There are several reasons why a pine tree can become sick. It could become infested with insects, such as southern pine beetle, European pine sawfly, spruce spider mite, white pine weevil, western pine beetle or mountain pine beetle. It may also develop pine needle scale, which causes white scales to cover pine needles, leading to their death. Depending on the type of illness, it can take up to one year for a pine tree to die. In many cases, people don't notice their tree is sick until it's too late.
Look over the pine tree for disease or insect infestation. Take note of green needles that have turned brown, which points to the likelihood that they will die soon. Also notice white scales, which indicate pine needle scale.
Examine the base of the pine tree for sawdust. This indicates that the tree might be infested with pine borer or other insects.
Climb up the tree and saw off branches and limbs that appear to be sick. Cut the diseased wood off where it meets healthy branches.
Apply a crawler spray and/or insecticides to cure sick pine trees that have pine needle scale. Apply a series of two to three crawler sprays every seven days between May and July. Insecticides can be applied after the crawlers settle in June and August. Follow manufacturer's instructions.
Cut down on the risk of western and mountain pine beetle attacks by keeping pine trees from getting bruised. The wounds open the bark up to infestation.
Remove all vegetation, including weeds and grasses, from the base of pine trees. Keeping their root zones clear will help keep insects away.
Use an insecticide that targets borers. Most are applied as sprays to branches and pine tree trunks. They will not kill larvae that are already living in the tree but will target those that are tunneling through the bark. Follow the manufacturer's application instructions.