April
2007
, Volume
91
, Number
4
Pages
421
-
429
Authors
Greg
English-Loeb
and
Andrew P.
Norton
,
Department of Entomology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456
; and
David
Gadoury
,
Robert
Seem
, and
Wayne
Wilcox
,
Department of Plant Pathology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456
Affiliations
Go to article:
RelatedArticle
Accepted for publication 19 October 2006.
Abstract
ABSTRACT
We evaluated the efficacy of a mycophagous tydeid mite, Orthotydeus lambi, in controlling grape powdery mildew on mature vines of nine different grape cultivars and one unnamed hybrid grown in an experimental vineyard over a 3-year period. O. lambi became well established on all vines where they were released. However, some cultivars supported higher densities than others, depending on, among other factors, the presence and abundance of leaf trichomes in vein axils (domatia). The establishment of O. lambi substantially reduced powdery mildew on foliage and fruit, although the magnitude of disease suppression was greater on some grape genotypes than others, depending on mite density and innate susceptibility to grape powdery mildew. Treatments where O. lambi was used alone were as effective as fungicide. Significantly better disease control was found in treatments with both mites and fungicides. The mass of pruning material and leaf photosynthetic rates were significantly greater for vines with O. lambi, fungicide, or a combination of mites and fungicide compared with untreated vines. The combination of mites and fungicide resulted in significantly greater yield than mites or fungicide alone. Our results illustrate the potential of O. lambi for biological control of grape powdery mildew but also highlight limitations related to differences among grape genotypes in innate susceptibility to mildew and suitability for mites.
JnArticleKeywords
Additional keywords:
Tydeidae,
Uncinula necator,
viticulture,
Vitis labrusca,
V. riparia,
V. vinifera
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ArticleCopyright
© 2007 The American Phytopathological Society