Bronze Birch Borer

Bronze Birch Borer is a close relative to the emerald ash borer but it is host specific to birch trees. Its preferences are the Weeping European birch (Betula pendula), paper birch (Betula papyrifera) and river birch (Betula nigra). Birches make up 1-3% of the estimated tree population within Jamestown. The birches are very attractive trees with the white bark and the weeping branches of the European birch are an added attraction. Unfortunately they are the most susceptible and with age the trees are weakened and attacked by the borer. They attack the upper branches and the larvae borer around the branch and cuts off the vascular system to the upper parts of the tree causing a dieback in the canopy. The borer moves down the branches to the trunk and as with EAB it is almost too late to treat the tree. There are several insecticide treatments that can be used but they can be expensive and offer little hope.

Call the City Forester for updated information and advice on whether it is an advantage to treat your tree. Birch trees planted on the prairie have to put up with harsher conditions than their native sites. Birch like moisture but also require good drainage. The are native in sandy soils that have regular rainfall but do not become water logged like clay soils can become. The root system also has problems with uptake of micronutrients from our prairie soils. The soil ph can vary from 6.5-8.0 and sodium(Na) is presence and tends to tie up the micronutrients needed by birch trees. One of the most effective way with dealing with this problem is applying soil sulfur ( 90%). The canopy spread of the tree must be measured to determine the treatment area. The tree is measured from dripline to dripline, north to south. Then measure east to west and multiple the two figures for the canopy spread. If a tree is 10 ft x 10 ft = 100 feet. Spread about 5 lbs. with a lawn spreader over the surface under the tree’s canopy. Then water in immediately with a sprinkler. Call the City Forester for updated information and advice on whether it is an advantage to treat your tree.