Identifying problems with pines

Pines often provide a backbone to a home landscape. They are a constant presence through all seasons providing shade, shelter from the wind and rugged beauty. Usually pines are maintenance free - give them the water they need and they seem to thrive with a little minor pruning now and again.

Too often, homeowners take pines for granted. I have even heard people say, "Well, they have been there so long, I figured their roots were in the water table, so I stopped watering." Rarely can pine or other tree roots reach the water table or survive on natural precipitation. This is particularly true for ornamental pines. If you look around northern Nevada the only native pines you see growing in the valleys are pinyon. Jeffrey and ponderosa pines grow in the mountains or canyons, but rarely east of the Carson Range; the conditions are not ideal for them.

Native pines thrive with rain and snow in fall, winter and spring, and minimal summer water. Ornamental pines, such as the commonly used Austrian pine, must have sufficient supplemental water during the dry months. Trees, both native and ornamental, that do not receive enough water become stressed and susceptible to beetles, borers and other insects.

Gail Durham, the Nevada Division of Forestry forest health specialist, flies all over Nevada each year mapping insect infestations in native trees. This past year she flew 700,000 acres. She said there were outbreaks of pine scale, sawfly, adelgids and black needle scale. She has recorded California flathead borer on Jeffrey pines along the east front of the Carson range in west Washoe Valley and around Jobs Peak in Douglas County. She says that pine scale is being found on ornamental pines too.

If you find an insect problem in your pines, get the insect identified. Bring insect samples to your local Cooperative Extension office. If we can't identify them, we will take them to the state entomologist. Once we know what the pest is, we can advise a management strategy. Avoid pruning pines and other evergreens in the summer or early fall. Pruning cuts attract beetles and borers. Prune only in late fall and winter when the insects are less active. Ideally, cut branches should be removed from the property. Chipping is a satisfactory method of disposal. Keep chips away from live trees; they can attract more bark beetles. More information on pines, especially pinyon pines, at unce.unr.edu/publications/files/nr/2003/EB0302.pdf

JoAnne Skelly is the Carson City/Storey County Extension educator for University of Nevada Cooperative Extension and may be reached at skellyj@unce.unr.edu or 887-2252.