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Common Tree Pests & How to Treat Them

According to Peter Wohlleben, the German author of The Hidden Life of Trees, trees interact with each other through something he calls “The Woodwide Web”. When trees are suffering or under attack from a pest, they message distress through electrical signals to each other via roots and fungi networks in a way similar to the human nervous system. Through these networks, they’re also able to feed other suffering trees, nurture saplings and even prevent certain trees from growing! Trees are communal creatures just like us — they’re just a little more quiet about it.

It’s too bad that trees can’t talk. They’d be able to tell us when they’re feeling sick and when they need treatment! However, there are many other manifestations of illness and disease on trees — many of which are caused by insects, pests and fungus.

Below are some of the most common pests along with the symptoms you’ll notice on an unwell tree:

AnthracnoseAnthracnose is a general term to describe tree diseases caused by fungal pathogens. Some of the most common symptoms include irregularly shaped brown spots or blotches on leaves, distorted or curled leaves or twig blisters. In some cases, trees will even drop their leaves prematurely in the springtime!

AphidsAphids are small (an eighth of an inch long), soft-bodied insects that vary in color, though they’re usually green, yellow, brown red or black. Low or moderate numbers of aphids are usually not an issue, but they can quickly grow in number to turn into a full-blown infestation! Common symptoms include general decline in tree vigor, stunted growth, and yellow leaves that are wilted or curled.

Lace bugsAre you noticing reddish-orange spots on the undersides of some of your trees’ leaves? They may be suffering from an infestation of lace bugs. There are a lot of different types of these out there, but they most often camp out on leaf surfaces, sucking out nutritious fluid. Similarly to aphids, these critters never exceed an eighth of an inch in length. However, they differ in appearance with lacy-looking wings.

Tree scaleNotoriously hard to control, tree scale is one of the most common tree ailments. You might think these look like fungus, but they’re actually small insects that suck sap from the trunks and branches of your trees with needle-like mouths! There are over 1,000 types of tree scale insects. Symptoms include small bumps (the scale insects themselves), yellow or brown leaves, premature leaf drop, dead twigs or branches, and slowed growth.

Wood-boring insectsThere are lots of insects out there that feed on tree wood by boring or burrowing directly into the trunk. These insects vary in shape and size, so rather than identifying the insect, it’s simplest to look for the symptoms, which include sawdust-like deposits, small holes in the bark, wilting leaves, dying branches and a weak canopy. In Massachusetts, the Emerald Ash Borer is fairly well-known because of its invasive nature. Originally from Asia, these insects are absolutely fatal and devastating to ash trees.

The trees of your property’s landscape are under constant attack by insects, pests and fungus. Healthy trees can withstand most of these pests for a time, treating them as minor inconveniences. However, these inconveniences can quickly turn into infestations without proper control and care. Site conditions can become overwhelming to trees if they aren’t maintained well.

The best way to prevent pests from thriving is to improve conditions that support tree health. Take some time to observe your property’s trees for signs of stress. If you’re unsure whether what you’re looking at is a symptom or not, you can always call the experts at Landscape America, and we’ll be happy to assist you. Regular tree inspection and tree inventory services are excellent ways to circumvent pests before they become a problem!



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