Diseases of pecan (
Inonotus heartrot
White rot of the heartwood of pecan (Carya illinoensis) and other living hardwoods is caused by Inonotus munzii, a polypore fungus found in the southwestern United States and northern Mexico. The basidiocarps (fruiting structures) are often in clusters on the trunk (photo 1). They are bright yellowish brown when they first form, usually during the summer monsoons, then become reddish brown and later blackened. The pore surface (the bottom side of the fruiting body) is yellowish brown (photo 2). The basidiocarps will continue to grow and fruit on dead trees and stumps.
Inonotus munzii is one of the main causes of decay in trees such as native willows (Salix) and cottonwood (Populus). It has been reported on California pepper tree (Schinus molle), white mulberry (Morus alba), maple (Acer), figs (Ficus), oak (Quercus), sycamore (Platanus), elderberry (Sambucus) and elm (Ulmus).
Diseased trees will decline but may not die for years. Branch dieback is common and trees should be watched carefully once limbs die and become a hazard. Dying trees should be removed and the wood either burned immediately or disposed of since the fungus continues to live on the dead wood. Prevent wounds in the trunk and roots to reduce chances of infection. No controls are available once trees are infected.
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April 7, 2007