Translocation of Aminopyralid from Straw Mulch to Plants in Perennial Strawberry Plantations: Case Study

Abstract

Aminopyralid (AP)-contaminated straw mulch is frequently used in strawberry production to maintain moisture and reduce weed growth. AP may be translocated by rain and irrigation. Contamination of plant tissues with AP during the production cycle at a strawberry farm was measured by HPLC MS/MS using a newly validated extraction method. Samples were removed from a commercial plantation using straw mulch. The highest AP levels (1.2–1.3 ng.g−1) were found in strawberries; the levels in leaves and roots were two and four to ten times lower, respectively. The amounts detected in fruits were 10 times lower than the dietary tolerances given by the U.S. Environmental Protection Agency for wheat grain and cattle milk/meat. The effect of AP on flowering and fruiting was investigated in pot experiments closely mimicking farm conditions. The released AP negatively affected flowering and reduced the total fruit weight two times. The study showed a significant release of AP from mulch straw during commercial strawberry production and documented the risk of using herbicide-contaminated straw for mulching.