In Virginia, we often notice several common issues involving your plant material during the summer. In most cases, these issues are already present but become more prevalent during the summer due to heat stress. In the image below, you’ll see lace bug damage on the underside of plant leaf. Lace bugs are very small insects, measuring only about 1/8 inch long, however they can cause considerable damage to the foliage of ornamental shrubs and trees. Boxwoods are also susceptible to pest damage in the summer, as shown in the image below on the right. This is leaf miner damage, caused by an orange-yellow mosquito-like fly. Leaf miners swarm around boxwoods in mid to late April for about two weeks, when they mate and lay their eggs into the boxwoods’ leaves.
Fungus can cause your trees and shrubs to defoliate early, amplified by stress from the summer heat. If you notice the leaves of your plants turning black, this is likely due to the presence of scale insects. They suck the sap from plant leaves, turning them black with a fungus called sooty mold. Similarly, gloomy scale on the bark of a tree, also turns into sooty mold. Powdery mildew is another form of fungus disease that plants can fall victim to, as pictured below.
Premature defoliation doesn’t typically kill trees, but if it happens year after year, it is likely to weaken the tree, reducing the likelihood of survival. Mulching and deep watering help keep trees less stressed in dry years, but if you are noticing any of these issues, please contact us! Virginia Green’s Tree and Shrub program can take care of it for you.