

3. Progress Report
Hay harvesting and drying conditions were shown to increase the mortality of Hessian fly puparia in incubator tests that simulated climates where export quality hay is grown in the western states. Field drying tests were conducted to confirm these observations. Basic tests showed that Hessian fly puparia is controlled with a phosphine and carbon dioxide gas mixture dispensed from cylinders at a minimum dose of 750 ppm, temperature of 20°C or higher, and duration of 4 days. Data were collected documenting the relationship between poor sanitation in Butte and Padre variety almonds and overwintering survival of navel orangeworm in Madera county. Industry pistachio harvest data were collected for the Central Valley (approximately 35% of the harvest) so that the correlation between a multitude of factors including nut maturity, shell integrity and navel orangeworm damage could be established. Field trials were conducted establishing the duration of protection and ovicidal activity of the insecticides Assail, Warrior, Intrepid, Altacor and Permethrin. Significant progress was made in relating the number of navel orangeworm captured in traps to subsequent damage in almonds. Work continued on pheromone lure development for the navel orangeworm, and analyses procedures of pheromone compounds have been refined. New handling protocols reduce decomposition of labile compounds and are also employed in isolation of host volatiles. Volatiles from nuts can now be analyzed and assessed in bioassays; ovipositional and antennal bioassays are in use to isolate host components employed by navel orangeworm to locate their hosts. Separately, field trapping of navel orangeworm in female-baited traps show that saturation effects appear logarithmic as more males are trapped. Validation of sulfuryl fluoride as a methyl bromide alternative is now focused on finding an ovicidal "partner" for scenarios where insect control is required < 24h of harvest. Work on high-concentration low-temperature "Horn" phosphine is promising; stone fruit, table grape, and citrus industries are transitioning toward commercial use in California. Low-emission chamber fumigation development has been limited due to a staffing void that will be resolved in FY2011. Invasive species research is ongoing via USDA-APHIS collaboration.

4. Accomplishments
1. Development of Quarantine Strategies to Control Hessian Fly in Exported Hay. US and foreign regulatory agencies seek new methods to ensure that Hessian fly is not accidentally introduced through hay shipped from the western states. ARS researchers in Parlier, California examined different methodologies to control this insect pest. Hay harvesting and drying practices increased mortality of Hessian fly puparia in warm and arid climates where export quality hay is grown. In addition, fumigation with a phosphine and carbon dioxide gas mixture completely controlled this pest in laboratory tests. This work supports the concept that the occurrence of Hessian fly in harvested, processed, and fumigated hay bales is negligible and protects a $660 million annual foreign market.

2. Development of a predictive model for navel orangeworm damage to Nonpareil Almonds. Navel orangeworm is the primary pest of California almonds. ARS scientists at the San Joaquin Valley Agricultural Sciences Center, Parlier, CA, and collaborators at Paramount Farming Company previously assessed the relative contribution of harvest date, previous year crop residue, and proximity to pistachios as contributors to its damage in Nonpareil almonds. These data were used to create a learning tool that is now hosted on the website of the Almond Board of California. This information will improve control of navel orangeworm and help reduce the rejection rate of exported almonds.

3. Identify risk factors for navel orangeworm damage in pistachios. The navel orangeworm is the primary pest of pistachios in California. There is substantial information available that can be used to determine both the pattern of damage and identify risk factors, yet this information has not been utilized. In 2007 - 2009 ARS scientists at the San Joaquin Valley Agricultural Science Center, Parlier CA and industry collaborators obtained gradesheets representing more than 65% of the entire harvest and determined the relationships between harvest date, shell integrity, and pistachio maturity. The information obtained will be used to improve control of this pest.

4. Identify factors that influence the success of insecticide application. The navel orangeworm is the primary pest of pistachios in California and it is controlled by multiple applications of insecticide. In order for new insecticides to be adopted by growers, information on their efficacy must be obtained. These efforts are complicated by the varying results caused by differences in application speed. Studies were initiated by ARS scientists at the San Joaquin Valley Agricultural Science Center, Parlier, CA and industry collaborators to quantify relationships between application speed and coverage. This will improve control of this pest.

5. Prediction of navel orangeworm damage to almonds using egg traps. Egg traps are currently used for timing insecticide application for navel orangeworm (NOW), but not for prediction of damage. ARS in Parlier, CA, compared eggs per trap with damage in Monterey almonds with a wide range of NOW damage. A significant association of high egg counts with subsequent damage was found, suggesting that threshold egg trap counts could be used as an early indication of risk of high damage. These findings will refine integrated management of NOW in almonds, thereby protecting California’s >$2 billion dollar almond industry while reducing insecticide use.

6. Residue remediation using ozone and ozone-ethylene fumigations. Export of California specialty crops is sometimes hampered by the presence of chemical residues that occur as a result of commonly-used agricultural practices. ARS researchers in Parlier, California evaluated different ways of eliminating these residues. Fumigation of fruit with ozone or a combination of ozone and ethylene was shown to reduce the residue concentration. This research resulted in a technique, which is applicable to numerous commodity types, for reducing residues to satisfy minimum residue level quotas that serve as trade barriers to California specialty crop export, estimated at $8 billion annually.

7. Identifying deficiencies of sulfuryl fluoride on insect eggs. Sulfuryl fluoride is an effective fumigant against larval and adult stages of insects but its effectiveness against the egg stage is unclear. ARS researchers in Parlier, California evaluated the effects of sulfuryl fluoride fumigation on postharvest insect eggs. The work demonstrated that sulfuryl fluoride performs poorly at killing the egg stage of target insects that exist in California. This work is the most comprehensive tool to date for indexing the potential utility of sulfuryl fluoride fumigations, relative to established methyl bromide protocols, for controlling insect pest infestations of stored dried fruit and nuts so that domestic and international distribution is maintained.

Review Publications
Kress, H., Park, J., Mejean, C.O., Forster, J.D., Park, J., Walse, S.S., Weiner, O.D., Fahmy, T.M., Dufresne, E.R. 2009. Cell stimulation with optically manipulated microsources. Nature Methods. 6:905-909.

Kemper, J., Walse, S.S., Mitch, W.A. 2010. Quarternary Amines as Nitrosamine Precursors: A Role for Consumer Products?. Environmental Science and Technology. 44(4):1224-1231.

Last Modified: 07/20/2017
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