Sweet potato scab
Small corky brown scabs form on leaf veins and vines, and young leaves curl, twist and stay small.
Crops it strikes
What you see
When to act
In wet weather check young leaves and vine tips every week for small, raised, corky spots and puckered, curled leaves. Pull the first sick hills. A spray pays only in a nursery where you cut planting vines.
What to spray
Active ingredients only, never brands. The FRAC group tells how it works: switch to a different group next time, so the disease does not learn to survive it. Spray only when the damage is worth the cost, and only with products registered with the Fertilizer and Pesticide Authority for your crop. Follow the label. The Shopee and Lazada links only show who sells something with that active ingredient, not a recommendation of any seller or product.
On labels for it, but not advised
- Maneb: No maneb product is on the Philippine list. Use mancozeb instead.
How to prevent it
- Plant a scab resistant variety. It is the main answer in wet, upland areas.
- Take cuttings only from healthy, scab free fields, and use the young tip cuttings.
- Rotate with other crops and do not plant beside an older field with scab.
- Remove and bury old vines after harvest.
Where this comes from
Not sure it is this one?
Many diseases look alike. Send a photo to Anee, the smart farm technician in anee.io. She reads it with your crop, its age and the weather, and tells you what it most likely is and what to do first. In Tagalog or English.