Laser Weeding in Vegetable Crops

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Thierry Besancon, Rutgers and Lynn Sosnoskie, Cornell held an industry field day at the Rutgers Agricultural Research and Extension Center (RAREC) on May 13th to demonstrate a laser weeding system in spinach, kale and other vegetables. They have been doing research on this system since 2024. Following is a summary of results from their handout. First, what is laser weeding?

Laser weeding uses cameras, artificial intelligence (AI) and high-energy lasers to identify and kill weeds without herbicides. The system scans the soil surface, recognizes weeds in real time and briefly targets the growing point of the weed with a laser pulse. The technology works best on very small weeds (cotyledon to 2-leaf stage).

Key Findings

  1. Excellent control of small broadleaf weeds
    a. Laser weeding provided weed control comparable to and in some cases better than standard herbicide programs for weed such as:
    i. Common lambsquarters
    ii. Common ragweed
    b. Across trials, laser treatments reduced weed biomass by more than 97% compared with non-treated plots.
  2. Very low crop injury
    a. Crop injury from the laser system remained minimal:
    i. Approximately 1% in peas and 2-3% in spinach and beets
    b. In spinach, laser weeded plots often produced larger plants than herbicide treated plots because some herbicides caused crop stunting.
  3. Weed species matter
    a. The laser system performed best on upright broadleaf weeds and was less consistent for purslane and annual grasses (foxtail and barnyard grass)
  4. Timing is critical
    a. Laser weeding was most effective when weeds were very small, ideally cotyledon to 2 leaf stage. Multiple passes were needed during the season to control later weed flushes.
  5. Herbicides + laser may work best together.
    a. Combining residual herbicides with laser weeding often improved overall weed control and reduced the number of weeds the laser needed to target. This combination also improved operating speed of the machine.

Current Challenges
Although results were very promising several limitations remain:

  1. Equipment cost
  2. Laser weeding is slower than spraying herbicides
  3. Multiple passes may be required
  4. Performance can vary by weed species and weed size

Take Home Message
Laser weeding is not likely to replace herbicides entirely in the near future, but it shows strong potential as part of integrated weed management programs for specialty crops, especially where herbicide options are limited or crop safety is a concern.