Invasive Pests and Diseases Threaten California’s Urban Forests

Invasive pests spreading disease and deadly water molds have spread throughout the state

California’s trees spent the years before 2017 enduring serious drought conditions. Sadly, millions of trees didn’t survive, even after the early 2017 rainstorms made headlines. These storms were followed by a record setting summer. The extreme heat dried out the state’s superbloom and created the conditions for some of the largest wildfires in Californian history.

Weather remains an ever-present concern for trees and the people who care for them. Even now, drought conditions are reappearing throughout the state. However, some threats are less obvious to the casual observer, until it is too late.

Invasive pests and diseases can ruin massive swaths of a tree population. Trees can be resilient to high temperatures a lack of rainfall. Some trees have natural defenses against some pests and diseases. However, this capacity took a very long time to develop. Thanks to changing climate conditions and human intervention, pests and diseases that native trees are not ready for have been introduced. The result is a disrupted ecosystem that endangers thousands, even millions of trees around the U.S.

Citrus greening disease from invasive pests threaten citrus farms and backyard trees alike

The citrus industry across the United States has been in a state of emergency thanks to an invasive pest. The Asian citrus psyllid brought citrus greening disease to the US in 2005. Since then, the disease has spread across the country. There is no known cure for the infection; affected trees will eventually die. The disease gets its name from the obvious ‘greening’ of the fruit on affected trees.

The psyllids themselves are robust, able to fly continuously for up to 50 minutes, for up to a mile in less than an hour.

invasive pests asian citrus psyllid

This Asian Citrus Psyllid carries the bacteria responsible for citrus greening disease. The U.S. citrus industry now faces dramatic economic losses if the disease cannot be contained.

The disease has made its way to California, and already authorities are attempting to control the pest responsible for its spread. As of January 1st, the California Department of Food and Agriculture set down a quarantine in regions across the state. The primary danger is of course to the state’s citrus growing industry. The transport of citrus trees and produce is now strictly controlled and subject to regular inspection.

This danger threatens the citrus tree in your backyard, as well as any other citrus tree in your neighborhood. If you’re the owner of a citrus tree, and live in the Sacramento or Roseville areas, you could potentially have the pest. While the disease itself has yet to be detected in Sacramento, there is no way to guarantee that things will stay this way.

If I have a tree affected by this disease, what do I do?

If you’re seeing the symptoms of citrus greening disease on your tree, contact an arborist immediately. There is sadly very little you can to to preserve the tree if it does have this infection. However, you can give other citrus trees in a neighborhood a better chance to survive.

Fallen Leaf Tree Management can diagnose your trees for this disease. We offer pest management as part of our tree care services. Removal of a tree affected by citrus greening disease can prevent the disease from spreading to other trees. Once the pests in your tree have been properly controlled, we are able to perform swift removal of the tree and its stump.

Not all disease relies on insects to spread!

invasive pests and disease Sudden Oak Death

This hill in Big Sur, California was photographed in 2006. Notice the swaths of dead and dying trees mixed among seemingly healthy neighbors. This hill has been struck by Sudden Oak Death.

Sudden Oak Death is caused by Phytophthora ramorum, a type of water mold that affects specific tree species. Coast live oak, Shreve’s oak, tanoak, canyon live oak, and California black oak are among the species that are affected by the mold.

Surfacing in California in 1995, the disease became rapidly uncontrollable. Over one million trees died to the infection by 2016, and there remains no guaranteed way to control the mold.

Mortality in affected trees can be swift; mature trees succumb within a year of infection. Symptoms differ between affected species. In Tanoaks, the trees most vulnerable to the mold, usually start by having older leaves display in a lighter green color. Within weeks, the leaves will begin to die back. Dark brown sap stains the lower trunk. The bark may split and produce a discolored gum.

The mold can be carried by insects, other animals, and a broad range of plant life. However, the wind and the rain can just as easily carry mold spores to other susceptible trees. Phytophthora ramorum is confirmed in nearly all of coastal California, with counties further inland under advisory. The mold is also suspected of being transported by people walking through areas affected by the mold. The ease of how the mold spreads has allowed it to spread across the entire United States.

The water mold infection is not universally lethal, even within a vulnerable tree species. For example, while the tanoak has been one of the most affected species, some individual tanoaks in a population survive infection.

A tree service company can help you deal with invasive pests, and any pathogens they bring

Trees on your property provide many benefits. However, should they succumb to any pests or disease, they can become a serious danger. If you suspect your trees are suffering from an insect infestation or a disease, it is best to call an arborist for an assessment straight away. The money you spend on this could potentially save you a lot more money in the future.

Sadly, for some problems there’s no cure save removing the tree. Citrus greening disease cannot be stopped once it takes hold in a tree. However, you still have a chance to save other citrus trees if you take swift and decisive action.

As for the deadly water mold responsible for Sudden Oak Death, we are still learning more about how the infection works. We know that some trees are more capable of fighting off the mold than others, and removal is not always the best solution outright. However, if you have a tree that has succumbed to the disease, then it’s best to remove it from the property. In addition to eliminating a source for the mold to spread from, you also are protecting the rest of your property.

Don’t hesitate to contact the Fallen Leaf Tree Management team if you suspect your trees are afflicted by pests or disease. The earlier you identify these problems, the sooner you can develop a solution before disaster strikes.

Fallen Leaf Tree Management

Expert Tree Care in the heart of Sacramento & surrounding areas with your satisfaction guaranteed. One of our Arborists can give you a comprehensive evaluation on all the trees and shrubs in your landscape and give you a scheduled maintenance plan. Call for an arborist consultation.



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