The Pacific Northwest can be a paradise for healthy, green turf but sometimes lawn pests and diseases are plotting against you. From crane flies to necrotic ringspots, learn the most common Pacific Northwest lawn problems to watch out for.
Discover what’s going on under the blades of grass in your yard and be vigilant to keep your lawn looking like the emerald carpet you’ve always dreamed of.
Common Pacific Northwest lawn diseases
Brown patch
Brown patch is a common lawn disease in the Pacific Northwest, caused by a fast-acting fungus that turns grass blades brown. This disease thrives in hot, humid summer weather.
It appears as large brown circles on your lawn and sometimes the center of the circle recovers, creating a donut-like pattern. A grayish-white band, often called a “smoke ring” forms around the perimeter. Lawns that are overfertilized or overwatered are more prone to this infection.
Dollar spot
Dollar spot is a lawn disease caused by a fungus. It begins as a small, bleached-brown, or tan spot, the size of a silver coin dollar. The disease appears in the spring and the spots can expand to about 6 inches wide.
A key sign of dollar spot in your lawn is upright grass blades with tan or straw-colored lesions bordered by dark brown edges.
Fairy ring
Fairy ring is a lawn disease caused by fungi, often found in soil rich in organic matter or areas where trees were recently removed. It appears in three different ways:
- Rings of brown, wilted dead grass.
- Dense rings of dark green grass.
- Circle of mushrooms or puffballs.
No matter the manifestation, fairy rings always create a circular pattern in your yard. Check our guide on What is Fairy Ring and How to Get Rid of It.
Fusarium patch
Fusarium patch is another lawn problem that plagues Pacific Northwest yards, particularly those west of the Cascade Range. This disease shows up as reddish-brown circular patches, usually 1 to 2 inches in diameter. Interestingly, the center of these patches might still contain healthy turf, creating a sort of “bullseye” effect on your lawn.
Fusarium patch thrives in cold weather, especially when temperatures dip below 60 degrees Fahrenheit, making it a common sight in early spring. Over-fertilized lawns are more susceptible, especially if you have annual bluegrass, tall fescue, or bentgrass. This disease can even develop under snow or as it begins to melt, catching many homeowners off guard.
Moss
Moss is a common sight in the Pacific Northwest, especially in the western regions where the mild, wet winters create the perfect conditions for it to thrive. While moss can actually be a beautiful and natural addition to your yard, blending seamlessly into the landscape, it’s not always welcome in a traditional lawn. If you enjoy the look of moss, you might consider incorporating it into your yard design. Interested? Here is a guide on How to Grow a Moss Lawn.
However, if a moss-free lawn is your goal, it’s important to understand that moss is more of a symptom than a cause of lawn problems.
Moss tends to grow where grass struggles, that is areas with acidic soil, low nutrient levels, lots of shade, or compacted soil. To effectively reduce moss and encourage healthy grass growth, you need to address these underlying issues. Check this article on How to Get Rid of Moss in Your Lawn
Necrotic ringspot
Necrotic ringspot is another lawn villain you might encounter in the Pacific Northwest, particularly if you’re east of the Cascade Range. This disease is caused by a fungus that attacks the roots of your grass, creating straw-colored rings that range from 2 to 5 inches wide, often with reddish-brown edges.
Kentucky bluegrass or fine fescue with an excessive thatch layer, are especially vulnerable. The fungus typically infects the grass in the fall, but you won’t see the telltale rings until summer. Here’s a guide on What is Necrotic Ring Spot and How to Get Rid of It.
Red thread
Red thread is one of those lawn issues that seems tailor-made for the Pacific Northwest’s climate, especially if you’re west of the Cascade Range. This fungus loves to set up in nutrient-poor soils with low nitrogen levels. If you are dealing with red thread your lawn might start showing signs from mid-spring to mid-summer.
Look for irregularly shaped yellow patches ranging from 2 to 24 inches across. As the disease progresses, these patches can turn brown and dead-looking, with turf that might become a mix of brown, green, and reddish on the tips. Red thread is fond of perennial ryegrass. Luckily it’s mostly a cosmetic issue that will rarely kill your grass.
Check this guide on What is Red Thread and How to Get Rid of It.
Rust
Rust is caused by a group of fungi. It is commonly a cosmetic problem but in severe cases, it can kill the grass blades. The first signs of rust are small yellow spots on grass leaves, which eventually expand into raised orange or yellow pustules. These pustules burst, releasing powdery spores that can be orange, brown, yellow, or red.
You may notice orange dust on your shoes or clothes after walking on an infected lawn. It appears in the fall especially when a lawn is under-fertilized.
Check our complete guide on What is Rust in the Lawn and How to Get Rid of It.
Snow mold
Snow mold is caused by cold-resistant fungis. It develops when the grass is covered by snow for more than 60 to 90 days, especially on lawns with a heavy thatch layer.
Snow mold creates circular patches with dead grass at the center, but it only affects the grass leaves and doesn’t kill the base of the plant. The fluffy mass of fungal growth disappears within a month after the snow melts. This lawn disease can also trigger allergies and health problems for people.
Common Pacific Northwest lawn pests
Chafer beetles
Chafer beetles are another lawn menace in the Pacific Northwest, particularly known for the damage their larvae cause. The adult chafer beetle is brick-colored to light brown and has an oval shape of a half-inch long. They don’t harm the turf, they don’t eat, bite, or sting. The real trouble begins when the beetles lay their eggs in the soil during summer.
The larvae, known as grubs, hatch and start feasting on the grassroots, leading to patches of dead, brown turf. The larvae are C-shaped and white with a dark head, and do most of their damage in the spring when they’re actively feeding on the grass.
As the drier months approach, heavy infestations can lead to significant browning and even death of your lawn, making chafer beetles a pest to watch out for if you want to keep your grass healthy.
Crane flies
Crane flies are a common pest in Pacific Northwest lawns, and while the adults may look like oversized mosquitoes with extra-long legs, they’re harmless to humans. However, their larvae can destroy your turf. These insects attack all types of grass, leaving behind dead, patchy spots that can make your lawn look like it’s been through a battle.
While adult crane flies emerge in the summer, the real damage happens in the spring when the larvae are active. The best time to tackle this problem is during the larvae stage, so keep an eye out when the weather warms up. You can find the larvae by digging around the thatch layer just beneath the grass: look for brown, tough-skinned critters.
Crane flies are often drawn to wet or waterlogged areas, so if your lawn tends to stay damp, you might be at a higher risk for an infestation.
Cutworms
Cutworms are a common pest in Pacific Northwest lawns, though they are not worms, they are the larvae of various moth species. These larvae feed on plant stems, causing wilting grass in spring. They are tricky to identify since they vary in color and size. They grow up to an inch long. They are yellow, green, or brown with some sporting stripes.
Cutworms are most active during spring and early summer. Signs of cutworm activity include increased bird activity and black pellet-like droppings near damaged plants. You will notice fresh damage in the morning, as cutworms feed at night.
Slugs and snails
The climate of the Pacific Northwest is a paradise for slugs and snails. These slimy pests can cause great damage to plants and grasses by chewing through leaves and stems, leaving behind a trail of destruction and slime. They are mostly active at night, but don’t be surprised if you catch them munching your grass during the day when it’s overcast, cool, and damp.
Often, you’ll notice the damage they’ve caused before you see the culprits. Slugs and snails scrape or shred leaves, creating ragged holes that can lead to stunted growth or even plant death if the infestation is severe.
Voles
Voles are small, burrowing rodents that can cause big problems for lawns in the Pacific Northwest. They have compact, robust bodies, short legs, and a chestnut-brown color. They measure about 5 to 7 inches long, including their short, hairy tails. While they may look harmless, voles can eat plants, bulbs, and tubers. In the fall and winter, they also eat the bark and roots of trees.
Though voles don’t pose any health risks to humans, their burrowing habits can create ugly runways across your lawn. These pathways of dead grass can ruin the look of your landscape, making it look more like a maze than a manicured yard. If you start noticing these signs, you might have some voles under your lawn. Here’s our guide on How to Get Rid of Voles in Your Yard.
FAQ about Common Pacific Northwest Lawn Problems
Should I apply pesticide if I have a pest problem on my lawn?
Pesticides aren’t always the first choice for dealing with a pest problem, but in some cases, they may be the most effective solution to eliminate the issue. Here’s a Guide to Using Pesticides on Your Lawn
What if I can’t identify my lawn disease?
Identifying lawn diseases can be tricky, as many share similar symptoms. If you’re struggling to pinpoint the exact problem affecting your lawn, consider reaching out to a local diagnostic or turfgrass pathology lab for professional assistance.
How can I prevent lawn diseases?
Maintaining a healthy lawn starts with proper care and regular upkeep. This includes correct fertilization, mowing, soil amendments, and watering. By taking these proactive steps, you can strengthen your lawn and make it more resilient against diseases. A well-cared-for lawn is your best defense against potential problems.
Contact a professional
Red thread, moss, and chafer beetles are just a few of the challenges that can affect lawns in the Pacific Northwest. No matter where you are in Idaho, Washington, or Oregon, a lawn care professional can offer the expertise and support needed to keep your lawn looking its best. They can help you maintain a healthy, green lawn you can be proud of.
More lawn care and landscaping resources for the Pacific Northwest:
- The Best Lawn Fertilizer for the Pacific Northwest
- When to Apply Lime to Your Lawn in the Pacific Northwest
- The Best Grass Seed for Pacific Northwest Lawns
- The Best Lawn Alternatives for the Pacific Northwest
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