Bugs are on the move. You never know where they will show up next.
Q. I hope you will have an answer about what has happened to my coreopsis. I had two 10-inch-tall Jethro Tull coreopsis plants in a flower garden in my front yard, and was happy to see they were beginning to bloom when I cleaned out the weeds and some dried-up daffodil leaves last Tuesday. By Thursday afternoon, the coreopsis blooms were gone and the stems were covered with tiny, brown, oval-shaped bugs I have never seen before. These bugs were all over the stems and leaves! I have had flowers in my yard for several years with no problems. Have you ever heard of this? I am afraid to plant anything in this garden now, for fear that they will be infested as these flowers were. — V.G., Lynchburg
A. An insect called coreopsis leaf beetle is probably what devoured your Jethro Tulls. With its limited range of host plants, there is little chance of coreopsis leaf beetle attacking any of your other flowers.
Q. Could you tell me the best way to prune lilac bushes and also the preferred pruning time? In addition, I need to know what to do for an azalea bush that blooms but the leaves are looking like they are brown with white ash on them. It doesn’t affect the beauty of the blooms but it does look sad for leaves. Will this kill the bush or will it get better next year? What can be done to correct this? — P.B., Lynchburg
A. May and June are the best months for pruning lilacs. You may begin the job by cutting out a couple of the oldest trunks at ground level. The others can be cut back to varying heights if you want to keep the plant at a certain size. Most of the tiny suckers sprouting from the soil are best eliminated.
Your description of the azaleas suggests an infestation of azalea lace bugs. They will not kill your plants, and you can just ignore them if having off-color azaleas is OK with you. Natural control is provided by lady bugs, lace bugs, spiders and assassin bugs. You can also spray every three weeks with neem oil, soybean oil or insecticidal soap, or resort to more toxic products such as Sevin and Malathion.
Q. We noticed last week that a few of our Knockout rose bushes seem to be suffering. We have eight of them along a wall and looking at the leaves, they all have white spots on them to varying degrees. I tried to research online, but we don’t know if it’s a bug, blight or fungus. I have included a photo. — M.H., Lynchburg
A. You have an insect larva called rose slug. Insecticides such as Sevin work on it, and spraying the rose bush with a forceful blast of water from your garden hose also helps get rid of rose slugs.
Don Davis is a retired Virginia Cooperative Extension agent. He can be reached at firstname.lastname@example.org.