ARS | Publication request: Application of bio-active organic mulch for suppressing purple and yellow nutsedges in tomato production

Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: June 27, 2012
Publication Date: N/A

Technical Abstract: When methyl bromide has been totally phased out, the losses due to nutsedges (Cyperus rotundus and C. esculentus) are expected to increase in conventional horticultural crops. Organic production will continue to suffer due to a lack of effective weed control measures. Thus, nine organic hays (shoot straw of bahiagrass, cogongrass, cowpea, millet, yellow nutsedge, sorghum Sudangrass, sunnhemp, and rye), three green mulches (cowpea, millet, and sorghum Sudangrass), two infested hay (cogongrass infested with the biocontrol fungus Dactylaria higginsii [Dh] and cogongrass infested with the fungus Trichoderma sp. [Tri]), and two plastic mulches (black and IRT) were tested for their efficacy in suppressing purple and yellow nutsedge growth in a raised bed tomato (cv. Tygress) field. The black plastic mulch and the Dh-infested cogongrass consistently reduced nutsedge emergence and growth more than the other organic mulches and the IRT plastic mulch. However, there were no disease symptoms developed on nutsedge plants when Dh-infested cogongrass was used as mulch. Among the organic mulches, the greatest suppressive effect on nutsedge was found when using infested cogongrass with Dh or Tri, cowpea, sunnhemp, Bahiagrass, and congongrass hays. Both plastic mulches (Black and IRT) and Tri-infested cogongrass enhanced the total yield of tomato and also influenced the proportion of larger fruits.