PPI Spring Meeting 2001 - Abstract

Weed Management in Cucumbers

David Monks and Roger Batts

Department of Horticultural Science, North Carolina State University

Weeds can reduce quality and yield of pickling cucumbers, and can interfere with harvest. In 1978 G.H. Friesen determined that cucumbers must be maintained weed-free from 12 to 36 days after emergence for optimum yield, depending on the year. He also found that only 5% of a natural population of weeds left 24 days after crop emergence reduced yield approximately 50% [Weed Science volume 26(6) 626-628]. The weeds in his study were common lambsquarters, common ragweed and longspine sandbur and the average population of weeds was 191 weeds per m2. Based on this research, pickling cucumbers must be maintained near weed-free most of the growing season for optimum yield and quality.

The standard program that growers use for maintaining cucumbers weed-free in North Carolina usually includes Curbit (ethalfluralin) applied to the soil surface immediately after seeding. Growers sometimes use Prefar (bensulide) instead of Curbit. Cucumbers are then cultivated as needed and Alanap (naptalam) is sometimes applied postemergence before cucumbers start to vine. Alanap provides postemergence control (suppression) of certain emerged broadleaf weeds and late season preemergence broadleaf weed control. Poast (sethoxydim) is used in fields where grass weeds are a problem. Select (clethodim) was recently registered in cucumbers and it gives postemergence grass control in similar situations as Poast. Thus, growers have two herbicides for controlling emerged grasses.

There are two herbicides that will be available soon for cucumber growers to use. They include Sandea (halosulfuron) which gives good postemergence control of nutsedge, pigweed and certain other broadleaf weeds, and Command (clomazone) which gives good preemergence control of many weeds but is weak on pigweed. Data to support the registrations of these products in cucumber comes from extensive testing at North Carolina State University as well as the IR-4 Project, a program to clear pest control agents for use in minor crops.

For further information, contact:

• Dr. David W. Monks, Departmental Extension Leader
  • Department of Horticultural Science
  • North Carolina State University, Raleigh, NC 27695-7609
  • Telephone: 919-515-5370; Fax: 919-515-7747
  • E-mail: david_monks@ncsu.edu
• Mr. Roger B. Batts, IR-4 Coordinator
  • Department of Horticultural Science
  • North Carolina State University, Raleigh, NC 27695-7609
  • Telephone: 919-515-1668; Fax: 919-515-7747
  • E-mail: roger_batts@ncsu.edu

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