Submitted to: Proceedings Tri State Mint Convention
Publication Type: Proceedings
Publication Acceptance Date: 1/1/2004
Publication Date: 1/1/2004
Citation: BOYDSTON, R.A., BAKER, R. WEED RESEARCH IN MINT. PROCEEDINGS FOURTH ANNUAL TRI STATE MINT CONVENTION. p. 13-37. 2004.
Technical Abstract: Weeds reduce oil yield and quality of mint oil. Research was conducted to identify and evaluate new herbicides for use in mint crops; determine effects of field bindweed and MCPB on spearmint oil yield; determine comparative efficacy of flumioxazin and sulfentrazone when applied alone or in tank mixes with paraquat and two adjuvants; determine effect of postemergence applied herbicides used in peppermint on beneficial arthropods; and to determine salsify time of emergence and seed survivability in establishment in mint and response to herbicides applied at several growth stages. Fluroxypyr, flufenacet, cloransulam, bromoxynil+MCPA, mesotrione, sulfentrazone, flumioxazin, and clomazone were tested for selectivity on spearmint or peppermint in eight separate field trials. Fluroxypyr applied to dormant mint controlled several problem weeds without injury to mint and increased oil yield in peppermint compared to weedy checks. One spring application of MCPB suppressed field bindweed and increased oil yield of mint compared to nontreated checks. Paraquat greatly increased control of emerged winter annual weeds when applied with flumioxazin or sulfentrazone, whereas COC and nonionic surfactant had little effect on flumioxazin or sulfentrazone efficacy. Beneficial arthropod populations in native spearmint were not affected by currently registered mint herbicides or new non-registered herbicides. Salsify seed longevity, time of emergence, and growth and development were evaluated in peppermint. Most salsify emerged several weeks after planting and seed longevity in soil was minimal at six to twelve months. Four herbicides were evaluated for control of salsify when applied in various growth stages in greenhouse trials. Salsify was susceptible to several herbicides applied pre up to the 4-lf stage of growth. Three IR-4 residue studies were conducted with MCPB on mint and results sent to IR-4 headquarters to support the eventual EPA listing of a residue tolerance for MCPB in mint.