D3202: Postharvest management of the blueberry maggot, Rhagoletis mendax

Postharvest management of pests using fumigation or X-ray irradiation of fruits can facilitate international trade by ensuring quarantine insect pests are controlled. International trade in blueberries continues to increase, so we are exploring alternative approaches to the current standard methyl bromide treatments for preventing fruit infestation by insect pests. Our previous studies showed that fumigation by high doses of sulfur dioxide (SO2) to control the blueberry maggot, Rhagoletis mendax, caused bleaching and discoloration of blueberries. To achieve effective management of the pest while maintaining blueberry quality, we tested a protocol using a low dose (500 ppm) of SO2 for 2d exposure in this study and we also evaluated a phosphine (PH3) protocol over 3 days. Our results show that R. mendax can be controlled completely by 500ppm fumigation with SO2 for 2d, and by 300ppm fumigation by PH3 for 3d. Evaluation of irradiation treatments indicated that a 200Gy dose of X-rays controlled both R. mendax and the co-occurring Drosophila melanogaster (SWD) without damaging the fruit. We discuss the potential for SO2 and PH3 fumigation and X-ray irradiation within a systems approach for preventing R. mendax and D. suzukii infestation.