Explore the key diseases affecting coriander crops and the best practices for their identification and management. This quiz covers common pathogens, symptoms, preventive measures, and their agricultural impact.
Which symptom most commonly indicates powdery mildew infection on coriander plants?
Explanation: Powdery mildew typically appears as white, powdery growth on aerial plant parts. Black streaks on seed pods are not characteristic of powdery mildew; these may suggest another fungal disease. Sunken, brown root lesions usually indicate root rot. Purple discoloration of flower buds is uncommon in powdery mildew and may result from unrelated causes.
A coriander field shows small, dark brown circular lesions with yellow halos on leaves. Which disease is most likely responsible?
Explanation: Alternaria blight is characterized by brown circular leaf spots with yellow halos. Stem gall causes swelling on stems, not leaf spots. Bacterial wilt mainly causes wilting without these distinctive lesions. Rust typically presents as orange to brown pustules rather than haloed spots.
Which of the following is a common source of primary infection for stem gall disease in coriander?
Explanation: Stem gall is often seed-borne, making contaminated seeds a primary source of infection. Aphids may transmit some diseases, but not stem gall. Irrigation water is more commonly associated with soil-borne or water-borne pathogens, while over-fertilization does not directly introduce pathogens.
What is an effective cultural practice to minimize the spread of coriander root rot?
Explanation: Crop rotation helps reduce soil-borne pathogen loads responsible for root rot. Planting in poorly drained soil and increasing humidity promote disease development. Delaying harvest time does not prevent disease occurrence and may worsen the problem.
Which disease can cause significant yield loss in coriander due to malformed stems and reduced seed quality?
Explanation: Stem gall leads to swollen, malformed stems and can sharply decrease seed production and quality. Leaf blistering is a minor issue and seldom affects yield significantly. Downy mildew primarily affects leaves, not stems. Charcoal rot typically damages roots or lower stems and is less likely to cause distinctive swollen galls.