Developing integrated pest management strategies for California mint

In California, mint production occurs in the northeast counties of Shasta, Lassen, Modoc, and Siskiyou. For optimum yield, mint requires long warm days and cool nights and until the mid 1990s, production has occurred primarily in the states of Idaho, Oregon, and Washington. Spider mites, Tetranychus urticae Koch, and a recently introduced Lepidoptera pest, mint root borer, Fumibotys fumalis Hodges, commonly attack mint and have a considerable negative impact on oil yield and quality. These pests pose significant management challenges and are the target of considerable pesticide use. The miticide, Omite and Lorsban (chlorpyrifos), are under regulatory scrutiny and used extensively against spider mites and mint root borer. The watersheds and environment of the Intermountain area, including the Fall River Valley and Klamath Basin, are extremely sensitive and the use of such insecticides is problematic. High quality, innovative research on mint pest management has been conducted in the Pacific Northwest; however such research is lacking in California. The objective of our study is to 1) Investigate and validate the spider mite management methods developed in the Pacific Northwest for California conditions, 2) Study the use of releases of predatory mites for spider mite management in mint in California, 3) Investigate the seasonal life history of mint root borer in California and the applicability of the population model developed by the Pacific Northwest to California conditions, and 4) Study the effectiveness of reduced risk insecticides for management of mint root borer in California. First year results will be discussed.