Sclerospora graminicola causes downy mildew in millets like pearl millet and foxtail millet. The correct answer is Green ear disease, a systemic symptom of downy mildew where infected panicles turn green and leafy, though options list it separately from “downy mildew of pea/mustard.”

Option Analysis

• Downy mildew of pea: Caused by Peronospora viciae, not Sclerospora graminicola. Features white fungal growth on pea leaves/pods.

• Downy mildew of mustard: Caused by Peronospora parasitica, affecting Brassica leaves with grayish-white patches.

• Green ear disease: Correct. Sclerospora graminicola (oomycete) causes downy mildew of pearl millet (Pennisetum glaucum), with systemic “green ear” where inflorescences convert to leafy structures instead of grains. Also affects foxtail millet with leaf yellowing/cracking.

• Wart of potato: Caused by Synchytrium endobioticum (fungus), producing powdery galls on tubers/stems.

Introduction to Sclerospora Graminicola Green Ear Disease

Sclerospora graminicola green ear disease devastates millets like pearl millet, converting grain heads into green leafy “ears” via systemic oomycete infection. Unlike downy mildew of pea or potato wart, it targets grasses with white sporulation.

Pathogen and Hosts

Sclerospora graminicola, an obligate oomycete, infects Pennisetum glaucum (pearl millet), foxtail millet via zoospores entering roots/stomata. Systemic spread causes chlorosis, stunting, and green ears (phyllody-like).

Disease Symptoms

Early: Yellow streaks on leaves, white downy growth abaxial. Systemic: Green ear disease with leafy panicles, no grains; leaf cracking in foxtail millet. Oospores overwinter in seeds/crop residue.

Management Strategies

Use resistant hybrids (e.g., HB3), metalaxyl seed treatment, crop rotation, rogue infected plants. Early sowing avoids peak sporulation.

Economic Impact

Causes 20-50% yield loss in millets; green ear disease reduces fodder/grain in India/Africa.