To avoid malnutrition, be sure to give your trees an adequate amount of micronutrients, such as magnesium sulfate, limestone, gypsum, iron, and zinc. However, trees need very limited amounts of these compounds, and an overabundance can be harmful. Have a certified arborist advise you on the correct amounts of each you should provide.
Borer insects are very hard to anticipate or eliminate. The best defense is simply maintaining your tree’s general health so it can bounce back if it does develop an infestation.
Additionally, frequent watering and fertilization in anticipation of a cold night can also “harden” the cells of certain plants.
Over watering or poor drainage can cause root rot in your trees. Fungicides or manganese treatments can be effective as treatments or preventative measures.