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Reflective mulch with seedling peppers. Mulches

White or silver mulches under cucurbits may lower insect numbers and incidence of insect transmitted viruses during early growth until vines cover it.

Black mulch or mulch co-extruded with black on the bottom will reduce weeds; however some weeds like nutsedge will not be easily controlled this way.

Clear or black mulches just prior to planting are better for heating the soil to promote early germination


Clear plastic mulches can effectively solarize the soil and reduce weeds, nematodes, and some diseases. Solarization is very effective in reducing disease caused by Verticillium and Fusarium. However, solarization often fails to provide economic control of vine disease decline (Monosporascus cannonballus) and charcoal rot.

  • Apply clear plastic mulch over moist, cultivated soil or pre-formed beds during the peak of summer (late June to the end of August)
  • Leave in place for a minimum of 3 weeks. Better results may be expected with longer periods of solarization; therefore, leave the plastic in place for as long as possible.
  • Unlike the use of mulches under growing plants, remove plastic used for solarization before planting.

Statewide IPM Program, Agriculture and Natural Resources, University of California
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