Tree Pests

• Commercially sold pesticides are always approved for use against one specific pest species or a range of them, so the first step in choosing the right pesticide for you trees is to identify the species damaging your trees. Tree pests are categorized primarily according to the kind of damage they inflict on the tree. Borer insects are those that "bore" holes into woody parts of trees by eating their way through tree bark and branches. Leaf-sucking insects are those that use their mouthparts to extract juices from the insides of tree leaves. Leaf-curling insects are those that cause feeding damage that results in leaves curling and wilting around the edges. Within each of these categories, there are numerous specific species of insect, and identifying the specific species of insect is key to choosing the right pesticide chemical.
  
  

Pesticide Chemicals

• There are numerous pesticide chemicals that are recommended for use on trees, many of which would likely be familiar to anyone who has battled insect pests on garden plants. It is important to emphasize that each of these chemicals is recommended for one specific species of insect (see Reference section), and choosing the wrong insecticide chemical for the pest that is attacking your tree will provide little or no control of that pest.
  
  

Pesticide Types

• A secondary though just as important consideration to make when choosing a pesticide chemical is the mode of action of the particular pesticide. Some pesticides, such as dormant oils, are applied to trees to prevent a pest infestation before it actually occurs. Other pesticides are considered "rescue treatments" that are only applied to a tree once an infestation has been observed on that tree. Within this latter category, there are two types of pesticide -- synthetic and organic. Organic compounds such as neem oil and horticultural oil are derived from natural sources, while synthetic pesticides are synthesized.
  
  

Integrated Pest Management

• Tree experts are nearly unanimous in recommending an integrated approach to pest management in trees. Selecting pest-resistant tree cultivars can go a long way in preventing a pest problem from ever occurring. Tree pests tend to only attack those trees that are already in a declining state of health, so pruning your trees to allow for proper air circulation and supplying the trees with sufficient moisture and nutrients can keep insects away from your trees. If use of a pesticide is warranted, choose one that is safe for outdoor use on the trees you are growing and that is targeted at the specific insect species that is attacking your tree (see Reference section). Always follow printed application instructions exactly.