U.S. authorities have tightened import rules for plums from Chile following a recent pest detection, with the USDA's Animal and Plant Health Inspection Service (APHIS) now requiring an approved treatment for the fruit.

APHIS announced on Thursday that, effective immediately, it is modifying the import rules to prevent the entry or introduction of the harmful plant pest, European Grapevine Moth (EGVM), also known as Lobesia botrana.

Fresh Chilean plums have been allowed into the United States since 1933. Currently, most consignments are inspected at the port of export with APHIS oversight under a pre-clearance agreement between Chile and the United States. Consignments are treated with methyl bromide under preclearance in Chile if certain external pests are found.

The APHIS preclearance program in Chile intercepted an EGVM pupa Feb. 17, 2021 and an EGVM larva on Feb. 23, 2021. Both interceptions were from plums produced in General O’Higgins region of Chile for export to the U.S., the organization said in a statement.

APHIS said it has determined that fresh plum consignments destined for the U.S. from Chile pose a "significant phytosanitary risk" to the domestic fruit industry, especially grapes, due to EGVM in Chile’s fruit production areas.

"Because of the recent detections of EGVM on Chilean plums, APHIS now considers fresh plum fruit to be a host of EGVM," APHIS said.

"To mitigate the risk of EGVM, all consignments of plums from Chile for export to the United States must be treated with an APHIS approved treatment."

"Current treatment options include irradiation with a minimum absorbed dose of 400 Gy upon arrival in the United States or fumigation with methyl bromide in accordance with APHIS treatment regulations found at 7 CFR parts 305, in Chile under the preclearance program."

Fumigation can be conducted in Chile under an APHIS preclearance program until the end of the shipping season for plums from Chile, and no later than May 31, 2021.

The European Grapevine moth is native to Europe and attacks primarily grape flowers and fruit but has several other hosts of poor or unknown status. In Europe it causes grape growers to incur control costs and significant damage.

The European Grapevine Moth was detected in Chile in April of 2008 on grapes, APHIS said.

Damage caused by the pest can be extensive, with some Chilean growers having reported losses of up to 70% of their grape crops in 2008, it said. EGVM became established in California in 2009 and was eradicated after seven years and expenditures of more than $100 million.