Page Banner

United States Department of Agriculture

Agricultural Research Service

Research Project: ECOLOGY, GENOMICS, AND MANAGEMENT OF STORED PRODUCT INSECTS

Location: Stored Product Insect Research Unit

Title: The case for a generic phytosanitary irradiation dose of 250 Gy for Lepidoptera eggs and larvae

Authors
item Hallman, Guy
item Arthur, Valter -
item Blackburn, Carl -
item Parker, Andrew -

Submitted to: Journal of Radiation Physics and Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 29, 2013
Publication Date: N/A

Interpretive Summary: Ionizing radiation is being used increasingly as a phytosanitary treatment to overcome biological barriers to trade in agricultural products. Generic treatments (one dose is used for a group of commodities and/or quarantine pests) allow for broader application. A generic dose of 250 Gy is proposed for all eggs and larvae of the insect Order Lepidoptera, a key group of quarantine pests. The measure of efficacy of this treatment is prevention of emergence of normal-looking adults when the most radiotolerant stage, late larva, is irradiated. This dose is supported by many studies comprising 29 species in 10 lepidopteran families, including some of the most important families and species of quarantine importance. Two of the studies found that doses >250 Gy were necessary, but they are contradicted by other studies with the same species showing that <250 Gy is adequate. In comparison a dose of 150 Gy for Tephritidae (fruit flies) was accepted by APHIS and the International Plant Protection Convention when only 14 species were studied and a number of studies did not support that low of a dose. A dose of 250 Gy for all Lepidoptera eggs and larvae gives a liberal margin of error that no insects in the group will survive the treatment.

Technical Abstract: A generic phytosanitary irradiation dose of 250 Gy is proposed for all eggs and larvae of the insect Order Lepidoptera, which contains many quarantine pests that inhibit trade in fresh agricultural commodities (e.g., fruits and vegetables). The measure of efficacy of this treatment is the same as that accepted for tephritid fruit flies: prevention of emergence of normal-looking adults. This dose is supported by many studies comprising 30 species in 10 lepidopteran families, including some of the most important families and species of quarantine importance. Two studies with two different species found that doses >250 Gy were necessary, but both of these are contradicted by other studies showing that <250 Gy is adequate. In comparison a dose of 150 Gy for Tephritidae was accepted by plant protection organizations when only 14 species were studied and a number of studies did not support that dose. A dose of 250 Gy for all Lepidoptera eggs and larvae leaves a liberal margin of error that no insects in the Order will survive the treatment.

Last Modified: 9/20/2014
Footer Content Back to Top of Page