Delve into the main root diseases affecting castor crops, their symptoms, management, and impact. Sharpen your agricultural understanding of castor root health challenges with scenario-based questions.
A farmer notices sudden yellowing and wilting of castor leaves, especially during the hot part of the day, but the plants do not recover after sunset. What disease is most likely responsible for these symptoms?
Explanation: Fusarium wilt is characterized by persistent wilting and yellowing that does not recover at night, common in castor fields. Powdery mildew and rust mainly affect the aerial parts with visible fungal growth or pustules, not wilting. Alternaria leaf spot causes round spots on leaves rather than wilting.
Heavy rainfall followed by poor drainage in a castor field can increase the risk of which common root disease?
Explanation: Rhizoctonia root rot thrives in wet, poorly drained soils, attacking roots and causing damping-off and root decay. Aphid infestation is an insect issue, not a fungal root rot. Cercospora blight and sooty mold cause leaf symptoms, not root disease.
Which pathogen, among these, primarily attacks the root system of castor plants leading to decay and plant death?
Explanation: Macrophomina phaseolina causes charcoal rot, severely affecting castor roots, especially under drought. Erysiphe cichoracearum causes powdery mildew on leaves, Colletotrichum capsici leads to stem or leaf spots, and Phytophthora infestans is mostly known for late blight in solanaceous crops.
What is an effective cultural practice to minimize the occurrence of root diseases in castor cultivation?
Explanation: Crop rotation reduces soil-borne pathogen buildup by alternating with non-host crops. Excessive nitrogen or late sowing can increase disease risk or stress plants. Monocropping promotes disease persistence by maintaining the host in the field.
If young castor seedlings suddenly collapse with dark lesions at the soil line after heavy rains, which early-stage root disease is indicated?
Explanation: Damping-off is common in seedlings, causing collapse at the soil line after wet conditions due to soil fungi. Bacterial leaf blight affects leaves, not roots. Virulence deficiency is not a disease. Sunscald causes stem browning due to excess heat, not pathogen attack.