While insects are an important food supply for the local bird population, the birds never seem to eat enough of them. Insect pests are one of the most common issues that plague deciduous trees.
Some insects are species specific, such as the sycamore lace bug. Others chew on anything from the stately elm lining the street, to the poplar forming a windbreak or maple tree adding brilliant color to the autumn landscape. Some insects bore into the tree, cutting off the tree’s circulatory system. Others just suck away somewhat symbiotically, gradually draining away the tree’s life forces.
Insects sometimes make their presence known through dramatic displays of webs. You may wonder if those webs in your tree are something to worry about. When it comes to preventative tree care, should you be concerned about insects stripping your trees of leaves?
The answer is, “It depends.” While in most cases, insect defoliation is a cosmetic yet not life-threatening to your deciduous trees, it should never be ignored. A mild infestation ignored this year will become an even heavier influx next year. It doesn’t take long for a particular insect to become a plague. Some insects may even become a serious nuisance in your home as well as in your trees.
Consider the sycamore lace bug. It rarely causes serious damage, yet when populations get out of control it can stunt the growth of the tree. You’ll find adults and nymphs sucking plant juices from the tree on the underside of the leaf. They do have natural enemies, so using pesticides should be a last resort for a severe infestation. Sometimes a simple solution is available. For example, a strong spray of water is often adequate to dislodge the bugs.
Many of the most destructive insects are only seen through close inspection. This means many trees go into decline with hardly a warning. This is because the type of damage caused by different classes of insect pests varies. For example, leaf feeding insects cause less damage than boring insects which prefer to eat directly upon the tree’s nutrient carrying layers, the cambium and xylem. This often kills the tree within a season or two.
Early detection of tree boring insects is vital. If you have aspen, cottonwood, willow, birch or ash trees on your property, having a certified arborist inspect your trees for the signs of borer activity is a wise investment. If these signs are discovered, the arborist can help you set up an integrated pest management plan that is kind to the environment while preserving the health of your trees.
Because treatment must be matched to the type of insect, the best results are obtained by working with a certified arborist. These professionals also help you identify factors that could be putting your trees at risk for insect infestation such as poor drainage, inappropriate mulching or failure to prune appropriately.