7 Common Arizona Tree Problems and Diseases

December 21, 2022
7 Common Arizona Tree Problems and Diseases

Trees are essential aspects of Arizona’s unique beauty. It’s reasonable to expect native plants, including trees, in Arizona are adapted to the climate, whether they grow in the city, the desert, or the mountains.

All trees can suffer from infections or storm damage. Be alert for these seven common Arizona tree problems and diseases so you can seek professional tree care for your property.

Types of Tree Problems in Arizona

According to the Arizona Department of Forestry and Fire Management, trees in Arizona can suffer from both insect infestations and diseases. In those two broad categories, there are sub-categories with specific features.

Tree Pest and Insect Problems

Insects that attack trees in Arizona cause damage in various ways. They typically attach to different parts of the tree, from bark to sap to foliage. Trees suffering insect infestations may display discolored leaves or needles, fail to replace fallen foliage, or show tunnel tracks when bark falls off.

Insects also bore into trees and foliage to intercept water and nutrients, stealing them from the tree and causing damage and decline.

The bugs that cause several common Arizona tree problems and diseases include the following:

  • Bud and shoot insects munch on the tender shoots and buds of trees, thwarting their growth.
  • Defoliators attack leaves on deciduous trees and needles on conifers, causing early browning or prematurely falling foliage.
  • Sapsuckers burrow into stems and leaves to steal water and nutrients, causing discoloration and possibly spreading other plant diseases.
  • Bark beetles create tunnels between a tree’s trunk and bark, weakening the tree and causing discolored foliage. Bark beetles prefer distressed trees, but they’ll attack healthy trees when large populations of these beetles are present.

Tree Diseases in Arizona

Fungal infections most often cause tree disease. They can appear at the base or root area, causing decay. Fungi may appear on the trunk and branches. Common fungal diseases in Arizona trees include the following:

  • Leaf rust browns foliage and interferes with photosynthesis, the process trees through which trees use sunlight to convert carbon dioxide and water into nutrients.
  • Witch’s broom appears as a tangle of twigs and branches. It develops when a tree tries to re-grow damaged areas. The cluster of leaves, twigs, and branches that forms in reaction to repeated insect or fungal assaults can look like broom head.
  • Mildew shows up as a powdery white coating on leaves, often after a bout of wet weather.
  • Fungi or insects cause galls and cankers. Galls look like bumps on the trunk or branches of a tree and arise due to insects or other pests building nests out of dead leaves or twigs in order to lay eggs. Cankers are other fungal infections that appear as patches of dead bark where the fungus has invaded an injured section of the tree.

Arizona sycamore, aspen, oak, cottonwood, and willow trees can all suffer diseases that cause foliate discoloration or defoliation. These diseases, including black spot, rust, and anthracnose, can stunt or kill the tree. They take advantage of favorable moisture and temperature conditions (wet or cold) to attack weakened trees and destroy foliage.

Fungal infections can cause stems and tree trunks to decay, weakening the tree and making it more susceptible to storm damage.

Environmental Problems

While snowbirds may not think of Arizona as a place with weather extremes, the Grand Canyon state can suffer from too little and too much water. Both drought and monsoons affect trees in Arizona.

Drought deprives trees of vital moisture and weakens them. When Arizona’s monsoons arrive, the excess water can attack roots, resulting in root rot and trees toppling over. Wind can bring down branches weakened by rot, fungus, or insects. Some tree diseases are spread by wind rather than by direct contact with insects or fungi growing at the base, trunk, and branches.

While visitors relish Arizona’s sunshine, trees that endure direct sun all day may suffer greater water deprivation and are more vulnerable to disease, infestation, and decline.

Similarly, temperatures across the state vary wildly, from blasting furnace heat to below-freezing chills that result in frost, snow, or ice.

Any of these variations in local climate can negatively affect Arizona’s trees. Additionally, chemicals used to treat roads or sidewalks can leach into the soil, affecting a tree’s health.


The best way to keep Arizona trees healthy is with preventative maintenance. Here are steps to preserve your trees.

Clearing Debris and Invasive Plants

While beneficial organisms thrive in fallen leaves and twigs by helping them decompose and feed the soil, debris harboring insects under young trees can thwart growth. Keep the ground under saplings clear of dead materials and help them retain moisture with mulch.

Invasive weeds and moisture-hogging grasses can weaken trees and divert water and nutrients. Keep the areas beneath trees clear of intrusive foliage.

Professional Pruning

Homeowners may get away with light tree pruning, but anything above shoulder height or involving branches thicker than four inches requires professional attention. Poor or mistimed pruning can do more harm than good.

Tree care experts know how to prune trees and encourage healthy growth. They can help trees maintain structures that resist wind damage and minimize the spread of disease. Tree services will also remove and destroy diseased branches to keep the infection or infestation from spreading to the rest of the affected tree or nearby trees.

Tree Removal

Sometimes, there is no hope of saving a damaged or diseased tree, no matter how heartbreaking or disappointing it is. Root rot, storm damage, or insect infestations can cause falling limbs or tipping trees that endanger people and property.

Homeowners and commercial property managers should regularly inspect their trees for signs of distress. Look for thinning foliage, dead branches, or signs of mildew, rust, or black spot.

Contact us at Arborcraft if you notice trees on your Phoenix property that don’t look healthy. We are a tree service company in Mesa, AZ, with certified arborists on staff. Our trained professionals supervise every job we do and can explain whether your distressed tree is salvageable or if you’ll need professional tree service.

It’s never easy to make the decision to take a tree down. Still, it’s best to remediate dangerous conditions as soon as possible before a falling tree causes property damage, severe injury, or even death.

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