Wild cucumber is a perennial vine that regrows each year from an enormous root. The plant spreads by seed, not by root fragments. The harmful effect of wild cucumber is mostly a result of the top growth that crowds, shades, and deforms the crops. Any type of physical control has temporary results because of the food storage in the root. This food reserve also means that if herbicides are to be effective, they must move to the root and block production of new shoots. Any control plan should call for treatment for several years. Recommendations that follow are based on limited research at Oregon State University.
dicamba (Clarity, Rifle)
Rate 1 to 2 lb ae/A or 1% concentration for application with a handgun sprayer.
Time Apply when cucumber is growing rapidly in late spring or early summer.
Remarks Expect 80 to 100% control 1 year after treatment.
Caution Dicamba seriously reduces seed production of grasses or grain crops if applied at the wrong growth stage. Do not use 2-lb rate on large areas if a crop is growing in the field.
Site of action Group 4: synthetic auxin
Chemical family Benzoic acid
glyphosate
Rate 1.5 lb ae/A or 0.5 to 1% solution for application with a handgun sprayer.
Time Apply when the cucumber is growing rapidly in late spring or early summer.
Remarks In two experiments, plants treated with glyphosate had no regrowth 1 year later.
Caution Glyphosate is a nonselective herbicide.
Site of action Group 9: inhibits EPSP synthase
Chemical family None generally accepted
picloram (Tordon)
Rate 0.5 lb ae/A or 0.5% concentration for application with a handgun sprayer.
Time Apply when cucumber is growing rapidly in the late spring or early summer.
Remarks Expect 80 to 100% control 1 year after treatment.
Caution Most formulations are restricted-use herbicides.
Site of action Group 4: synthetic auxin
Chemical family Pyridine
triclopyr (Garlon)
Rate 1 lb ae/A or 0.5% concentration for application with a handgun sprayer.
Time Apply when cucumber is growing rapidly in late spring or early summer.
Remarks Tests with the ester form had excellent results 1 year later. At 0.5 lb ae/A, results were less clear, but two of three plots had good results.
Caution See label for registered sites for triclopyr products' use.
Site of action Group 4: synthetic auxin
Chemical family Pyridine
triclopyr + 2,4-D (Crossbow)
Rate 0.5 lb + 1 lb ae/A (2 quarts/A Crossbow) or 1% concentration for handgun sprayer application.
Time Apply when cucumber is growing rapidly in late spring or early summer.
Remarks In two of three plots, results were good 1 year after treatment. Results were poor in the third plot.
Caution Check the Crossbow label to determine registered sites and rates.
Site of action (both) Group 4: synthetic auxin
Chemical family (triclopyr) pyridine; (2,4-D) phenoxy acetic acid