“CATTS” Perfect for Zapping Apple Pests

Crunchy apples from orchards of the Pacific Northwest are eagerly sought by food buyers in the United States and abroad. But some foreign buyers require growers and packers to take special steps to ensure that the fruit exported from the United States is free of certain pests. Agricultural officials in South Korea, Japan, Taiwan, Canada and Mexico, for example, are concerned that codling moths or oriental fruit moths could escape from shipments and invade orchards.

Agricultural Research Service entomologist Lisa G. Neven is providing practical, affordable techniques that conventional and organic growers and packers can use to disinfest their premium fruits. Neven is based at the ARS Fruit and Vegetable Insect Research Unit in Wapato, Wash. She is doing these experiments with PacOrganic and King Blossom, two organic producer-packers in Washington state.

Neven's method, developed in ongoing experiments during the past nine years, is called “CATTS”-- short for Controlled Atmosphere Temperature Treatment System. CATTS relies on placing bins of fruit in chambers and then changing the temperature and composition of the atmosphere surrounding the fruit for a short period of time.

Her tests with apples showed that raising the temperature of the atmosphere about 18 degrees F per hour until the fruits’ internal temperature is 111 to 117 F, in a mix of 1 percent oxygen and 15 percent carbon dioxide, zaps any living codling moths or oriental fruit moths.

According to Neven, the regimen helps maintain apples’ quality longer. She did these tests on more than 138,000 pounds of Gala, Jonagold, Braeburn, Granny Smith, Fuji, and Golden and Red Delicious apples. Her work is based in part on discoveries made by scientists in Israel.

Conventional growers who today fumigate their fruit for export with methyl bromide are following Neven’s studies because of the escalating cost of the chemical.

ARS is the U.S. Department of Agriculture’s chief scientific research agency.