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Investigating Pokeweed Management in Pennsylvania Field Crops

To learn more about the biology of pokeweed and how it behaves so we can better time control tactics

Common pokeweed is a native perennial weed with a large, persistent taproot. It is capable of producing an abundance of seeds; previous research has reported 150 berries per plant and about 10 seeds per berry so well over 1000 seeds per plant. Like other weeds, pokeweed competes with the crop for nutrients, water, and sunlight, potentially reducing both crop yield and quality. Plant toxicity is also a concern with pokeweed. At a young age, pokeweed is edible if cooked; however, the mature plants are poisonous. Pokeweed populations seem to be on the rise in recent years in Pennsylvania field crops. There may be several reasons for this including the increase in no-till acres where plowing used to control or suppress pokeweed, and secondly due to the reduction in the use of soil residual herbicides in both corn and soybean.

Our research involves two main goals. The first is to learn more about the biology of pokeweed and how it behaves so we can better time control tactics. One of our studies involves quantifying the emergence period of pokeweed seedlings. Although there is a peak emergence period in late spring, pokeweed seedlings can be seen emerging from early spring to early fall. Controlling seedlings throughout the season is key, since mid and late summer seedlings have the potential to survive the winter and regrow the following spring. The second main goal of our research is to examine the effectiveness of different herbicides for pokeweed control in no-till soybean and corn. Thus far, glyphosate (Roundup®) has provided good control, both by itself and in combination of other herbicides. Timing of herbicide application appears to be important, however, since we have seen that glyphosate provides varied control depending on application timing.  We are currently assessing the long-term control potential for several different herbicide programs and will know more this summer.

About the Researchers:
Kelly Patches grew up on a dairy farm in Lebanon County and has experience working with Penn State Extension. She earned her Bachelor’s degree in Environmental Soil Science from Penn State in 2010. Kelly is currently in her second year of her Master’s degree in Agronomy at Penn State. Along with her advisor, Dr. Bill Curran, she is conducting research on pokeweed and looking into its biology and management in agronomic field crops.

Contact Information:
Phone:  814-863-7112
Email:  pokeweed@psu.edu

Bill Curran
E-mail: wcurran@psu.edu
Phone: 814-863-1014