Question: I have some violets as well as a few orchids. My problem is aphids, which I think came in on some mini roses from a local nursery. I’d like to get some more violets, but I’d like to get rid of this problem first.
Answer: Aphids aren’t usually a common problem in violets, though they have been known to appear in a collection on a rare occasion, usually when brought in on another plant. They are usually light green, sometimes black, and have soft, pear-shaped bodies that are easily visible to the naked eye. They usually can be seen on the undersides of leaves or on blossom stems, where the plant tissue is softer and more vulnerable. Because they are easily visible, they can usually be easily eliminated with quick treatment of the affected plants.
Only twice (in over 25 years) have we found aphids in our violet collection. In one instance, they came in on some newly acquired orchids and were quickly eliminated by spraying the affected plants with Knox-Outat the recommended dilution. One thorough spraying did the trick. There are a number of insecticides that can be effective on aphids–malathion, diazanon, or many pyrethrin spays. As always with such chemicals,read the label, and follow all of the usual precautions to protect yourself from exposure. In the second instance, we found large numbers of aphids on a number of Streptocarpus plants that we had purchased at a show. In this case, the numbers were too many, and the plants not valuable enough, so we simply tossed all of the affected plants into the compost pile. They could have been saved, but doing so wasn’t worth the time and wasn’t worth the risk to our health.