Oak Wilt
Oak wilt is one of the most destructive tree
diseases in the United States. Oak Wilt is a
fungus, that attacks the vascular system of
susceptible trees thereby disabling the water
conducting tissue. All Oaks are susceptible to
one degree or another, but some are affected
more than others. Red Oaks, particularly Spanish
Oak (Q.texana), Shumard oak (Q. shumardii), and
Blackjack oak (Q. marilandica), are extremely
susceptible and play a unique role in new Oak wilt
infections. White Oaks, including Post Oaks
(Q.stellata), Bur Oak (Q. macrocarpa), and
Chinkapin Oak (Q. muehlenbergii), are resistant to
the fungus and rarely die from Oak Wilt. Live
Oaks (Q. virginiana and Q. fusiformis) are
intermediate to susceptibility to Oak Wilt, but are
most seriously affected due to there tendency to
grow from root sprouts and form vast
interconnected root systems that allow movement
of the fungus between adjacent trees. The
successful management of Oak Wilt depends on
correct diagnosis and an understanding of how the
pathogen spreads between different Oak species.
Foliar symptoms of Oak Wilt on
Live Oak. Veinal necrosis, where
main veins and lateral veins on
leaves become chlorotic and
necrotic, is the most reliable,
diagnostic symptom for Oak wilt in
Live Oak. (click picture for more
detail)