Published online by Cambridge University Press: 20 January 2017
Wild chervil is an invasive biennial or short-lived perennial weed introduced into North America that negatively impacts forage production and degrades habitat for native plant species. A 2-yr study using prebloom mowing followed by combinations of herbicide, tillage, and grass seeding was conducted in the Pacific Northwest to identify an effective integrated weed management strategy for this species. By 2 mo after herbicide treatment (MAHT), wild chervil control with glyphosate + ammonium sulfate (AMS) and clopyralid was 83 and 73%, respectively. Tillage with or without herbicide pretreatment resulted in 92 to 98% wild chervil control at 2 MAHT, whereas herbicide without tillage gave only 45% control across all treatments. Tillage with or without subsequent grass seeding reduced wild chervil density four-fold compared to herbicide alone at 9 MAHT. Herbicide + tillage + grass seeding resulted in similar wild chervil cover (1 to 5% cover) as herbicide + tillage (1 to 6% cover) without subsequent grass seeding. Wild chervil biomass at 1 yr after herbicide treatment (YAHT) was reduced to 487 kg ha−1 (439 lb ac−1) with herbicide + tillage compared to 4,256 kg ha−1 for herbicide treatment alone. Herbicide + tillage + grass seeding increased grass dry weight at 1 YAHT from 201 kg ha−1 for herbicide + tillage to 1,575 kg ha−1, compared to 351 kg ha−1 in herbicide-only plots.