English name: Powdery Mildew
The scientific name: Errecife Nicator (Uncinola Nicator) Erysiphe necator(Uncinula necator)
The type of disease: A fungal disease
family:Erysiphaceae
Symptoms
Powdery mildew appears as grayish-white powders on the upper surfaces of leaves and stems
And fruit clusters. Affected leaves may become disfigured, turn yellow or red, and eventually fall. On fruit, the fungus can cause russeting, cracking, and poor growth, resulting in reduced quality and yield.
Reasons
Powdery mildew is caused by the necator fungus Erysiphe (formerly known as Uncinula)necator, an obligate parasite that requires living host tissue to survive.
Propagation conditions
Powdery mildew prefers warm, dry conditions with temperatures between 70°F and 85°F (21°C and 29°C) and high relative humidity. The fungus produces numerous spores (conidia) that can be spread by wind, rain, or human activity.
Disease course
Powdery mildew fungi overwinter as cleistothecia (fruiting bodies) on bark, buds or debris in the vine. In the spring, these fruiting bodies release spores that initiate the first infection. The fungus then produces conidia that spread the disease throughout the growing season. The disease cycle continues as long as suitable conditions persist.
losses
Severe powdery mildew infection can lead to decreased photosynthesis, premature defoliation, poor fruit set, and reduced fruit quality, resulting in significant yield and economic losses.
Control strategy
An integrated approach that includes cultural practices, resistant varieties and fungicide applications is recommended for powdery mildew management.
Preventive measures
Plant resistant or tolerant varieties, ensure good air circulation in the vineyard, and avoid excessive nitrogen fertilization.
Organic/chemical control
For organic control, sulfur-based fungicides (eg wettable sulfur, sulfur of lime) can be effective when applied preventatively. Chemical fungicides containing active ingredients such as myclobutanil, quinoxifen, or trifloxystrobin may also be used according to label instructions.
References
http://ipm.ucanr.edu/PMG/r302101311.html https//www.uncovercolorado.com/wp-content/uploads/2021/06/grape-
powdery-mildew-1536×1024.jpg
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