UAEX Plant Health Clinic

🌱 What happened to this sweet potato vine?!

This unusual growth has a name: fasciation.

Fasciation is an abnormal growth pattern that can cause plant parts—including stems, flowers, leaves, and even fruits—to become flattened, broadened, elongated, fused, or otherwise distorted. In this case, the sweet potato vine has developed a remarkably wide, ribbon-like stem with numerous shoots emerging along its length!

So, what causes fasciation? That’s the tricky part—it isn’t always known. Fasciation can sometimes be associated with genetic mutations, damage to growing tissues, hormonal imbalances, environmental stress, or certain pathogens. In many cases, however, it appears sporadically and there is no obvious cause.

The good news? Fasciation itself is generally not harmful to the plant and doesn’t necessarily mean something is wrong. A plant can continue growing normally even when one part develops fasciation.

Plants certainly have some interesting ways of growing! 🌿

🥒🍈 Is your cucumber or melon plant suddenly wilting? Bacterial wilt could be the culprit.

We recently diagnosed a melon plant with bacterial wilt, a disease spread by cucumber beetles that impacts all cucurbits (cucumbers, melons, squash, pumpkins, and gourds). The bacteria responsible for the disease survive the winter inside the cucumber beetles and are introduced into plants as the beetles feed.

🔍 Symptoms:
• Sudden wilting, even when the soil has plenty of moisture
• Leaves that may recover at night early in the disease
• Yellowing and browning of leaves as the plant eventually dies

Unfortunately, there is no cure once a plant is infected, so prevention is key.

🪲 Protect your cucurbits by:
• Scouting early for cucumber beetles and managing them before they feed on your plants and spread the disease
• Removing infected plants promptly
• Planting a trap crop around the garden
• Using row covers early in the season (remove them when flowers open to allow pollination)

Think your cucurbit plant has bacterial wilt? The Arkansas Plant Health Clinic is here to help with diagnosis!

Photos: Bacterial wilt in pumpkin (Jim Jasinski, Bugwood.org), striped cucumber beetles feeding on a cucurbit stem (Clemson University, Bugwood.org) , and bacteria streaming out of the crown of a pumpkin plant (Taylor Klass, UADA).

Great information on bacterial wetwood!

Why is my tree “bleeding” white foam? We’ve had several calls this week!

The White County Extension Office has received several calls and text messages this week about trees oozing a white, foamy substance from the trunk or large limbs. While it may look alarming, this is often slime flux, also known as bacterial wetwood.

Slime flux occurs when naturally occurring bacteria inside the tree ferment sap. As pressure builds, the liquid is forced out through a crack, pruning wound, or other injury. When the sap reaches the outside of the tree, it may appear dark, wet, bubbly, or even foamy like the photo below.

You may also notice flies, beetles, ants, or other insects gathering around the ooze. Don’t worry—they’re attracted to the sugary, fermenting sap and are not the cause of the problem.

What should you do?
✅ Keep the tree watered during extended hot, dry weather.
✅ Apply 2–3 inches of mulch around the base of the tree (but keep it away from the trunk).
✅ Avoid wounding the trunk with mowers, w**d eaters, or unnecessary pruning.

What should you NOT do?
❌ Don’t drill holes into the tree to “drain” the sap.
❌ Don’t paint or seal the wound.
❌ Don’t spray insecticides or fungicides on the affected area.

In many cases, otherwise healthy trees can live with slime flux for many years. The best treatment is reducing stress and maintaining good overall tree health. However, if you notice extensive dieback, large dead limbs, or have concerns about the tree’s safety, it may be time to have it evaluated by a certified arborist.

If you’re seeing something unusual on your trees and aren’t sure what it is, feel free to contact the White County Extension Office. We’re always happy to help identify problems and recommend the best course of action!

☀️ The heat isn't just hard on you—it's hard on your plants, too!

With temperatures soaring and little rainfall in many areas, even established trees and shrubs can become drought stressed. While mature landscape plants are more resilient than newly planted ones, they still benefit from supplemental watering during extended dry periods.

💧 Water trees and shrubs deeply about once a week when rainfall is lacking. A slow, deep soaking encourages roots to grow deeper into the soil, making plants more resilient to drought than frequent, shallow watering.

🚿 Don't rely on your sprinkler system to do the job. Most lawn irrigation systems don't provide enough water to adequately soak a tree or shrub's root zone. They can also keep leaves and needles wet, creating conditions that favor certain plant diseases. Instead, water at the base of the plant using a soaker hose, drip irrigation, or a slow-running garden hose.

Keep an eye out for signs of drought stress, such as wilting, leaf scorch, premature leaf drop, or thinning canopies. Providing water before severe stress develops can help plants stay healthier and reduce their susceptibility to insects and diseases.

🌳 A deep drink now can help your landscape weather the heat!

Photo credit: The Morton Arboretum

🚨 Your plants may be trying to tell you something.

Summer's heat and humidity are fueling certain diseases and pests across Arkansas. Before you assume what's wrong, check out our latest Arkansas Plant Health Clinic newsletter for the symptoms, causes, and management of issues we're seeing now—including southern blight, fusarium wilt, tomato pith necrosis, and bagworms.

🌿 Read the newsletter here: https://myemail.constantcontact.com/Arkansas-Plant-Health-Clinic-Newsletter-2026.html?soid=1142165174559&aid=rX6CkxjpCVw

Photos: Bagworms hanging from an evergreen branch in the landscape (Brian Kunkel, Bugwood.org) and a tomato stem showing southern blight fungal growth and sclerotia (Rebecca A. Melanson, Bugwood.org).

Think the heat is getting to your plants? Spider mites love it. ☀️

These tiny pests thrive during hot, dry weather and can multiply quickly when plants are stressed from drought. Because they're so small, many people don't notice them until damage starts to show.

One of the first signs of spider mites is stippling—tiny yellow or white specks scattered across leaves where mites have been feeding. As populations grow, leaves may develop a bronzed or scorched appearance, become dry and brittle, and eventually drop. Heavy infestations can also produce fine webbing on leaves and stems.

If you suspect spider mites, try the tap test: hold a sheet of white paper under a branch and tap it sharply. Tiny moving specks on the paper may be spider mites.

Management starts with reducing plant stress. Water plants during dry periods and monitor susceptible plants regularly during hot weather. A strong stream of water can help knock mites off leaves, especially when populations are low. Insecticidal soaps can also be effective, but thorough coverage of the leaf undersides is essential. 

🔍 Check the undersides of leaves—catching spider mites early can make all the difference!

The photos show the microscopic spider mites and spider mite eggs as well as the stippling symptoms caused by spider mite feeding.

🍅 Did you know blossom end rot isn't always visible from the outside?

Most gardeners recognize blossom end rot by the dark, sunken spot on the bottom of a tomato. But sometimes the damage is hidden inside the fruit. Slice open an otherwise normal-looking tomato and you may find brown, leathery tissue instead.

Blossom end rot happens when developing fruit doesn't get enough calcium. The problem usually isn't a lack of calcium in the soil—it's that the plant can't move enough calcium into the fruit. Inconsistent watering, drought stress, waterlogged soils, root damage, and over-fertilizing can all contribute.

💧 The best prevention? Keep soil moisture consistent, mulch to help retain moisture, avoid damaging roots, and don't over-fertilize. A soil test can also determine whether your soil actually needs additional calcium.

📸 The photos show internal blossom end rot—an often-overlooked form of this common tomato disorder.

Have you ever cut open a tomato and found a surprise like this?

Happy Fourth of July from the Arkansas Plant Health Clinic! We hope your holiday weekend is filled with good food, great company, and healthy plants. While you're enjoying the outdoors, keep an eye out for symptoms and signs of plant pests and diseases—summer is one of their favorite seasons too! If something doesn't look right, we're here to help. 🌱

Our red, white, and blue diseases pictured are:

Strawberry leaf scorch (Ohio State University Extension)

Powdery mildew on cucumber (Dr. Lina Quesada, NC State)

Blue stain fungi in the sapwood of a tree (Dr. Anne A Madden)

🌳 Are your trees and shrubs suddenly showing dead or browning branches this summer? You are not alone.

Following Arkansas’s severe winter and spring drought and the mid-March freeze, the Arkansas Plant Health Clinic has received many samples with branch dieback caused by opportunistic canker diseases. Stress can weaken woody ornamentals, allowing fungi to infect branches and cause decline.

A common symptom we are seeing—especially on arborvitae—is a sharp transition where foliage above the canker turns brown and dies, while foliage below remains healthy and green.

🔎 Watch for:
• Sudden death of individual branches
• A distinct line between dead and healthy foliage
• Sunken or cracked bark
• Tiny black fungal fruiting bodies on branches

Unfortunately, there are no curative treatments once cankers become established, but early pruning of affected branches and reducing plant stress can help protect the remaining healthy parts of the plant.

Read more about drought stress and canker diseases, along with other timely plant health updates, in our newest Arkansas Plant Health Clinic newsletter: https://myemail.constantcontact.com/Arkansas-Plant-Health-Clinic-Newsletter-2026.html?soid=1142165174559&aid=gVEEhkWe-zg! 

🌱 Reminder that if you're not getting our newsletter via email, but would like to, sign up with this link:

https://lp.constantcontactpages.com/sl/B27IWcC/phc

Photos: Landscape symptoms of Botryosphaeria canker on arborvitae (Jeremy Williams, Tree Climbers LLC), black fungal fruiting bodies erupting through the arborvitae bark (Jason Pavel, UADA), and a sharp transition between healthy and dead arborvitae tissue as a result of Botryosphaeria canker (Drew Johnson, UADA).

🌸 Seeing brown, dusty spots on the undersides of your snapdragon leaves? It could be snapdragon rust!

We recently diagnosed snapdragon rust in the Arkansas Plant Health Clinic. This fungal disease thrives during cool, humid conditions and can spread quickly when leaves stay wet for long periods.

The first signs of infection often appear as pale-yellow spots on the upper leaf surface. Turn the leaf over, and you’ll find the classic symptom—small brown, powdery pustules that contain spores capable of spreading the disease to other snapdragon plants. As the disease progresses, leaves may yellow, dry up, and drop prematurely.

To help reduce rust problems:
🌿 Clean up plant debris
💧 Avoid overhead watering and water at the base of plants when possible
🌬️ Space plants properly to improve air movement and help leaves dry more quickly

Snapdragon rust won’t usually kill your plants, but it can make them look much less attractive. Checking the undersides of leaves is key—those brown, dusty pustules are a dead giveaway!