एक पादप रोग जो एक बड़े भौगोलिक क्षेत्र में तेजी से और आक्रामक रूप से फैलता है, तथा कम अवधि में पौधों की आबादी के एक बड़े हिस्से को प्रभावित करता है, क्या कहलाता है?

Which of the following is the most common symptom of viral diseases in plants?

As per the prediction model for Indian stem rust disease, what will occur if the following conditions are met? 1. 5-6 infection sites are observed within 25 ± 5 km around January 15-20 in UP and North Bihar. 2. Rain amount and rainy days over Northwest India from January to mid-April are twice the normal level.