I saw this yesterday, and only spotted it due to the ants that gave them away.
The cuttings that I took last year from the currant bushes had lots of ants crawling over them. I thought this was curious, as ants will rarely attack a plant or food. Then I noticed that each of them kept stopping at the same points along the stem of the plant.
On very close inspection I saw what looked like individual scales.
At first I thought it may be aphids, as they can produce a honeydew when feeding off the plants sap, which attracts ants. But I noticed that these creatures didn’t appear to have the long legs that aphids do, or even a distinct head. There are certain species of scale insect that produce the honeydew. It’s thought that the ants will act as a security measure for the scale insects, working for both sides – you protect us, we will feed you a sugary high-energy food.
If left unattended, these insects can cause a build-up of a ‘sooty mould’ and may severely damage a plant. Some species will not affect the plants growth, but as these are on young cuttings, I have decided to scrape them off and kill them. The only organic way of eradicating these is by keeping an eye out for them. Fortunately, I just need to watch the ants, and see where they stop to give the scale insect position away.
Originally posted 2018-04-10 07:38:34.