Comparison of weed-suppressing cover crop species for relative control effectiveness of Galinsoga quadriradiata in agricultural fields in the northeast United States

Conry, Tom
Jon Atwood, PhD
Department of Environmental Studies
Galinsoga quadriradiata Ruiz and Pavon is a common agricultural weed of the northeast United States. The species thrives in loose, fertile, and repeatedly disturbed soils (i.e. farm fields), where it quickly out-competes many vegetable crop species. The pressure of this weed results from its rapid maturation, prolific seed set, and lack of seed dormancy. The effectiveness of sustainable control by cover crop interference (competition) was studied. Three cover crop species (Echinochloa frumentacea, Fagopyrum esculentrum, and Sorghum bicolar var. Sudanese) were tested for general and relative success in reducing weed population and/or flowering. All cover crop treatments resulted in significant decreases in numbers of G. quadriradiata flowers and stems. Statistically significant differences in effectiveness were not shown among the three cover crop species, possibly as a result of small sample sizes. The number of Galinsoga flowers was lowest in plots treated with Fagopyrum or Echinochloa, and highest in areas treated with Sorghum; the number of Galinsoga stems was lowest in plots treated with Sorghum and greatest in plots treated with Fagopyrum. The research provides guidance to sustainable farmers and can be used to inform further study in effective ecological control of G. quadriradiata.

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