Oak wilt season upon us
Saturday, April 05, 2008
Avoid pruning oaks now and always paint wounds to help stop destructive tree disease.
Sap-feeding beetles are up to no good, and the Texas Forest Service wants you to know about it.
Now is when nitidulid beetles can spread oak wilt, one of the most destructive tree diseases in the United States. Officials are trying to educate property owners about the disease’s life cycle to prevent new infections, says Eric Beckers, staff forester.
Though all oaks can get oak wilt, red oaks (particularly Spanish oak, Texas red oak, Shumard oak and blackjack oak) are more susceptible. Bottom line: Avoid pruning or injuring oaks from February to June, and paint wounds on oak trees year-round.
Beckers has posted helpful tips at http://www.texasoakwilt.org, which also has information about how oak wilt spreads and tips for preventing it.
Here is an excerpt:
“Starting around mid-March, arborists and foresters begin identifying red oaks that have succumbed to the oak wilt fungus. Some of these diseased trees will form fungal mats, a mushroom-like structure just under the bark.
“These fungal mats are sweet-smelling and attract sap-feeding beetles, which … feed on the spores produced on these mats. These sap-feeding beetles will fly away covered with spores seeking their next meal of tree sap.
“If they happen to feed from a wound on an oak, the spores can dislodge, germinate and infect the new oak — and the neighborhood. This is the beginning of a new oak wilt disease center.
“In Texas, fungal mats can form on diseased red oaks from around the beginning of February through May. Sap beetle activity, and thus dispersal of fungal spores, is also at its peak during this time of year.
“(That) makes this time of year the wrong time for oak pruning. The long-standing recommendations to avoid pruning or injuring oaks now and paint oak wounds year-round tie in directly to the life cycle of the oak wilt pathogen.
“Equally important to stopping the spread of the disease is the eradication of oak-wilt-stricken red oaks, especially those that have died during the fall months.
“These trees generally do not dry out over winter and often harbor the fungus until springtime, when fungal mats begin forming. It is important for communities dealing with oak wilt to monitor the health of red oaks in the immediate area adjoining oak wilt disease centers.”
According to the Web site, a knowledgeable arborist or forester should diagnose red oak trees suspected to have died from oak wilt, which should be destroyed by burning, burying or chipping. Fire destroys the fungus, and the smoke emitted poses no threat to healthy trees. Be sure to check local laws and burn bans.