Water

• Italian stone pines are fairly tolerant of drought, once they’ve been established, but a lack of water can cause them to wilt, and their needles may turn yellow and fall off. Water trees infrequently but deeply, soaking the soil to a depth of 8 inches. Don’t water near the trunk, because water on the tree will encourage fungal diseases. Add water near the drip line.
  
  

Frost

• Italian stone pines aren’t cold-hardy, and frost damage can cause their flowers and shoots to wilt and turn black. Watering your tree before a freeze may help protect it, because the added moisture will increase the ground’s ability to hold heat. Cover your tree with a blanket at night to protect it from freezing temperatures. Christmas tree lights in the branches can produce enough heat to keep your tree from freezing, especially if it’s covered. Protect the roots by covering the ground with at least 2 inches of mulch.
  
  

Phytophthora

• Phytophthora root rot is a fungal infection that causes trees to turn yellow and wilt, lose their needles and suddenly die. Roots of infected trees are usually brown or black, rotting, with heavy pitch oozing from them. Stressed trees are more prone to infection. Zoospores, fungal spores capable of swimming through water, invade Italian stone pines through their roots or lower trunks. Phytophthora isn’t usually a problem for pines growing in well-drained soil. Improve drainage and drench soil with fungicides to control this disease.
  
  

Pine Wilt Nematode

• Italian stone pines are resistant to the pine wilt nematode, but it is possible for them to develop this disease, which is spread when long-horned cerambycid beetles carry nematodes from tree to tree. Needles on infected trees turn yellow and brown. Infected trees also have reduced resin production, which you can see when you cut a branch open for examination. Infected trees wilt and die in a single season. The nematode can be identified only by examining a piece of the sapwood under a microscope. There is no cure; you must remove and destroy infected trees.
  
  

Pine Pitch Canker

• Although Italian stone pines are usually resistant to pine pitch canker, they can become infected with this fungus, which is spread by several species of beetles. The cankers that form on the trunks, branches and exposed roots restrict the flow of water through the tree and cause the tips of infected branches to wilt. Needles turn yellow, then red, and fall off the tree. If several branches are infected, the crown may die back and the entire tree can die. Infected trees produce large amounts of pitch that can cover the bark for several feet. Peeling back the bark near a lesion will reveal honey-colored wood that’s soaked with pitch. Even severely diseased trees can recover from pine pitch canker, so delay cutting down infected trees unless they become a hazard. Pruning doesn’t slow down this disease, but it can improve the looks of your tree.