Crop rotation reduces disease pressure primarily by preventing pathogen buildup in soil or crop debris; which condition ensures effectiveness?

Crop rotation reduces disease pressure primarily by preventing pathogen buildup in soil or crop debris; which condition ensures effectiveness?

• A. Spores blow in from distant fields
• B. The pathogen survives locally in soil or crop debris
• C. The disease is caused by a virus
• D. The disease has a very wide host range

Answer: (B)

Crop rotation works by cutting off the pathogen’s ability to build up on the same field year after year and by reducing the amount of infectious material left in soil or crop debris. For this to effectively lower disease pressure, the pathogen must survive locally in the soil or debris between crops. When it does persist in that local reservoir, rotating to nonhost crops over time reduces inoculum and lowers disease risk in subsequent plantings. If inoculum mainly comes from outside the field (not from local soil or debris), or if the disease is caused by a virus or has many hosts, rotation won’t reduce local inoculum as effectively, so its impact is limited. Therefore, the key condition is that the pathogen survives locally in soil or crop debris.

Crop rotation works by cutting off the pathogen’s ability to build up on the same field year after year and by reducing the amount of infectious material left in soil or crop debris. For this to effectively lower disease pressure, the pathogen must survive locally in the soil or debris between crops. When it does persist in that local reservoir, rotating to nonhost crops over time reduces inoculum and lowers disease risk in subsequent plantings. If inoculum mainly comes from outside the field (not from local soil or debris), or if the disease is caused by a virus or has many hosts, rotation won’t reduce local inoculum as effectively, so its impact is limited. Therefore, the key condition is that the pathogen survives locally in soil or crop debris.