The Most Common Landscape Pests and Plant Diseases (And What To Do About Them)

We’ll warn you right now: this is not a pretty subject. We’re talking bugs that can devour an entire evergreen tree. Pale, squishy grubs with soft bodies and legs near their heads. A virus spread by mites that will decimate your precious roses.

Yuck.

But, knowledge is power. So set your squeamishness aside and learn what to do about the most common pests and landscape plant diseases on your property.

First Up: The Most Common Pests In The Landscape

Let’s get the creepy crawlies out of the way first.

Bagworms

Bagworm caterpillars make 1 to 2-inch long bags that hang from the branches of trees and shrubs. Don’t let the small size fool you. Inside: 300 or more eggs. When the eggs hatch in the spring, the tiny larvae crawl out — and they’re really hungry.

These pests can gobble up evergreen trees, stripping them of their needles. They love arborvitaes, juniper and pines.

What to do? Pull the bags off and crush them, if there are just a few of them.

If there are more than you can handle, call the experts.

Japanese Beetles

These pests can make the leaves of roses look like lace — and not in a pretty way. They attack other plants, too, including crape myrtles and birch trees.

Your neighbor might suggest you put out traps specifically designed for Japanese beetles that are baited with a scent that attracts them. The risk? Beetles might show up, but munch your plants instead of landing in the trap.

Try picking them off by hand, then squashing them.

Aphids

If you love azaleas, you hate aphids. The beloved flowering shrubs are among their favorite feasts.

Aphids are small oval bugs and can be brown, yellow, green, red or black and have antennae. (There are thousands of varieties.) A few aphids won’t do much harm. But if your yard is infested with them, aphids’ appetites will cause wilted leaves and will stunt your plants’ growth.

They also ooze a sweet, sticky fluid that attracts ants and causes a black mold to grow on leaves.

What to do? You can try to hose aphids off of your plants or buy a batch of ladybugs to release on your property. They love gobbling up aphids.

Grubs

These squishy critters are as icky as they sound. Turf pests, they eat your lawn’s root system, causing large sections of grass to die and pull away easily from the soil.

Lawn grubs are actually the immature form of beetles, from Japanese beetles to June bugs.

White and C-shaped, their bodies are soft and their legs are up near their heads. They eventually turn into adult beetles, emerging from the ground to mate — and create even more grubs.

What to do? If you have just a few grubs, your lawn can likely withstand them. If you choose chemical grub control, note that it works best in mid to late summer.  

Scale

A lot of people think scale is a plant disease, but it’s actually tiny insects that hang out on plants and feed off sap. There are thousands of different kinds of scale, but they typically look like little bumps. Some scale are soft and others have a hard shell that protects them from predators.

They typically love to attack magnolia, euonymus and fruit trees.

If you catch scale early, try pruning out the infected branches. Look closely to be sure you nabbed them all.

Next Up: Landscape Plant Diseases

Diseases can be as dangerous to your landscape as insects, settling in and spreading quickly.

Some of the worst offenders:

Cankers

Cankers are dead sections of bark on trees and shrubs, often caused by bacteria or fungus. If enough of a tree or shrub’s bark is affected, all of the plant above the canker can die.

As branches weaken and die, they typically fall off, posing a hazard to people and property below.

What to do? The best defense is to keep trees and shrubs healthy, so they can better resist disease. You can carefully remove the infected parts, sterilizing your equipment between cuts.

Juniper Twig Blight

Juniper twig blight is a fungus that attacks the new shoots and tips of junipers, as well as arborvitae, usually in early spring. The branch tips will turn light green or dark gray, and the disease will gradually spread into the center of the plant.

What to do? Prune out the affected branches, then be sure to rake up and dispose of all the debris. Then sterilize your pruners so you don't spread the disease to other plants. 

Rose Rosette

Rose rosette is the latest rose virus confounding experts, as there’s not much that can stop it. It’s slowly taking over even roses that have been bred to be disease resistant, like the Knock Out variety.

Infected bushes first show reddened stems and stunted growth. Flowers start to die, and an infected plant can die within a couple years.

What to do? Dig up infected plants and dispose of them. Then, keep a close eye on neighboring plants for symptoms.

Level Green Experts: Your Best Defense

It’s often hard to tell what’s attacking your plants — pests in the landscape or disease? That’s where we come in.

At Level Green, we’re experts in diagnosing the most common pests and landscape plant diseases.

And we know exactly how to banish them so your plants can return to great health — without harming the other, unaffected plants in your landscape.

While you might spray the heck out of your property to try to nab the offender, we’re more targeted in our approach. We know, for instance, that the insects on your roses won’t migrate to the junipers next to them, so we won’t spray the junipers. It’s a safer way to attack.

We can diagnose the difference between grub damage and lack of water. Or maybe your offender is a mole or vole. We’ll act accordingly.

Trust Your Plants’ Health To Level Green

If you’re not already a Level Green Landscaping client, we’d love to add you to our growing list of happy customers. Our focus is on commercial properties like offices, mixed-use sites, HOAs, municipalities and institutions in Maryland, Washington DC and parts of Virginia.

Contact us at 202-544-0968. You can also request a free consultation online to meet with us one-on-one.

We’d love to hear from you.

Image sources: bagworm, japanese beetle, aphids, grub, scale, cankers, twig blight