Q. One day I was at a local water plant supplier and I saw that they have the same problem as me with their plants: aphids. We both have little black bugs speckled all over our water lettuce and water lilies. I asked what these bugs were and they said aphids, but they did not know how to get rid of them.
These little bugs have complete control of my plants and they make my pond look ugly. None of the methods commonly used to control aphids would be safe for use in my pond.
A. Yes, the black bugs are aphids, and they are easily transported on aquatic plants. These little aphids are called blackfly aphids. They can be controlled by simple hosing once or twice a day. A good strong spray across and under leaf surfaces will knock them into the pond. Having a few insectivorous fish, such as mosquito fish or orfes, will help because they will eat the aphids in the water.
This approach also has the effect of adding fresh water to the pond, aerating the water surface, clearing plant leaves of dust, and is also completely non-toxic. In addition, it gets you out to the pond once a day to see what is going on. No insecticides are safe for use on the pond.
These particular aphids apparently spend the cooler winter months on cherry trees and plum trees. So, if you have some in your garden you might consider using an oil spray over the winter to reduce the population. Just do not spray near the pond.