Contrary to popular belief, crabgrass（马唐草） does not thrive in lawns, gardens and farm fields by simply crowding out other plants. A new study in ACS' Journal of Agricultural and Food Chemistry has found that the much-despised weed actually produces its own herbicides that kill nearby plants. Chui-Hua Kong and colleagues point out that crabgrass is not only a headache for lawns and home gardens, but also a major cause of crop loss on farms. Scientists long suspected, but had a hard time proving, that the weed thrived by allelopathy（植化相克）. From the Greek "allelo-," meaning "other," and "-pathy," meaning "suffering," allelopathy occurs when one plant restricts the growth of another by releasing toxins¹. They set out to determine if crabgrass has this oppressive ability.

 

Kong's team isolated² three chemicals from crabgrass that affect the microbial communities in nearby soil and did indeed inhibit³ the growth of staple⁴ crops（主要作物） wheat, corn and soybeans. "The chemical-specific changes in [the] soil microbial community generated a negative feedback on crop growth," the scientists said, noting that the chemicals also would have a direct toxic⁵ effect on other plants.

 

The authors acknowledge funding from the National Natural Science Foundation of China.

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