The Pine genus features over 100 species of coniferous trees that are relatively lenient to poor soils and drought conditions. With two subgenera, Pinus and Strobus, these trees range in size from small shrubs to massive, pyramidal uprights that easily reach heights of 100 feet. Though these trees are mostly tolerant, pine trees are susceptible to pest infestations and diseases.
Armillaria Root Rot
Armillaria root rot is a fungal disease that originates on tree stumps. This fungal disease spreads down through the decaying stump and into the soil. The armillaria fungus then spreads through the soil into the roots of weakened pine trees. Infected pine trees develop a weakened root system which results in growth stunt and needle discoloration. The infected pine will also develop a mat of white fungus between the bark and the wood and fungal mushrooms will grow around the trunk of the tree. There is no cure for armillaria root rot. The disease can be prevented by removing all surrounding stumps and roots from the area, and by providing your pine with generous amounts of water and fertilizer.
Pine Needle Scale
Pine needle scale is an insect infestation that can result in the death of your pine tree, if left untreated. This insect thrives from eggs that are laid in the late summer and hatched in the spring. The newly hatched insects initially appear as bright red. As they age, these insects appear as a white and even clear with yellowish spots and a waxy covering. These scale insects feed on the water and nutrients found within the needles, which results in the discoloration and wilt of the pine. Severe infestations will result in heavy defoliation and death of your pine tree. Chemical insecticides are effective in treating the infestation if it is applied prior to the scale's development on the waxy outer covering.
Phytophthora Root Rot
Phytophthora root rot is a soil-borne fungal disease that infects the pine through its root system. Pine trees are most susceptible to this disease when it is drought stressed. This fungus diminishes the root system's ability to pass nutrients and water throughout the tree. As a result, the infected pine tree suffers from wilt, growth stunt, dieback and defoliation. There is no fungicidal treatment that will cure this disease. However, a vigorously growing, well-watered pine tree that receives regular fungicidal treatments can live with the disease.