What is this infestation?

Question

My potted carambola (startfruit) has started losing leaves recently, and when I looked very closely, I saw what I think is evidence of some sort of infestation. I have some insecticidal soap (Safer's, contains 50.5% potassium salts of fatty acids) that says it's good for aphids, spider mites, whitely, scale, psyllids, and slugs. I'm not sure what infestation I have so I don't know if I should just spray it on and hope it works, or should I look for something else.

There are two aspects to the infestation: One can be described as a sort of "webbing" of silk very close to the stems and leaves, with tiny dots (probably the insects themselves).

The other is very small dots on the leaves. They are smaller than the aphids I usually see, and they don't brush off as easily as aphids seem to.

Does anyone have an idea about what this infestation might be? Do you think the insecticidal soap will help save my carambola?

Answer 1

Spider mites, and lots of them! You can see the adults pottering around and the webs where they have done some renovations. On the leaves you can see the lighter dots where the juices have been sucked out of the leaf.

There a few ways to control this:

1. tough love: cut the whole plant down to the ground, dispose of infected stems, reduce water and wait for new growth, treat with soap and water if the problem returns
2. 5 ml dish soap in 1 liter of water or insecticidal soap, agitate, take a rag or cloth and wipe every leaf, top and bottom. Hose the solution off after a few minutes. Repeat at five to six intervals at least three times.

You should also check other nearby plants for spider mites as they can move around when there is population pressure.

Good conditions for spider mites are plants that are in hot and dry conditions and little exposure to their natural predators such as ladybugs. You might be able to change how attractive the plant is by moving it.