Best practices for burcucumber control in corn fields

By Blake Jackson

Burcucumber can be a significant problem in corn fields, but it can be effectively managed through early harvesting for silage.

Extension agronomist Dwight Lingenfelter emphasizes the importance of prioritizing burcucumber control as corn silage harvest approaches.

Burcucumber seeds can germinate and emerge late in the season, especially under moist conditions. Often, farmers don't notice burcucumber until it grows above the corn canopy.

Research conducted by Penn State has shown that ensiling green burcucumber seed can effectively kill young seeds. However, ensiling mature seeds has limited impact on their viability.

Studies indicate that only 2% of immature (green or cream-tan) burcucumber seeds remain viable after an eight-week ensiling period, compared to 87% of mature (dark brown) seeds.

This suggests that harvesting corn for silage early in the season can prevent the production of viable burcucumber seeds in infested fields. Additionally, silage harvest eliminates the risk of mature seeds reentering the field through the combine.

If burcucumber cannot be removed through silage harvest, there are limited herbicide options available.

Herbicides like glyphosate cannot be applied until the grain is mature, and other herbicides like Peak, dicamba, Callisto, and Liberty must be applied before the V8 corn stage. Using drones or high-clearance sprayers to apply herbicides at this time of year for burcucumber control is not recommended.

The next opportunity for herbicide application would be as a harvest aid (or weed desiccant) just before grain harvest.

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