University of California researchers want to evaluate glyphosate resistance in various weed populations and could use your help.

Of current interest is glyphosate resistance in junglerice (Echinochloa colona) throughout California.

Lynn Sosnoskie, assistant project scientist and weed researcher at UC Davis, is heading up the study. She is particularly interested in working with farm advisers, pest control advisers, farmers and ranchers, farm managers, pesticide applicators, master gardeners, horticulturalists, and plant enthusiasts.

“We would like California citizens, particularly those closely involved with, or interested in, agriculture and horticulture to collect seed from mature junglerice plants and send that seed to us for evaluation,” Sosnoskie said.

The study seeks to:

  • Determine the distribution of glyphosate-resistant biotypes using field collections which will be screened in UC Davis greenhouses. The physiological and molecular mechanisms of resistance will be evaluated using chromatographic and molecular genetics approaches. 
  • Describe the competitive ability of the resistant and susceptible biotypes under different growing environments. This will be determined in field, greenhouse, and growth chamber studies.
  • Evaluate alternative control strategies. Herbicide efficacy will be tested and demonstrated in commercial orchards and vineyards throughout the state.

Glyphosate resistance is of particular importance to small-acreage, specialty crops due to the limited availability of registered herbicides. The evolution and spread of glyphosate-resistant weeds further limits weed management options and increases the cost of producing these crops. 

Junglerice is a clumping, summer annual grass whcih can grow up to three feet in diameter. Mature plants grow along the ground or maybe somewhat upright.

Leaves are hairless and a dull green color. Leaves may also have dark red or purple bands running laterally across. Flowers bloom from June through October. The flower heads are about 1-6 inches long with short, compact branches.

Do not collect seed until the seed head has matured. If you harvest too soon, seed may not be viable and will not germinate. 

Shatter stage

Grass seed is ready to harvest when it heads start to shatter (i.e. are drying out and fall off in your hand). Harvest seed from at least 10-20 plants, if possible.

Cut stems at least 2-3 inches below the bottom of the seed head. Be careful to ensure that the seeds don't fall out.

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Place all of the seed heads into coin envelopes, manila envelopes, or paper bags. Store in a cool, dry place so the plant tissue dries down completely.

Mail or personally deliver the samples to UC Davis at the following address:

Lynn Sosnoskie, Assistant Project Scientist
Department of Plant Sciences, MS-4, UC Davis
One Shields Avenue, Davis, CA 95616

For more information, contact Lynn Sosnoskie at (229) 326-2676 or lmsosnoskie@ucdavis.edu.