This drone photo gives an idea how this weed can take over an entire field by August. The old joke is you can pull a combine to the edge of the field and reel in the crop by pulling in the vines. Photo by Jeff Burbrink.

By Jeff Burbrink
Ag & Natural Resources Extension Educator, Purdue Extension LaGrange County

Jeff Burbrink

LAGRANGE — When you talk to a farmer that is experiencing his first go around with burcucumber, the first thing they usually say is “This crazy stuff took out 3-4 acres!” People with years of experience with the weed talk about burcucumber with the sort of contempt that is commonly reserved for the skunk that sprayed their dog.

Burcucumber (Sicyos angulatus) is an aggressive, viny, summer annual broadleaf weed that can be troublesome in corn and soybean fields. Key identifying characteristics of burcucumber are round to heart-shaped leaves, sticky hairy and ridged stems, vines with long tendrils, and spiny seed clusters (bur-like seeds). Burcucumber may be confused with the less common wild cucumber, however, wild cucumber is less likely to invade into crop fields.

Burcucumber seedlings have large, oval-shaped cotyledons (first leaves) and will emerge late into the growing season. It often emerges in several flushes through the growing season, coming up from depths are deep as 6 inches below the soil surface!

This photo shows burcucumber growing in a nearby ditch, and finding its way into the fields. Control on the edge of fields is critical. Photo by Jeff Burbrink.

Burcucumber vines can grow over 20 feet long and twine around corn plants, thereby lodging the corn plants and causing severe harvest problems. Burcucumber begins to flower in August and continues flowering until a killing frost. Seed clusters are composed of up to 30 seeds. The hard seed coat contributes to a prolonged seed life, thereby contributing to persistence and infestation of this weed for several years in crop fields.

Burcucumber can emerge in multiple flushes throughout the growing season, so an effective control program must include a two-pass, pre-emergent program followed by post herbicide program. Post programs should include an effective residual herbicide to control late-emerging burcucumber flushes.

If you run across this nasty weed at harvest, its best to avoid running it through the combine. Same that area for last, and then clean the combine out thoroughly, or it will likely e spread to the next fields.

Also, pay close attention to the field boundaries such as fence rows, borders with forested areas, ditch banks and other non-crop areas. It can easily originate in those areas, and set you up for a challenging future.