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November, 2007
Plant Disease
magazine, November 2007 issue
Three new races of the spinach
downy mildew pathogen identified
http://apsjournals.apsnet.org/doi/interp/10.1094/PDIS-91-11-1392
Authors: B. M. Irish, United States Department of
Agriculture-Agricultural Research Service, Tropical Agriculture
Research Station; J. C. Correll, Department of Plant Pathology,
University of Arkansas; S. T. Koike, University of California
Cooperative Extension; and T. E. Morelock, Department of
Horticulture, University of Arkansas
ABSTRACT
Downy mildew is the most economically important disease of
spinach worldwide. During the past few years, spinach
cultivars resistant to the previously described downy mildew
races were observed to be severely affected in both the
United States and the European Union. Four downy mildew
isolates were collected from California and The Netherlands
and characterized for race on spinach differentials. The
results led to the description of three new races of the
downy mildew pathogen, designated races 8, 9, and 10. Four
differential spinach cultivars with resistance to the
previous races were used to distinguish the three new races.
The three new races also were used to evaluate the disease
reactions of contemporary commercial spinach cultivars in
greenhouse experiments. In addition, examining downy mildew
isolates collected in California and Arizona between 2004
and 2006 revealed that the new race 10 predominated in the
areas sampled. Characterizing downy mildew races and
identifying spinach cultivars with resistance to new races
will provide producers the most efficient means for disease
management.
Plant disease impacts cassava production in West Africa
http://apsjournals.apsnet.org/doi/interp/10.1094/PDIS-91-11-1430
Authors: W. Msikita, Pennsylvania Department of Agriculture; and
H. Baimey and B. D. James, International Institute of Tropical
Agriculture, Biocontrol Center for Africa
New study evaluates the effectiveness of soybean rust
fungicides
http://apsjournals.apsnet.org/doi/interp/10.1094/PDIS-91-11-1450
Authors: M. R. Miles, United States Department of
Agriculture-Agricultural Research Service (USDA-ARS), National
Soybean Research Center; C. Levy, Commercial Farmers Union of
Zimbabwe; W. Morel, Ministerio de Agricultura y Ganadería,
Centro Regional de Investigación Agrícola (CRIA); T. Mueller and
T. Steinlage, Department of Crop Sciences, University of
Illinois; N. van Rij, KwaZulu-Natal Department of Agriculture
and Environmental Affairs; R. D. Frederick, USDA-ARS, Foreign
Disease-Weed Science Research Unit; and G. L. Hartman, USDA-ARS,
National Soybean Research Center, Department of Crop Sciences,
University of Illinois
Spotlight Articles Selected by the Editors of Plant Disease,
Phytopathology, and Molecular Plant-Microbe Interactions (MPMI)
Plant Disease Editor's Pick
What factors influence the
latent periods of foliar fungal pathogens? The latent period
for Septoria blotch, caused by Septoria tritici on wheat, is
11 to 42 days. M. Henze, M. Beyer, and colleagues used
meteorological data from 39 sites to calculate a field
estimate of 20 days. Read their article, Characterizing
Meteorological Scenarios Favorable for Septoria tritici
Infections in Wheat and Estimation of Latent Periods to see
how the latent period changed with temperature, latitude,
and precipitation.
http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-91-11-1445
The development and spatial spread of exotic and potentially
devastating soybean rust in the southeastern U.S. in 2005
and 2006 was analyzed using USDA records.
The disease developed late both years, which was attributed
to slow build-up of the fungus on the overwintering host,
kudzu, and a narrow window of opportunity for disease
establishment during reproductive development of soybean.
http://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-97-11-1428
MPMI Editor's Pick
In the November issue of
MPMI, Halim et al. studied the response of potato plants
that cannot accumulate salicylic acid to Phytophthora
infestans. As previously reported, there was little
difference in lesion size. However, pathogen growth was
greatly enhanced in the nonaccumulating plants.
http://apsjournals.apsnet.org/doi/abs/10.1094/MPMI-20-11-1346
An online subscription is needed to access the full articles.
Plant Disease is the leading
international journal for rapid reporting of research on new
diseases, epidemics, and methods of disease control.
Phytopathology is the premier international journal for articles
on fundamental research that advances understanding of the
nature of plant diseases, the agents that cause them, their
spread, the losses they cause, and measures that can be used to
control them.
Molecular Plant-Microbe Interactions (MPMI) is the
groundbreaking journal for publication of original, refereed
research on the molecular biology and molecular genetics of
pathological, symbiotic, and associative interactions of
microbes with plants and insects with plants. |
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