An aerial photo of a corn field with a substantial burcucumber infestation. The light green color is the burcucumber. At least 50% of the field is infested with the weed, which will make harvest extremely difficult this fall. If you look carefully, the weed can be seen in other parts of the field, but not matted down like the center portion of the field. InkFree News photo provided by Jeff Burbrink

By Jeff Burbrink
Extension Educator, Purdue Extension Elkhart County

Jeff Burbrink
Extension Educator, Purdue University Elkhart County

GOSHEN — I once heard you can harvest a field infested with burcucumber by pulling the combine into the field, parking at the edge of the infestation, turning on the reel and letting the weeds pull the crop in.

All kidding aside, burcucumber is one of the most troublesome weeds in agronomic crops. Its aggressive climbing growth habit, with tendrils attaching to anything nearby, can render acres of crop unharvestable.

The amount of burcucumber is increasing in our community. I have seen it in nearly every township, in ditches, along roadsides, in fields and even in a community garden.

A close up of a plant, showing the leaves and tendrils. This plant was growing in a roadside ditch. InkFreeNews photo provided by Jeff Burbrink.

An individual vine can reach lengths of 10 to 15 feet, and interlace with the other vines around it. Stems are sticky, hairy and the ridged, tendrils facilitate climbing. Leaves are somewhat heart-shaped, up to 8 inches long with 3-5 shallow lobes and pointed tips. Flowers are small, greenish-white; fruit are oval to elliptic, up to three-fourths inches long, pointed at tip, and covered with stiff bristles and numerous hairs. The fruit resembles a small cucumber or watermelon, is arranged in clusters of 3 to 10 individual seeds with sharp, bur-like spikes.

If you are aware of this weed in a field, consider harvesting the field last, or plan on doing a thorough cleaning of the combine before moving to the next fields. Combines are great at spreading the seeds. The University of Wisconsin has an excellent video on how to thoroughly clean a combine at tiny.cc/yn3zuz.

Next year, your weed control program should include both a preemergence plus a post emergence approach and may require additional mid-season passes to bring the weeds under control. This approach not only helps with burcucumber, but also with other troublesome weeds like marestail, the pigweed family and giant ragweed.

This photo shows how the burcucumber is beginning to climb from the ditch and enter the cornfield. InkFreeNews photo by Jeff Burbrink.

Fortunately, there are no known herbicides that burcucumber is resistant to, and there are some products that are very effective, if they are applied in a timely manner. One of the challenges with burcucumber is it can germinate all summer long, so multiple passes may be needed in those fields. You can see the recommendations in the 2022 Weed Control Guide for Ohio, Indiana and Illinois at tiny.cc/fn3zuz.

Pay particular attention to ditches, fence rows and other untilled areas. Burcucumber and many other weeds thrive in those areas, and quickly become part of the seed bank in your field. There is a lot of truth to the old saying one year of seeds equals 40 years of weeds.