Going underground: excavation of yellow nutsedge

Today our Staff Research Associate, Maren Mochizuki, will share with us a glimpse inside a recent day as our office works to better understand the growth patterns of the yellow nutsedge.

Yellow nutsedge is a difficult weed to control because the plant produces new shoots via underground stems called tubers (similar to a potato); a few plants can turn quickly into an infestation!  Costly and labor-intensive hand weeding has been the only means of management because current herbicides are not effective.

Strawberry bed with yellow nutsedge

To understand the underground growth of this weed, we (Oleg Daugovish, Ventura County UCCE Farm Advisor; Emmanuel Gonzalez, Ventura County UCCE Lab Assistant; and Maren Mochizuki, Ventura County UCCE Staff Research Associate) sliced a cross section of an infested strawberry bed.  We were hoping to answer the following questions: How deep are the tubers?  About how many tubers are produced from each shoot?

After cutting the cross section and pushing it onto a bed of nails to hold it, we were able to lift it onto the truck tailgate and drive it to a water source to wash a few cubic feet of soil from the nutsedge underground stem/root system.  We were surprised to find that the tubers were not as deep as we expected (no deeper than 8 inches) and we counted several hundred tubers from our cross section, or about 3 per plant.

Yellow nutsedge tubers

The research team has another multi-year study using mechanical barriers such as layering plastic mulch, then paper, and another layer of plastic prevents germination of yellow nutsedge in strawberry beds as they continue to develop ways to handle this problematic weed. The mechanical barrier study will be featured in tomorrow’s blog posting.

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