A turkish pine (Pinus brutia) and a Chinese white pine (Pinus armandii) were recently removed from the Canal Reserve area near the Museum of History and Industry. Both trees declined suddenly over the past year and died over the winter. Blue staining was evident in the wood of both trees. We’re not sure exactly how these trees are infected with the fungus, but one theory is that a bark boring insect (red turpentine beetle) carries the pathogen into the tree. These beetles appear to be secondary pests, meaning they attack stressed trees. The beetles lay eggs in galleries under the bark and the larvae overwinter in these galleries. The new generation of beetles emerges in warm weather the following spring.
Because these insect pests are secondary, management of our pine collection is focused on alleviating stress through deep root aeration, compost and mulch applications. Dead or severely declining trees are removed and the wood and brush are destroyed immediately to stop the spread of beetle. Persistent monitoring helps staff prioritize which trees need the most help. Over time, we should be able to minimize losses to the collection and keep our remaining pines healthy.