Plant Diseases/Spider Mites on Butterfly Bushes
Hello, Dr. Vann. Thanks for answering my question. I have two Black Knight Butterfly Bushes that are infested with spider mites. This is the second year this has happened. I tried spraying them with a broad use insecticide, but since the spider mites are on the underside of the leaves and the bushes are so large it is very difficult to get them all with the foliar spray. I thought about using a systemic insecticide to get rid of the spider mites, but I was concerned that the systemic would also kill the butterflies and bees that come to sip the flowers’ nectar. Do you know if a systemic insecticide would kill the insects drinking the flower nectar or would it not affect them? Please let me know. I would appreciate it.
This would be a better question for an entomologist or someone with more insect knowledge than myself. You may consider visiting with your local garden center/nursery for this advice. Some folks do have some luck with using a high pressure stream of water to "wash" these nasty critters off the plant.
You can also contact your local county Agricultural Extension office also. There is usually an office in the county courthouse building in every county.