Most Common Tree Disease San Francisco

The wet and sometimes strange weather of the Bay Area can really have an impact on a number of trees and shrubs in our yards. Fog, humidity, and general wetness can all be a hindrance to the way our trees grow and how they flourish. In addition, this type of weather is encouraging to almost every tree disease San Francisco. The damage from human error and pollution from cars can further make the diseases worse. 

In this article, we will talk about the most common tree diseases and tree pests San Francisco. Keep reading to find out more!

Common Tree Disease San Francisco Problems

When it comes to protecting your trees from different diseases and pests, the first thing to do is to stay vigilant about looking at your trees. You have to look at everything from the root line to the tips of the leaves. If you observe carefully, you will be able to know what ‘normal’ looks like, and then you can determine whether there’s something suspicious. Tree services California recommend doing this type of observation at least two or three times a year so you’re always aware of how your trees are doing. 

Let’s take a look at the most common tree diseases and tree pests San Francisco.

1. Sudden Oak Death

Sudden oak death is probably the most serious tree disease San Francisco. Given the name, you may assume that it only affects oak trees, but that’s not the case. However, oak trees are the most susceptible to this disease. The problem persists in the fact that other trees can also get affected if they’re near an infected oak tree. This disease killed millions of trees in California alone, and you need to look for the symptoms whenever you can. 

The disease starts with a water mold followed by forming a canker eventually. This canker is what kills the tree – it bleeds sap out of the tree, eliminating necessary nutrients and everything the tree needs to thrive. Sudden oak death is also considered to be extremely contagious, and some research suggests that the disease is closely related to the Irish Potato Famine. 

Related Posts: Oak Tree Care Oak Tree Diseases California

2. Shot Hole Fungus

Shot hole fungus targets Prunus species, and these are usually almond and stone fruit trees. It represents a big threat in San Francisco due to the wet, warm winters that are common. This type of weather is ideal for the development of all types of fungus, including this one. Additionally, the disease is exasperated by urban pollutants. 

Thankfully, this disease is merely cosmetic, it’s not deadly. Still, the trees do have some degraded performance from trees without the disease due to the holes in leaves that the disease makes. In addition, since your tree gets weakened, it gets vulnerable to other diseases, so you have to react properly to the symptoms.

3. Chinese Elm Anthracnose 

Chinese elm is a very popular tree in San Francisco. There are many reasons why people opt for them, but it is a very well-performing tree and that’s probably the main reason. However, they are one of the trees that are impacted by a specific disease. Surely, other trees are susceptible to anthracnose too, but Chinese elm anthracnose is quite unique. The disease is caused by a fungus that causes individual branches to die, starting with the tips. Tree service San Francisco companies usually refer to this symptom as the “frizzy hair” look. 

It may seem like your tree has recovered if it has been impacted before. Still, according to experts, severe defoliation year after year may weaken the tree and increase its susceptibility to other diseases, insects, and stressful environmental conditions. We recommend hiring a professional to do the pruning for you to prevent the disease from even happening. 

Related Post: Anthracnose Disease In Ash Trees

4. Sooty Mold


When it comes to tree diseases and tree pests San Francisco, Sooty mold is probably one of the most devastating ones. This disease tends to bring pests with it, especially Aphids. It quickly spreads to all kinds of trees and the disease is most commonly found during the spring and summer months. Additionally, the pests that come with the disease reproduce extremely fast and there will be many of them in just about two weeks. 

However, even with all the negatives that Sooty mold brings, the disease won’t actually kill the tree – it will just make it look very ugly. Furry mold growth on the bark and yellow, curling leaves will make it an eyesore in your yard. It possesses the most danger to young and weak trees and is usually affects fruit trees. Still, the fruit covered with sooty molds are edible, you just have to remove the mold. 

5. Fire Blight

Fire blight is a contagious bacterial disease. It usually attacks the trees in the early spring, making them look like they have been burnt. The disease progress very fast, and it will take only about a week or two for everything to look awful. This gives you very little time to react, so prevention is the key to stopping fire blight. 

Unfortunately, since this is a bacterial disease, it spreads very easily – through insects, bees, birds, wind, and rain. It isn’t rare to see a group of trees with the symptoms shortly after one tree has been diagnosed with the disease. Thankfully, it most commonly affects only pear and apple trees, but other trees are susceptible too. Inspect your trees regularly and pay close attention to the symptoms. If you notice anything strange, don’t hesitate to contact your local arborist to get help. 

Local Tree Experts Overview

Prevention is the key to keeping your trees safe from almost every tree disease San Francisco. Regular observation for symptoms is the best thing you can do for your trees. Most diseases are caused by some sort of fungus, and there’s nothing you can do about it due to the specific climate in the area. Contact your local arborist and consult what you can do to help your trees if you notice any of the symptoms.

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