Chemical Control of Longidorus elongatus on Peppermint with Nonvolatile Nematicides. J. N. Pinkerton, Research Assistant in Nematology, Department of Botany and Plant Pathology, Oregon State University, Corvallis 97331. H. J. Jensen, Nematologist, Department of Botany and Plant Pathology, Oregon State University, Corvallis 97331. Plant Dis. 67:201-203. Accepted for publication 11 June 1982. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-201.

The mint nematode Longidorus elongatus causes a serious yield decline in peppermint fields in floodplains of western Oregon. Experiments with foliar sprays of oxamyl and later with granular incorporation of aldicarb and oxamyl in soil resulted in significantly increased yields of hay and oil the first year after treatment. Timing of application was of primary importance, with November and/or March applications resulting in the greatest yield response. The most effective treatments were two broadcast sprays or one granular incorporation of oxamyl. Nematode populations were only slightly and temporarily reduced but did not correlate with yield response. Although root protection by oxamyl is brief, previously damaged plants were able to reestablish vigorous root systems and resume normal growth.

Keyword(s): Mentha piperita, nematode populations.