Fire Blight

Fire Blight

Common Tree Diseases in California Cities

Do your usual tree management tactics seem to be falling short? The California climate, temperature extremes, and pollution can certainly do a number on landscaping, impacting tree health. However, the Arborwell team knows that disease may also be to blame. How can you distinguish environmental stress from illness? Check the trees on your California property regularly, watching for signs of these common tree diseases.

Anthracnose

Anthracnose is a fungus that affects a variety of plants and trees. It thrives in warm, moist conditions and multiplies very quickly during rainy spells, spreading through infected plant debris. Our plant health care experts identify it by the dark, sunken lesions it produces on affected flowers, fruits, leaves, and stems, which begin as small, irregular yellow-brown spots that darken and spread. Fortunately, with proper tree care from our knowledgeable arborists, anthracnose is not lethal.

Fire Blight

The Arborwell team frequently encounters this bacterial disease in the early spring. Though it doesn’t affect a wide variety of tree types, it is incredibly contagious and can cause significant damage very quickly. Fire blight attacks all parts of the tree, including blossoms, leaves, and branches, giving them a dark brown or black scorched appearance. It spreads through many vectors, including wind, rain, insects, and birds, and is frequently seen on California’s apple and pear trees. Left unchecked, it can kill a tree, necessitating removal and replacement.

Fusarium Wilt

Fusarium wilt is another widespread fungus we frequently see throughout the state. It is known for attacking food crops such as tomatoes and bananas and is one of many diseases affecting California palm trees. Fusarium oxysporum can live indefinitely in the soil without access to a living host and spreads easily, making it difficult to eradicate. The infection begins in the roots, interfering with water transport, causing lower (older) leaves to wilt and yellow. The disease then progresses to new growth until the plant eventually dies.

The Role of Pests and Disease

Experienced arborists know that weak and diseased plants are naturally more susceptible to pests. Infestations can quickly go from being an unsightly nuisance to a major problem, claiming the life of the trees on your commercial property. Watch out for these common offenders on sick or diseased trees:

  • Royal palm bugs
    These tiny, oval, yellowish bugs feed only on the freshly opened leaves of royal palms. Though they can make your palms weak and unattractive, if addressed quickly, we can save your trees.
  • Cabbage palm caterpillar
    Cabbage palm caterpillars feed on palm flowers, weakening the tree. Their reddish-brown larva also stains the tree, leaving behind an ugly mess. 
  • Palmetto weevils
    If young leaves on your palm trees are wilting and quickly dying, you may have palmetto weevils. If you don’t eradicate them fast, these black or red-winged pests can quickly kill your trees.
  • Gold spotted oak borers
    These tiny, invasive beetles kill oak trees and are fundamentally changing the landscape in the region.
  • Oak worms
    Oak worms feed on oak leaves, quickly consuming lush canopies to leave behind a scruffy, leafless tree. Caterpillars fall off trees en masse in May, littering patios, cars, and people.

Identify and manage common tree diseases in California cities with the help of Arborwell Professional Tree Management. Fill out our online form to schedule an arborist assessment for your ailing trees, or contact us at today.

Anthracnose, Fire Blight, fusarium wilt, tree health, tree management

Arbor-wellness: Fire Blight

This time of year, it is often easy to spot an ornamental pear in the landscape because it will often have burned tips with brown leaves at the tip of branches. This is a classic symptom of a bacterial disease called fireblight. This difficult to control disease starts in the spring by small infections at the tip of a branch and moves further down the branch during the spring, killing as it goes. The result is the blackened tips that usually have a bend or crook in them, similar to a “shepherd crook”.  Ornamental Pears are the most common tree in the landscape in our region that get fireblight, but apples, firethorn, crabapples and several other species are also susceptible.  Click here to find out about fireblight control and how Arborwell can help prevent this on your trees.

My trees seem to be dying at the tips, what is this?

If the tips are crooked, the color is dark brown to black and the tree is in the apple family, it is probably a bacterial disease called fireblight.

How do I suppress it?

Fire blight is a bacterial disease so it behaves somewhat differently that most fungal diseases and control of it can be a little more complicated. Fall or winter preventative treatments are the most cost-effective way to suppress fireblight on susceptible trees. If your trees are already infected, we treat with an antibiotic injection as well as the preventative treatment. These two treatments together seem to be very effective.

What kinds of trees get fireblight?

Trees and shrubs in the apple family are susceptible to fireblight. This includes Apples, pears, crabapple, hawthorn, loquat, mountain ash and toyon and shrubs like firethorn and rose. Because it will spread by wind and rain from one type of plant to another, treating all the susceptible plants on your site is usually a wise idea.

How do I get rid of the dead tips, there seems to be a lot of them?

Proper pruning is really critical when you have fireblight. Pruning needs to remove all of the infected stem, so knowing how far down to make the cut is very important. Disinfecting the tools used to prune with is also important because bacterial spores from an infected tree can transport fireblight to other trees very readily. Timing of when to prune is also important. When a tree is pruned during the time fireblight is active, new infections can more easily occur.  At Arborwell, we know how to make a good management plan for your ornamental pears and other susceptible trees that maintains their health and safety for years to come. Contact your Arborwell certified arborist for professional management of fireblight and all your tree needs.

Fire Blight, plant health care, trees

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