Bark beetles threaten ice-damaged timber

RAYMOND, Miss. -- Mississippi State University Extension Service forestry specialists are encouraging timberland owners to keep a watchful eye on their property for signs of bark beetles and disease after January’s ice storm.

Of Mississippi’s five species of bark beetles, the three species of Ips engraver beetles and southern pine beetles, or SPB, raise the most concern. Black turpentine beetles are not as common or as deadly and are of least concern.

“Any of our five species of bark beetles will take advantage of stressed pines, particularly broken limbs and trunks from the recent ice damage,” said Butch Bailey, a forestry specialist with MSU Extension.

It is common to see an increase in Ips beetles after an event like an ice storm. But potential attacks by any of these beetles could be compounded because of the cumulative stress trees sustained since the statewide drought of 2023, Bailey said.

“Trees carry stress for a long time -- for years,” he said. “Each stressor reduces trees’ ability to fight off insects and disease. Even though we’ve had decent rain over the past year, the trees are still not fully recovered from what I hope was a once-in-a-lifetime drought in 2023 and extreme heat.”

All beetle species are active anytime the air temperature is warm. That means landowners should begin monitoring their stands now and continue throughout the year. Beetle populations will grow through the summer and peak in October and November before falling through the winter, Bailey said.

“The first sign that most landowners notice is fading or red tops to the pines,” he said. “But this is not the first sign. The first sign will be pitch tubes, which are where the beetles first dig in under the bark. These are small balls of dried sap and inner bark that are pea-sized up to dime- or nickel-sized and stuck on the trunk.”

Broken limbs and trunks of pine trees release chemicals that attract certain Ips species. This in combination with the warm temperatures just after the storm means a heightened degree of susceptibility, said Kristy McAndrew, Extension forestry health specialist.

“What makes me most nervous about this ice storm is how quickly it started warming up after the damage,” she said. “Because we reached flying temperatures within a week of the damage, these beetles were likely flying on the landscape when these chemicals were fresh and easy for them to detect.”

While circumstances seem to indicate beetles will be active, environmental conditions determine how bad any potential attack will become.

“All of these beetles are good at killing stressed trees, but the conditions that lead to outbreak levels are where a big difference comes in,” McAndrew said. “Southern pine beetles are cyclical, and outbreaks don’t rely on stress of trees, whereas Ips tend to rely on landscape-wide disturbances like a huge drought or a lot of storm damage to reach outbreak levels.”

If safe, removing and burning slash, or timber debris, can help deter Ips beetles and reduce fuel that can feed wildfires later in the season. However, many burn bans have been enacted throughout the state, and landowners should check the status of their area before burning.

Landowners who observe issues throughout a stand should call their local MSU Extension agent or a registered forester.

For more information, download MSU Extension Publications 2876, “Ips: The Other Pine Bark Beetles” and 2748, “Southern Pine Beetle in Mississippi: An Overview.”

Learn the signs that indicate bark beetles are active and what to do about it in our related article Defend trees from beetles, disease in storm aftermath.