ProHort Update for July 2026

1. Protect Yourself with the Right Repellent

As people continue to spend time outdoors enjoying the Nebraska weather, they may also be spending time with pests that can make outdoor activities uncomfortable. Using repellents is an important tool for protecting yourself from tick, mosquito and chigger bites. Preventing bites is more than a matter of comfort. Pests such as ticks and mosquitoes can also potentially transmit illness-causing pathogens. Mosquitoes can spread diseases such as West Nile virus, which was recently detected in Lancaster County, and ticks can transmit or cause several other illnesses. 

Unlike insecticides, which kill insects, ticks, and mites, repellents are worn on the skin and work by making it difficult for pests to locate and bite you, interfering with the sensory cues they use to find hosts. When used correctly, repellents create a protective barrier that helps reduce the likelihood of bites. 

When selecting a repellent, choose only products approved by the U.S. Environmental Protection Agency (EPA). EPA registration means the product has been tested for both effectiveness and safety when used according to the label directions. 

EPA-Approved Repellent Active Ingredients 

*Products come in different formulations and vary by hours of protection and minimum age required for use. Use the EPA repellent search tool to choose the repellent that works best for you.

While not applied directly to skin, permethrin-treated clothing is also a good option for preventing bites. Permethrin acts as an insecticide that kills pests that contact it but is safe to wear and can last for many washes. 

Protection time varies by product and concentration, so always read and follow the label instructions when choosing a product that works best for you. 

While many alternative methods are marketed as pest repellents, most have limited evidence supporting their effectiveness. Citronella candles, ultrasonic devices, wearable patches and bracelets, and many other products generally do not provide the same level of protection as EPA-registered repellents. For the best protection, combine repellent use with other preventive measures such as wearing long sleeves and pants, avoiding peak mosquito activity (dawn and dusk) when possible, and performing tick checks after spending time outdoors. 

Disclaimer: Nebraska Extension does not endorse, recommend, or guarantee any specific product, brand, or manufacturer.

More Information - Mosquitoes: A Bad Summer Buzz

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2. June 30th growing degree days (GDD)

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3. Pest Update 

For a more complete list, visit Michigan State University GGD of Landscape Insects or GGD of Conifer Insects.

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4. Rows of Holes in Tree Bark, The Ohio State University

Clientele contact us for all their tree problems. Sometimes that problem is a row of holes in the bark of trees. Read about the culprit of these rows of holes found in many trees and the impact on trees. 

Read more here. 

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5. On the Importance of Covering the Ground (with plants)

By this point we are probably all familiar with the various benefits of mulch: it keeps weeds down, maintains soil moisture, people tend to appreciate the appearance. As the mulch breaks down over time, it can even provide some of that oft-mentioned soil organic matter and broadly benefit the soils of our landscape beds. It guards against temperature swings that can cause plants to heave out of the ground during the freeze-thaw cycles of winter.

That being said, mulch can be an expensive annual cost, it’s a relatively intensive job to apply, weeds still show up and despite the addition of organic matter, it doesn’t really contribute much else to the soil ecosystem. Plus, during the process of application, there’s a lot of traffic that will do more harm than eventual good to the soil structure and many times it only takes one decent rain even to wash it (and soil) away.

Better would be to consider having a little bit less distance in between plants for better ground coverage, erosion control and general soil health. This can still be done in an attractive and structured way by using swaths of low-growing plants to maintain a consistent aesthetic without being too busy. For July we will consider the use of grasses and the grass-like sedges.

As a mulch replacement, or “green mulch” if that’s what you’re into, grasses and sedges are great because for the most part, a single plant can do a lot of work with its drooping blades and interesting flowers and seed heads. There are some that will spread by stolon and form colonies, and some will stay as tidy bunches, growing wider each year. There’s a decent handful of options to choose from that will stay below 1-1.5 feet and not look messy or take away from feature plants.

I’m a fan of sedges because there are low-growing options and species that can tolerate sun to shade, moist to dry.

• Pennsylvania sedge (Carex pensylvanica) tends to stay under a foot, spreads by rhizome, can handle the full range of sun-to-shade and appreciates a minimal watering regimen. Commonly used as a lawn alternative.
• Wood sedge (C. blanda) is a 1-foot-tall workhorse. Plant closer due to its mounding habit, but it can handle all light conditions and virtually any moisture levels but preferring the medium-to-wet side of things. From personal experience, though, I would say it handles neglect fairly well.
• Ivory sedge (C. eburnea) will take the full range of light conditions and loves a dry soil but will do well in higher moisture conditions as well.
• Rosy sedge (C. rosea) is a great choice for shadier areas no matter the moisture availability.
• In terms of growing height, grass options for a ‘groundcover’ are somewhat limited:
• Purple lovegrass (Eragrostis spectabilis) is a good low mounding option with attractive, airy seed heads. Great for dry, full sun areas with fall color that will add to any landscape.
• Blue grama (Bouteloua gracilis) is a very common lawn alternative that would work amongst landscape plants as well, with the ability to be mown or trimmed, interesting seed heads, and far less aggressive behavior than side oats grama.
• Little bluestem (Schizachyrium scoparium) is somewhat more upright, but still forms a decent mound once established. Tried-and-true full sun drought tolerance, general performance and interesting color, this is a great option to fill in open spaces.

You aren’t guaranteed to find all of these at your nearest nursery, but ask about their sedge and low native grass offerings, and maybe the more you name-drop certain varieties the likelier they’ll be to bring them in for the future. And, as with many things conservation, continuing to have conversations with clients about taste and aesthetics is an important first step to expanding resilient, sustainable and relatively low-maintenance landscapes in our communities.

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6. Now is the Time to...

Now is the time to:

• When diagnosing tree, turf and shrub issues, check soil moisture with a long screwdriver or other probe.  Ask your client to tell you about their watering – how much, how often, etc.  Each part of the landscape can be different in terms of soil moisture retention.
• Though it’s not fun, remove weeds from landscape beds at least once a week to keep undesirable plants from competing with the desirable perennials and annuals. 
• Fertilize patio planters and display containers with a half rate of readily soluble nutrients to maintain vigor and prevent stretching.
• Re-apply mulch around trees and shrubs if it has blown or washed away in wind and rainstorms.  Pine needles, wood chips and bark chunks are great choices.
• Keep the mowing height the same all year long. It’s an old recommendation to raise the height in summer; there are some benefits to raising the height now, but overall, more negatives than positives.
• Prune out crossing and broken branches of shade, evergreen and ornamental fruit trees.  Remove no more than 10-20% of the overall canopy as the pruning dose.
• Apply a preventative application of grub control to turf that has had a history of unacceptable damage.  Pay close attention to rate, PPE guidelines and other pertinent label information. 

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7. Chlorosis

Chlorosis is the fading of green leaves to yellow. We can see it happen on any plant. The cause can be waterlogged soils, drought, root damage, high pH and nutrient deficiency (N, Fe, Mn, Mg, Zn, and more). In eastern Nebraska we can see chlorosis in red maples, including hybrids and cultivars, some oaks and birch trees. Most often nutrients are not missing in the soils but they might be in a formulation that the plant is unable to pick up. High pH can also prevent nutrient uptake. Before adding anything to the soil, a soil test should be done to determine soil pH and nutrient content.

More information here.

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8. Phytotoxicity

Dormant oils are often used before bud break on many of our woody ornamental plants to help manage and reduce pest issues. However, summer oils are often used after bud break on plants to help reduce pest pressure. Dormant/summer oils are petroleum based products. They are often considered a low toxic option for pest control. However, some plants such as amur maple are sensitive to oils and will have a phytotoxic response and the leave will burn. Colorado blue spruce trees can be turned green by applying horticulture oils.

Read more about Do's and Don't of Dormant Oils here.

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9. Mid-summer Vegetable Garden Problems
 

Unfortunately vegetable gardens can be affected by many disease problems. Below are symptoms and links to additional information for the most common problems.

• Bacterial wilt of cucurbits - Plants wilt and over night my recover. But eventually plants wilt completely and die. 
• Squash bug - Sudden yellowing and death of plants. 
• Squash vine borer - Sudden wilting/death of vines and/or plants.
• Tomato blossom end rot - Leathery to soft brown/black rot on the blossom end of tomatoes.
• Tomato spotted wilt virus - Upper young leaves bronze and develop small dark spots or flecks; fruit lesions develop unique concentric rings. Transmission by thrips.
• Tomato mosaic virus - Green mottling of leaves; yellowing and stunting of plants; fruit lesions with yellow halos.
• Tomato early blight - Starts with small brown spots on lower leaves. Lesions develop a "bulls-eye" pattern of concentric rings. Infected leave yellow and die. Infection progress up the plant.
• Tomato bacterial spot/speck - Begins as very small black spots on leaves and fruits. Severe infection causes leaf loss and unmarketable fruits.
• Tomato wilts - Several wilt disease affect tomatoes including Fusarium, Verticillium and walnut wilt. Symptoms of each can be very similar, starting with leaves turn yellow, often on one side of stem or branch. Symptoms get progressively worse and whole plant wilts. Eventually plant dies.

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10. Commercial/Non-commercial pesticide applicators

If you have a pesticide applicators license which expired in April 2026 or you need to get a new license, testing options are listed below.

Testing-only Options

• Closed-book exams are given by the Nebraska Department of Agriculture (NDA). Preregistration is not required an there is no cost. Visit the link below for a list of available test-only dates, times and locations - https://pested.unl.edu/.
• NDA computer-based testing is provided through the Pearson-Vue company. Click here for a list of testing sites, categories available, dates, and registration information. Cost $55 per exam. (For applicators with multiple categories on their license, each category is charged the full testing fee.)

Commercial/noncommercial applicators are professionals who apply restricted-use pesticides for hire or compensation. Anyone who applies pesticides to the property of another person, either restricted- or general-use products, for control of pests in lawns, landscapes, buildings or homes must also have a commercial pesticide applicators license. Public employees (those employed by a town, county, state) applying mosquito control pesticides whether restricted- or general-use, must also hold a commercial or noncommercial certification.

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11. Digital Diagnostic Network - Need help with diagnostics?

Do you or your clients have questions you need help answering? Maybe you are a lawn care person and they're asking about trees, shrubs, or flowers? While you can refer them to their local Extension office, another option is Digital Diagnostic Network. Homeowners, lawn care professionals, pest control operators and others are invited to submit questions and photos through this website or with the assistance from an Extension professional at any Nebraska Extension office. All offices are equipped with high-resolution digital image capturing technology. Whether the question is about a lawn weed, insects on a plant, diseases in a shrub border or other, an expert panel of Extension professionals will review and respond to the question. To get started, create an account so the question can be reviewed and responded to via email. For more information and to create an account, go to Digital Diagnostic Network.

Bugging Out With Your Camera Phone - Tips on how to get a good picture.

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Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by Nebraska Extension is implied. Use of commercial and trade names does not imply approval or constitute endorsement by Nebraskas Extension. Nor does it imply discrimination against other similar products.