Q: I was at the garden this morning and noticed how droopy our patch of sunflowers is!Β So I took a closer look and discovered that the leaves are infested with insects! There are little white aphid looking things, and then massive sections of black dot-looking bugs, especially underneath the leaves. Maybe you can tell from the photos Iβve attached. I did my best to give them a sudsing with Dawn. Do you think this is the remedy for these bugs? Any other thoughts?
A:Β The insects on your sunflowers are called lace bugs, not to be confused with lacewings, which are beneficial predators. The black spots are likely a combination of young lace bugs, which are that color, and their poop.
Lace bugs are of the true bug order we call Hemiptera and they have piercing-sucking mouthparts just like the aphids. So they suck out the sap rather than chewing the foliage. The result of large numbers of these lace bugs feeding over a period of weeks is discoloration and the droopy look you noticed.
Fortunately, they donβt damage the flowers as much as the leaves. Insecticidal soap is a good solution as is a blast from a hose. Some dish soaps are toxic to plants so if you donβt want to spend a bit more for actual insecticidal soap, you might try spraying only part of your plant to begin just in case. These insects tend to be on the underside of the leaves at least as much as we see them on the tops so make sure you spray the plants in such a way as to cover the underside of the leaves.
Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu
