Correct option is B
The correct answer is: (B) Plasmopara viticola
Explanation:
Downy mildew of grapes is a serious fungal disease caused by Plasmopara viticola, an oomycete pathogen that thrives in warm and humid conditions.
It primarily affects the leaves, stems, and fruits of grapevines, leading to yellowish oily spots, white fungal growth on the underside of leaves, and defoliation. Severe infections can result in reduced fruit yield and poor grape quality.
Information Booster:
Key Points about Downy Mildew in Grapes:
Causal Organism: Plasmopara viticola (an oomycete pathogen).
Symptoms:
White cottony fungal growth on the underside of leaves.
Premature leaf drop, affecting photosynthesis.
Fruit shriveling and poor grape quality.
Favorable Conditions:
High humidity (above 85%) and warm temperatures (18-25°C).
Continuous rainfall enhances disease spread.
Control Measures:
Use of resistant varieties.
Application of fungicides like Bordeaux mixture (1% copper sulfate + lime solution), Metalaxyl, or Mancozeb.
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