1a.Objectives (from AD-416):
Conduct basic and commercial tests to determine the effectiveness of PH3, PH3+CO2, and modern compressors to control Hessian fly in single or combined treatments, and the effect of postharvest hay handling practices on Hessian fly mortality in the laboratory and field.
1b.Approach (from AD-416):
Hessian fly will be reared in the greenhouse at the USDA, ARS, Parlier and Manhattan. Basic fumigation tests will be conducted in the facilities provided by the ARS in Parlier and the National Hay Association in California, Oregon, and Washington. Laboratory dose-response fumigation tests will determine the effect of temperature, exposure time, and PH3 or PH3+CO2 dosage on Hessian fly mortality, and establish a treatment schedule. Large-scale fumigation tests at hay handling facilities will confirm the efficacy of a proposed PH3 or PH3+CO2 fumigation schedule as a quarantine treatment. Bale compression tests at hay handling facilities will be used to determine the effect of compressors on mortality of Hessian fly puparia. Large-scale compression tests will be used to confirm the efficacy of bale compression alone or in combination with fumigation as a quarantine treatment. Basic tests will determine the effect of postharvest drying and bale curing on Hessian fly mortality. Data will be provided to The National Hay Association in support of market access for hay exports from the western U.S.
The agreement was established in support of the in-house project objective 3, to develop quarantine strategies to control Hessian fly in exported hay. A large-scale, commercial confirmatory test to control Hessian fly puparia was conducted. Three-tie compressed bales of timothy hay were fumigated for 3-days with 61 g/28.3 m³ aluminum phosphide followed by a 24 hr aeration. This test was conducted in Ellensburg, Washington, in partial fulfillment of Japan MAFF requirements for a certified quarantine treatment for hay exported to Japan. The preliminary results of this test are summarized as follows: 1. The test fulfilled the Japan MAFF requirement of 0 survivors in 30,000 insects tested. 2. Bale compression was 117 kg/cm² which is higher than previously achieved. 3. Temperatures maintained during the test allowed the fumigation to be certified at 20°C or higher. 4. Fumigant concentrations ranged from 345—861 ppm during the three-day test. 5. Copper detection plate corrosion after treatment provided visual verification of fumigation. 6. Fumigant residues were less than 0.01 ppb.