Start Date: Jan 01, 2012
End Date: Sep 30, 2012
This project takes advantages of our recent discovery of significantly enhanced toxicity of oxygenated phosphine fumigation and the availability of LBAM supply for large scale research. Our recent discovery of enhanced toxicity of oxygenated phosphine fumigation against insects and the preliminary results of complete control of LBAM eggs suggest it is feasible to control LBAM with oxygenated phosphine fumigation. LBAM is quarantined insect and can only be reared in quarantine facilities. This restriction makes LBAM research very difficult if not impossible in most research laboratories especially for research which requires large numbers of LBAM. The close proximity to APHIS LBAM rearing facility in Moss Landing, CA places us at a unique position of being able to carry out large scale fumigation research for LBAM control at ARS in Salinas, CA. The post-doctoral scholar under this proposal will participate in planning and carry-out oxygenated phosphine fumigation research to control LBAM on fresh vegetables and fruits, including lettuce, table grapes, strawberries, and stone fruits. Studies will be conducted to optimize oxygenated phosphine fumigations to control LBAM eggs, determine safety of oxygenated phosphine fumigation to postharvest quality of fresh products, and develop treatment protocols for commercial scale oxygenated phosphine fumigations. A diluted sample with cylinderized pure phosphine (Vaporphos) will be used. Oxygenated phosphine fumigation treatments will be determined for complete control of LBAM eggs. LBAM eggs will be fumigated in glass jars with different phosphine concentrations (500-2500 ppm) under various superatmospheric oxygen levels (30-80%) to determine effective treatments at different temperatures (1, 5, 10C), acceptable for storing different fresh commodities. Selected treatments will be tested on head lettuce, table grapes, and other vegetable and fruits. Commodities will be fumigated in small (1 cu) and large (442 liters) chambers to evaluate the potential impact on postharvest quality. Treated products will be stored for 2 to 4 weeks before being evaluated for postharvest quality. Pallet scale oxygenated phosphine fumigations will be conducted to verify efficacy and safety of the treatment for commercial adoption. A pallet load of lettuce will be fumigated in a sealed plastic bag together with LBAM eggs under a superatmospheric level of oxygen using an established method. Oxygen will be released into the bag and air in the bag will be evacuated with a vacuum pump, regulated by a light sensor-based control mechanism until the desired high oxygen level is established, monitored with an oxygen analyzer. Phosphine will then be released into the bag to start the fumigation treatment and phosphine level will be monitored with a phosphine monitor. After fumigation, survival of LBAM eggs will be assessed, and product quality will be evaluated after at least 2 weeks of post-treatment storage. Other commodities such as table grapes may also be tested in pallet scale trials.