Trees may seem impervious to things that might bother smaller plants, but in reality, they are just as susceptible to pests and disease as any other growing thing. If you allow an infection or infestation to run unchecked in your tree, you could end up with a serious problem or even a dead tree on your hands. Fortunately, it is fairly simple to give your tree the basic help it needs to fight disease and insects in the form of some easy tree pest and disease control.
Tree pest and disease control involves not only preventing diseases and pest infestation, but also helping your tree conquer these problems if they are already in place. The point of controlling the infection is to give the tree time to overcome the disease and to keep it from spreading to other parts of the tree that have not yet been impacted or other trees in the yard.
Sterile pruning will be a part of your basic tree pest and disease control process. In many cases, simply removing diseased leaves or even limbs of a tree can help it overcome an infection on its own. For example, if the leaves on one limb are displaying spots, have yellowed early or appear to be stunted or distorted, then you may need to remove that limb to prevent the spread of the infection. Sterilize your clippers with rubbing alcohol, and resterilize them after each cut. Cankers can also be removed in this manner, but you should wait until winter to do so since they are less likely to reinfect the tree during cold weather.
Ground and Yard Maintenance
If you have a tree that has a fungal infection or if you just want to prevent your tree from developing this problem, keep the area under the tree clear of plant debris. This means remove leaves, branches and shoots regularly. Dispose of the plant material by burning or in sealed plastic bags. Many types of fungi grow underneath trees and then infect the plant when rain splashes spores onto the plant. Keeping the area beneath the tree clear will help keep your tree from catching such an infection.
The way that you water your tree will go a long way toward keeping it free of infections. Water using a drip hose if your tree actually needs to be watered. In most cases, unless you are dealing with drought conditions, mature trees will not need watering. Make sure that you do not allow sprinklers to wet the tree's leaves, and only water in early morning to discourage mold and mildew.
If you have problems with bugs, you may treat your tree with natural or chemical pesticides. Natural, organic options include neem oil or a mild dish-soap-and-water mixture. Both of these options will kill existing pests and prevent new arrivals from settling in. Coat both the top and the bottom of the leaves. If you wish to use chemical alternatives, check with a local professional, since not all pesticides are considered legal or safe in all areas of the country.