Nigeria produces most of the world's yam. Anthracnose on the vine and rot in storage are the two losses that matter, and both start with the quality of the seed tuber.
- Grown in
- Nigeria, Ghana, Benin, Côte d'Ivoire
- Season
- 7–11 months
- Soil & pH
- Deep, friable, well-drained soil, pH 5.5–6.5
What to scout for on Yam
- Dark sunken leaf and vine lesions — yam anthracnose
- Soft wet rot in stored tubers
- Mosaic mottling from yam mosaic virus in the seed stock
- Nematode galling on the tuber surface
Diseases that attack Yam
Products you can buy for Yam
Typical registered products for the diseases above, with active ingredient, mixing rate, spray interval and pre-harvest interval. Rotate FRAC/IRAC groups to avoid resistance.
Imidacloprid 17.8% SL (vector control)
Active ingredient: Imidacloprid
- Dose:
- 0.3 ml per litre foliar, or 1 ml/L as a nursery drench
- Interval:
- Every 14–21 days, maximum 2 per season
- PHI:
- 21 days
Targets the aphid and whitefly vectors, not the virus. Avoid during flowering to protect pollinators.
Mineral / horticultural oil
Active ingredient: Paraffinic oil 80%
- Dose:
- 10 ml per litre (1% v/v)
- Interval:
- Every 7 days during vector flights
- PHI:
- 0 days
Oil films block non-persistent virus transmission on the aphid stylet — one of the few tools that reduce spread.
Skimmed milk protein spray
Active ingredient: Milk protein 10% solution
- Dose:
- 100 ml skimmed milk per litre of water
- Interval:
- Before handling plants and weekly during transplanting
- PHI:
- 0 days
A proven low-cost barrier against mechanical transmission of tobamoviruses on hands and tools.
Certified virus-free planting material
Active ingredient: Clean seed / clean cuttings
- Dose:
- 100% of planting material
- Interval:
- Every planting
- PHI:
- Not applicable
There is no chemical cure for a mosaic virus. Clean stock plus resistant varieties is the whole strategy.
Chlorothalonil 75% WP
Active ingredient: Chlorothalonil
- Dose:
- 2 g per litre (1.5–2 kg/ha)
- Interval:
- Every 7–10 days
- PHI:
- 7 days
Backbone protectant for Septoria and Cercospora leaf spots. Full leaf coverage, including undersides, is essential.
Mancozeb 80% WP
Active ingredient: Mancozeb
- Dose:
- 2.5 g per litre
- Interval:
- Every 7 days
- PHI:
- 7 days
Adds zinc and manganese nutrition alongside disease control.
Doses shown are typical registered field rates. Always read the product label, confirm the product is registered for your crop and country, respect the pre-harvest interval (PHI), and wear the protective equipment the label specifies. PlantWatch AI provides agronomic guidance, not a legal spray recommendation.
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