Issue: July 14, 1997
Brown needles on pine treesQuestion:
The pine trees around Raton are turning brown and a lot of them are dropping their needles. Usually only part of the tree is turning brown, one side or the bottom. In the other part of the tree the needles look okay. What is wrong? Do I need to do something to save my trees?Answer:
I have seen these trees in Raton, in the Jemez Mountains, and I understand the same problem is occurring near Cloudcroft. Dr. Natalie Goldberg, NMSU Cooperative Extension Service Plant Pathologist, is in the process of determining which of several fungi are responsible for this needle cast in our pine trees. While brown needles due to environmental conditions are common in New Mexico, we do periodically find disease outbreaks which also cause browning of needles. The diseases appear after unusually moist periods, such as we experienced this spring. Weak trees may succumb to this disease, but healthier trees should recover. Once Dr. Goldberg identifies the disease organism responsible for the problem this year, she will notify County Extension Agents around the state with the appropriate control methods.
In the forest the weaker trees will succumb and make room for younger trees. In landscapes we may be more concerned with preserving our trees. If you are observing considerable needle browning in your landscape pine trees, contact your County Extension Agent for details regarding treatment. It may be a couple of weeks before the disease organism is identified and appropriate treatment determined.
In the meantime, be watching for signs of pine bark beetle activity. Bark beetles can quickly kill trees weakened by drought, disease, or improper cultural practices. Signs of bark beetle infestation include pitch tubes formed on the trunks of the trees and collection of sawdust on the bark, branches, and the ground below the trees. Once the trees have been infested, removal is the best treatment to prevent the spread of bark beetles to nearby healthy trees. The removed trees may be saved for firewood, but to prevent the spread of the beetle, this firewood should be stacked in piles no more than 4x4x4 feet in a sunny location and covered with clear plastic. The clear plastic should be sealed around the base of the pile with soil. This contains the insects and kills them as the plastic retains heat around the woodpile. This procedure should be practiced any time there is green firewood stacked near standing trees.
Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: firstname.lastname@example.org, office: 505-865-7340, ext. 113.
Please copy your County Extension Agent and indicate your county of residence when you submit your question!www