July
1997
, Volume
81
, Number
7
Pages
787
-
790
Authors
S. L.
Reichard
,
Graduate Research Assistant
,
R. M.
Sulc
,
Assistant Professor, Department of Horticulture and Crop Science
,
L. H.
Rhodes
,
Associate Professor, Department of Plant Pathology
, and
M. M.
Loux
,
Associate Professor, Department of Horticulture and Crop Science, The Ohio State University, Columbus 43210
Affiliations
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RelatedArticle
Accepted for publication 31 March 1997.
Abstract
ABSTRACT
This study was conducted to determine whether herbicides and adjuvants registered for poste-mergence use in alfalfa have an effect on Sclerotinia crown and stem rot (SCSR). In a controlled environment, disease severity index (DSI) of alfalfa seedlings was reduced by pronamide and 2,4-DB compared with the untreated control, whereas bromoxynil and 13% sethoxydim + petroleum-based adjuvant (PBA) increased DSI. In the field, disease severity in all herbicide treatments was similar to that in untreated alfalfa. In a second controlled-environment study, pronamide and 2,4-DB reduced DSI compared with the no herbicide control when seedlings were inoculated 1 day after herbicide application, but this protective effect was not observed when seedlings were inoculated 8 days or longer after herbicide application. The results demonstrate that several herbicides are capable of suppressing or enhancing SCSR severity in a controlled environment if seedling inoculation occurs soon after herbicide application; however, the residual effect of these herbicides on SCSR appeared to be much shorter than the 4- to 6-week infection period occurring in the field.
JnArticleKeywords
Additional keywords:
Medicago sativa,
Sclerotinia trifoliorum
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ArticleCopyright
© 1997 The American Phytopathological Society