Pine Bark Beetle Control Methods are Changing

Pine bark beetle calls are being received in increasing numbers, as expected. These beetles attack and kill pine trees that have been stressed. Naturally, the most common stress for pines that invite pine bark beetles is lightning. This is why when we get into our storm season we get many calls asking about how to control these pests.

This year the answer will have a different twist due to the loss of two insecticides that were commonly recommended. Dursban and Lindane have helped to control the spread of bark beetles, but are now difficult to find. So what can we spray our tree with now?

Stan Rosenthal, Forestry Extension Agent in Leon County, has researched the topic and reports the following: Lindane has not been canceled by the Environmental Protection Agency, but is disappearing from shelves nonetheless. Apparently, manufacturers have slowed, or stopped production.

Dursban, on the other hand, is being canceled by the EPA, with most uses and products being officially gone by the end of the year. At present, there are no other registered, labeled, legal and scientifically-proven, effective replacement insecticides for use against pine bark beetles.

Though technically Lindane and Dursban can currently be recommended, it appears that they are out of the picture in most cases. Few, if any of these products now carry labels that allow residential use.

According to Jim Meeker, Forest Entomologist with the Florida Division of Forestry, things are about to change regarding pine bark beetle control in residential settings. He says “it appears that we will have to rely on sound tree care and maintenance, rather than depend upon the crutch of an insecticide.”

Pines in a landscape should be maintained at a low enough density that the tops of the trees are not touching. Thick stands of trees may look nice, but they compete with each other and thus become weaker and more likely to succumb to pine bark beetle infestations. Adequate mulch beds under the trees also help them to stay more vigorous and healthy. Mulch should be two to four inches deep and not piled up against the trunks. Mulch should extend out at least as far as the branches spread. The easiest way to maintain such a mulch is to just let the pine needles stay where they fall.

If all pine needles on an infested tree turn brown at one time, that tree is going to be lost to pine bark beetles. It should be removed as soon as possible. If left standing it is a breeding area for more beetles that could attack adjacent trees.

Question of the Month: When I mow the lawn I see many black insects with orange stripes flying from the grass. What are they, and are they causing any damage to the lawn.

Answer: This could be the adult stage of the two-lined spittlebug, which can seriously damage centipedegrass if it is heavily infested. First, make a positive identification. The insect is about one-fourth of an inch long and black, with two orange stripes running crosswise of its body.

The immature stage, or nymph, also damages the grass by piercing and sucking juices from the stems. Part the grass and look for masses of spittle, each containing a cream colored insect.

Contact your Extension Agent, garden center, nursery or landscape maintenance professional if spittlebug is found in high numbers in your centipede lawn. Control measures are often required.