TREE BASICS

Check Your Trees to Prevent Disease

TREE PESTS AND DISEASE have been steadily spreading across the country. The emerald ash borer has killed more than 100 million trees alone. And researchers estimate that 1.4 million street trees will be killed by invasive insects over the next 30 years, costing $900 million to replace.

The good news? The end of the summer is a great time to be proactive and check trees for unwanted visitors. That’s why the U.S. Department of Agriculture has declared that August is Tree Check Month.

HERE ARE 5 COMMON PESTS TO LOOK FOR THIS SUMMER:

Asian Longhorned Beetles

This invasive wood borer attacks maples, elms, buckeyes, birches, willows, and other hardwoods. Once the beetle attacks the tree, it cannot be saved. But diligence is important to keep it from spreading. This pest has already been discovered in the Northeast and the Midwest, and efforts are underway to keep it from spreading further.

Watch for yellowing or drooping leaves, oozing sap, dime-sized exit holes in the trunk and limbs, shallow scars in the bark, dead limbs, and sawdust material where branches meet other branches or at the base of the tree.

Emerald Ash Borers

The emerald ash borer kills millions of ash trees each year and is currently found in 35 states. Adult borers are very small and difficult to spot, but infested trees will exhibit serpentine patterns of feeding tracks packed with frass and sawdust. Later in the season, you may see D-shaped holes in the bark as the adults emerge. You can also watch for crown dieback from the top down and yellowing foliage.

Japanese Beetles

Japanese beetles skeletonize the foliage on trees and shrubs. They also feed on flowers and fruit. Although they will seldom kill trees or shrubs, they can slowly weaken them, making them subject to secondary pests and disease. Their larva will also leave irregular brown spots in lawns.

These beetles tend to appear earlier in the summer and are easy to spot — as is their devastation.

Aphids

Aphids eat away at the sap in tree leaves and stems, leaving behind a sticky syrup called honeydew. Large infestations of aphids can stunt new leaf growth and cause misshapen, curling, or yellow leaves. You can spot an aphid infestation by checking the underside of leaves or watching for sooty mold.

Mountain Pine Beetles

The mountain pine beetle is a small insect native to the western United States. It lives most of its life in the inner bark of ponderosa and limber pine trees. Signs of infestation include popcorn-shaped masses of resin, called “pitch tubes,” where the beetles have entered. The needles on affected trees also generally turn red.

What do I do if my tree is infested?

• Make note of what you found and where you saw it. Take a photo, if possible.

• Capture the insect, place it in a container, and freeze it. Doing so will preserve it for identification by a certified arborist.

• Contact a certified arborist for treatment suggestions and report your findings to your state’s Department of Agriculture.