My cassava plants here in Beni Bolivia had been thriving. However, more recently, I have noticed the leaves start to look strange. Some of them have become deformed and/or discolored. My research hasn’t seemed to indicate a disease but potentially a watering problem or nutrient deficiency. If anyone can identify what may be going on from the picture, please let me know.
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Hi Ellie,
It appears that the leaf deformities are only on the new growth, is that correct?
I do see a leaf tissue gall on in the first photo on the left- are there more on the undersides of leaves? Leaf galls can be caused by a number of things (various insects, fungus, or bacteria) but location can tell us a bit. Do you see any pin-prick discolorations on the underside of the leaf? This would indicate a piercing-sucking insect.
Plant leaves curl in response to various environmental stressors. When certain pests, such as psyllids, mealybugs, and thrips, feed on a leaf it can cause leaf curling and deformation (see below). When plants are too hot or too dry, they can also curl along the entire leaf margin. Some diseases, usually viral, also cause leaf curling. Below are some general guidelines:
- Leaf margins curling down, no yellowing – underwatering
- Leaf margins curling down, yellowing – overwatering
- Leaf margins curling upwards – heat or wind stress
- Leaf curling mainly in new growth and in deformed ways – often a disease or insect pest
- Middle or old leaves curling and have patchy yellowing but green veins – Magnesium deficiency
- New leaves curling and have patchy yellowing but green veins – Manganese deficiency
From the photo alone, it’s hard to tell which of these you may be experiencing, but if you can answer my questions above it might rule out a few things. My honest first reaction was that it looks viral, but I don’t know the viral diseases of South America very well. I found one paper I have requested that lists some.