Natural products might provide an organic means of weed control. Our objective was to evaluate the potential use of vinegar and a clove-oil product with regard to how volume, concentration, and application timing affect weed control and crop response. Treatments included broadcast applications of 200- and 300-grain vinegar at 318 liters per hectare (L/ha), 150- and 200-grain vinegar at 636 L/ha, a 3.4% v/v clove oil mixture in water (318 L/ha), and a 1.7% clove oil mixture in 200-grain vinegar (318 L/ha). Field trials were conducted in sweet corn, onion, and potato. Weed control, weed biomass, crop injury, and yield data were collected. Corn treated at 15 and at 30 to 45 cm was initially burned and stunted by these products. By 4 wk after application much of the initial injury was outgrown. Late applications significantly reduced yields of early-maturing sweet corn ‘Trinity’. With the exception of the 200-grain vinegar (318 L/ha) treatment, early applications to sweet corn ‘Avalon’ did not reduce marketable yield. Two hundred-grain vinegar (636 L/ha) applied to pre-emergence–flag stage onion reduced the duration of the first handweeding by 59 to 67%. All treatments reduced onion yields when treated at the 2-leaf stage. Potato treated early (2 to 10 cm) and late (30 cm) were injured by all vinegar treatments 59 to 83%, 1 d after treatment (DAT). Potato yield losses were insignificant with applications of 3.4% clove oil and with some low-volume (318 L/ha) vinegar treatments. Product efficacy was dependent on the weed species and their size at the time of application. Weed control was greatest (83%, 1 DAT) with 200-grain vinegar (636 L/ha). Broadcast applications of vinegar and clove oil have potential for use on young, actively growing sweet corn, onion, and potato.
Nomenclature: Acetic acid; clove oil; Matran II; vinegar; corn, Zea mays L.; onion, Allium cepa L.; potato, Solanum tuberosum L