Relationship between leaf emergence and optimum spray timing for leaf blotch (Rhynchosporium secalis) control on winter barley

  • Young C
  • Thomas J
  • Parker S
 et al. 
  • 11

    Readers

    Mendeley users who have this article in their library.
  • 4

    Citations

    Citations of this article.

Abstract

For wheat, the optimum time to apply fungicide to control disease on a given leaf layer is usually at, or shortly after, full leaf emergence. Data from field experiments on barley were used to investigate whether the same relationship was applicable to control of leaf blotch on barley. Replicated plots of winter barley were sown in the autumns of 1991, 1992 and 1993 at sites in southwest England with high risk of Rhynchosporium secalis infection. Single fungicide treatments at four doses (0·25, 0·5, 0·75 or 1·0 times the label rate) were applied at one of eight different spray times, starting in mid-March in each year, with intervals of 10–11 days between spray timings. Disease was assessed every 10–11 days and area under the disease progress curve (AUDPC) values were used to construct fungicide dose by spray time response surfaces for each of the upper four leaves, for each year. Spray timings shortly before leaf emergence were found to minimize the AUDPC for each year and leaf layer, and also the effective dose (the dose required to achieve a specified level of control), similar to wheat. Fungicide treatments on barley were effective for a longer period before leaf emergence than afterwards, probably because treatments before emergence of the target leaf reduced inoculum production on leaves below. This partly explains why fungicides tend to be applied earlier in the growth of barley compared with wheat.

Author-supplied keywords

  • Barley leaf blotch
  • Fungicide timing
  • Leaf emergence
  • Rhynchosporium secalis

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Get full text

Authors

  • C. S. Young

  • J. M. Thomas

  • S. R. Parker

  • N. D. Paveley

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free