Explore common diseases affecting coriander crops, focusing on root and soil-borne fungal threats in horticultural agriculture. Enhance your crop health knowledge with accurate facts and examples.
Which fungus is most commonly responsible for damping off disease in young coriander seedlings grown in moist soil conditions?
Explanation: Pythium spp. is a soil-borne fungus known for causing damping off, particularly in seedlings in overly moist conditions. Alternaria alternata typically causes leaf spots, not seedling death. Erysiphe polygoni is responsible for powdery mildew. Fusarium graminearum mainly infects cereals, not coriander.
If you notice a white, powdery coating on the leaves and stems of coriander plants, which disease is most likely present?
Explanation: Powdery mildew is characterized by white, powdery fungal growth, particularly on leaves and stems. Root rot affects below-ground parts with browning and wilting, not a white coating. Downy mildew produces yellowish or downy spots, not powdery patches. Bacterial leaf blight presents as water-soaked or brown spots, not a white residue.
A coriander farmer observes yellowing leaves and stunted growth, with roots appearing brown and decayed; what is the most likely disease?
Explanation: Root rot leads to brown, decaying roots and poor plant growth due to fungal pathogens in the soil. Powdery mildew appears as a white residue on aerial parts, not roots. Alternaria leaf spot affects foliage, not roots, while aphid infestations cause sap loss and distortion, but not brown, decayed roots.
Which environmental condition most favors the development of downy mildew in coriander fields?
Explanation: Cool, wet weather creates ideal conditions for downy mildew, as the pathogen thrives with high humidity and low temperatures. Hot, dry weather is unfavorable for downy mildew but may suit some pests. Sandy, low-moisture soils inhibit the disease's spread, and soil pH alone does not directly favor downy mildew development.
Which visual symptom is most closely associated with Alternaria leaf spot on coriander leaves?
Explanation: Alternaria leaf spot manifests as dark, circular lesions with concentric rings on coriander leaves. Powdery white spots are typical of powdery mildew. Brown, mushy roots are a symptom of root rot. Wilting without visible leaf lesions is not a key sign of Alternaria infection.