Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Impact of Leaf Mining on the Growth of Portulaca oleracea (Common Purslane) and Its Competitive Interaction with Beta vulgaris (Sugarbeet)

Robert F. Norris
Journal of Applied Ecology
Vol. 34, No. 2 (Apr., 1997), pp. 349-362
DOI: 10.2307/2404881
Stable URL: http://www.jstor.org/stable/2404881
Page Count: 14
  • Read Online (Free)
  • Download ($18.00)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Impact of Leaf Mining on the Growth of Portulaca oleracea (Common Purslane) and Its Competitive Interaction with Beta vulgaris (Sugarbeet)
Preview not available

Abstract

1. The combined attack by leaf mining larvae of the sawfly, Schizocerella pilicornis, and the weevil, Hypurus bertrandi, typically resulted in over 80% defoliation of fieldgrown Portulaca oleracea plants in the Central Valley of California. Incorporation of the insecticide aldicarb into the soil prior to planting protected the weed from attack by the insects. Comparison of insecticide-treated and non-treated plants demonstrated that the leaf mining reduced weed growth by 60-70%. 2. Under replacement series pot experiment conditions, leaf mining reversed the competitive interaction between sugarbeet and P. oleracea. Sugarbeet grew best in the presence of P. oleracea plants that were attacked by leaf miners; relative crowding coefficients for sugar beet exceeded 1.0. When P. oleracea was protected from leaf-miner attack, relative crowding coefficients for sugarbeet were all below 1.0. 3. Portulaca oleracea caused up to 80% yield loss in sugarbeet in additive field competition experiments. The magnitude of the sugarbeet yield loss increased with increasing density of P. oleracea; between 0.5 and 3.0 P. oleracea plants per m of crop row caused an economic loss depending on year. Soil-applied aldicarb insecticide did not alter the competitive interaction in 3 years out of 4, although the insecticide substantially protected P. oleracea from leaf mining. 4. Although P. oleracea was severely damaged by leaf miner feeding, this injury did not result in sufficient biological weed control to reduce the need for use of other weed management techniques.

Page Thumbnails

  • Thumbnail: Page 
349
    349
  • Thumbnail: Page 
350
    350
  • Thumbnail: Page 
351
    351
  • Thumbnail: Page 
352
    352
  • Thumbnail: Page 
353
    353
  • Thumbnail: Page 
354
    354
  • Thumbnail: Page 
355
    355
  • Thumbnail: Page 
356
    356
  • Thumbnail: Page 
357
    357
  • Thumbnail: Page 
358
    358
  • Thumbnail: Page 
359
    359
  • Thumbnail: Page 
360
    360
  • Thumbnail: Page 
361
    361
  • Thumbnail: Page 
362
    362