In periods of pervasive wet and rainy weather, growers must be prepared for the possible ravages of Phytophthora and Pythium infections. Phytophthora fungi are commonly known as ‘water molds.’ But despite the innocuous name, they can be some of the most devastating plant pathogens known to man. In the mid-19th century, more than one million…
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Plant Diseases
What Determines Whether a Plant Pathogen Will Cause Disease?
With the great majority of diseases afflicting crops, we are told to pay very close attention to moisture on flowers, fruit, and shoots, as well as moisture in the soil. This is because it’s understood that most disease organisms thrive under wet or rainy conditions. This seems logical, after all. Fungi, for instance, require a…
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Preparing Roses Against Common Winter Diseases
The primary concerns for rose growers as fall transitions to winter should be: Minimizing the carryover of inoculum—spores and fragments of fungal pathogens which can cause disease the following spring; Reducing populations of nematodes and other soil-borne disease pressures to create ideal growing conditions for root flush in January and February; and Maintaining rich soil…
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