Horticulture is the fastest-growing sector of American
agriculture, and in 2004 Maine ornamental plant sales were valued at
$114 million. One of the challenges facing commercial growers,
however, is powdery mildew, a common fungal disease that spreads
quickly under high-moisture conditions such as those found in
greenhouses and during Maine’s summer growing season. While it is
impossible to assign a value to the financial loss caused by powdery
mildew, individual growers lose part or all of specific crops due to
this disease every year. UMaine researchers are investigating the
possibility of controlling powdery mildew through use of
plant-growth regulators rather than fungicides. The researchers
established three field trials at the University of Maine, and
evaluated the effects of different plant-growth regulators on ‘Frans
Schubert’ summer phlox and ‘UMaine’ daisy (Rudbeckia).
Results from this research indicate that plant-growth regulators can
control powdery mildew infection on herbaceous plants during the
growing season. The findings will be used to develop practical
recommendations for Maine’s horticulture industry.
Photo credit: Tom Barnes, University of Kentucky @ USDA-NRCS
PLANTS Database / Barnes, T.G. & S.W. Francis. 2004. Wildflowers and
ferns of Kentucky. University Press of Kentucky.
