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Outline
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Influence of Time of Emergence on the Area of Influence of Nutsedges in Bell Pepper
  • Bielinski M. Santos
  • James P. Gilreath
  • Camille Esmel
  • Myriam Siham
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Why Nutsedge?
  • Nutsedge (Cyperus spp.) could cause total bell pepper yield loss.


  • Difficult and expensive to control.


  • No postemergence herbicides for nutsedge control in bell pepper.
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What About Fumigation?
  • Methyl bromide will not longer be an option.
  • MBr alternatives do not provide consistent control.
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Nutsedge Interference
  • Previous studies have shown the effect of low nutsedge densities on pepper.
    • About 20% with 50 plants/m2.


  • No research has been conducted on the effect of time of weed emergence on pepper.


  • Nutsedge starts sprouting between 3 and 5 weeks after fumigation.
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Interference Studies
  • Replacement series studies.
    • Determine which species is more competitive.
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Interference Studies
  • Replacement series studies.
    • Determine which species is more competitive.


  • Additive studies.
    • Determine the effect of weed density on yield.
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Interference Studies
  • Replacement series studies.
    • Determine which species is more competitive.


  • Additive studies.
    • Determine the effect of weed density on yield.


  • Critical period studies.
    • Determine weed thresholds.
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Interference Studies
  • Replacement series studies.
    • Determine which species is more competitive.


  • Additive studies.
    • Determine the effect of weed density on yield.


  • Critical period studies.
    • Determine weed thresholds.


  • Area of influence studies.
    • Determine the effect of a single weed on the crop.
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Area of Influence
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Objective
  • Examine the effect of time of emergence on the area of influence of nutsedges in bell pepper.
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Materials and Methods
  • Two field trials at the GCREC-UF in Bradenton.


  • ‘Capistrano’ bell pepper in double rows.
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Materials and Methods
  • Two studies:
    • Yellow nutsedge (C. esculentus).
    • Purple nutsedge (C. rotundus).

  • Time of emergence:
    • 1, 2, 3, 4, and 5 weeks after transplanting.
    • Weeds with 2 leaves.
    • Weed-free control.

  •  Pepper yield determined at:
    • 0, 30, 60, 90 cm from the weed.
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Area of Influence
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Materials and Methods
  • Randomized complete block design with 5 replications.


  • MANOVA:
    • Non-independent yield observations.

  • Standard errors:
    • Relative pepper yield (weed-free = 100%).
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What did we learn?
  • YN is more competitive than PN:
    • Confirms previous findings.

  • YN at a density of 0.33 plants/ft row:
    • 1 YN for 6 pepper plants (0-30 cm).
    • Emerging 1 WAT, yield reductions between 32 and 57%.
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What did we learn?
  • PN at a density of 1 plant/ft row:
    • 1 PN for 2 pepper plants (0 cm).
    • Emerging 1 WAT, yield reduction of 31%.

  • Low weed densities matter!!!