COLLEGE STATION — Recent and impending ice storms across Texas could increase the spread of oak wilt disease in Texas trees, plant pathologists at Texas A&M University warn.
“Significant damage in the way of broken limbs and branches have resulted from recent ice storms,” said Dr. David Appel, Texas Agricultural Experiment Station plant pathologist. “This damage may be increased by the pruning activities needed to remove branches.”
Oak wilt, which spreads about 75 feet a year from injured trees, is deadly for red or live oaks. Beetles, which have touched fungal mats from infected trees, are attracted to sap that begins to flow from tree wounds.
The disease is particularly prevalent in those counties on or adjacent to the Edward’s Plateau where serious ice damage has occurred, Appel noted.
“The most dangerous time for oak wilt transmission occurs from February through June because spores are being produces then on fungal mats that form on disease red oaks,” explained Dr. Jerral Johnson, Texas Agricultural Extension Service plant pathologist.
Johnson also pointed out that though February is a few weeks away, the warm, wet weather prior to the icy cold fronts may have encouraged the oak wilt pathogen, Ceratocystis fagacearum, to be very active.
Tree owners can take some precautions to guard against the spread of oak wilt on damaged trees, the plant pathologists said.
“All pruning cuts and wounds from broken limbs must be treated with a protective covering,” Johnson said.
Appel noted that wound paints act as a barrier to prevent sap- feeding beetles from carrying the pathogen from the fungal mats to fresh wounds on otherwise healthy trees. It is critical that trees be protected immediately following the wound or cut, Appel said, especially in areas where oak wilt is known to exist.
“Live oaks, Spanish oaks, Shumard oaks and blackjack oaks are particularly susceptible to oak wilt and should be treated in this manner,” Johnson said. “Tree species other than oaks do not need to have wounds and cuts painted.”
The pathologists recommended that pruning operations be done by professional tree pruners to insure continued tree health and development. County Extension agents and area Texas Forest Service representatives can provide additional details about the best approaches for protecting tree health, Johnson said.
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