Dr. Zhangjing Chen receives USDA APHIS grant to study phytosanitation treatment of imported fruit to control exotic fruit fly spread and protect domestic growers

Congrats to Dr. Zhangjing Chen for being awarded a new grant from USDA APHIS! In 2016, 51% of the fruit consumed in the US was imported. The value of US fruit imports in 2019 was $16.4 billion. Of this, the estimated annual market value of the commodities that could host exotic fruit flies was $7.2 billion. In response to this insect threat to the domestic industry, the USDA has implemented a National Strategy to control the spread of the Mediterranean fruit fly (Magfly). Part of this strategy is to identify sustainable, efficient quarantine treatments for imported fruit. While heat treatment is known to be effective, the energy costs are high and temperature control, which is critical to preventing fruit spoilage, is difficult to maintain.

Scientists at the USDA APHIS Science and Technology laboratory in Miami, Florida, became aware of the work Dr. Chen and fellow researcher, Dr. Mark White, were conducting to develop a non-chemical, pre-shipment, phytosanitary treatment method for logs and pallets using vacuum and steam. Last year, and more recently this spring, scientists from the Miami lab came to Virginia Tech to conduct preliminary heat treatment tests on various fruit samples, using the vacuum/steam chamber at Virginia Tech. The results of these preliminary tests were encouraging.

This led to Dr. Chen being awarded a grant for researching the “Phytosanitary Treatment of Fruit Using Steam in a Chamber Under Vacuum.” This grant was funded by USDA APHIS. It seems the process of using vacuum and steam can help to precisely maintain the chamber temperature at 47C, which is the temperature to which the fruit is exposed, heating the fruit to the pit or core very quickly. Maintaining such an exact temperature is critical to killing the life stages of the fruit fly while not “cooking” the fruit. The precision and speed of this heat treatment process shows great potential to become part of the USDA Magfly control strategy.