Four Common Tree Diseases in San Francisco East Bay Region

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There are a few ways that diseases can spread between trees. One way is through direct contact, which can happen when two diseased trees are touching or close to each other. Another way is through vectors like insects or animals that carry the disease from one tree to another. Finally, diseases can also spread through the air, water, or soil.

This article will cover some of the most common diseases afflicting trees in the San Francisco East Bay region to help you identify the threat and know when to call for a professional tree inspection or assistance for tree treatment.

Sooty Mold

The first type of tree disease to understand is the Sooty Mold disease. This fungal thrives on trees enclosed with honeydew, a gluey fluid produced by some insects. While the disease can be dangerous to your trees, it can also bring aphids infestation.

The disease does not infect plants. The mold, on the other hand, might cause indirect damage to the plant by coating the leaves, making it difficult for sunlight to reach the leaf surface. Insufficient sunlight can result in the plant's inability to carry out photosynthesis, which can significantly impact plant growth. In addition to preventing sunlight from reaching the leaf surface, the coated leaves can age and die too soon, resulting in premature leaf fall.

This disease is most usually found during the warm and wet periods and can rapidly spread to different varieties of trees. Also, the infection typically targets fruit trees.

Although sooty mold could infect your trees, this does not mean that the fruits grown on them are unsafe to consume. Before eating, clean the mold from the fruit with mild detergent and heated water.

The good news is that the disease will not wipe out your trees. However, it will damage their overall appearance. The general sign of this disease is furry mold. In addition, the leaves will turn curly yellowish.

Shot Hole Fungus

Second on our list is the Shot Hole disease. This disease primarily attacks the Prunus species, including stone fruit and almond trees. Shot Hole disease is a particular problem for trees in San Francisco because of its weather, the warm and wet winters. The worst of it is that urban pollutants exasperate the disease. The spores of this fungus can be dispersed by wind currents from infected leaves to those of uninfected trees.

Also known as Coryneum blight, the disease causes gaps and brownish-like color in the tree leaves and makes the stems yellowish.

Luckily, shot hole disease primarily impacts the tree's aesthetic, not the tree's life. However, the disease can weaken the tree enough to become vulnerable to other potentially fatal diseases.

Fire Blight

Fire Blight is a highly contagious bacterial disease, causing problems for your trees at the beginning of the early spring. Tree blights can attack several types of trees native to the East Bay, from fruit trees to pines. This disease causes discolorations and wilting of tree leaves and fruits. Additionally, it results in a burned appearance on the trees' bark, some areas around the leaves, and parts of the stems.

This disease acts very fast. In seven or fourteen days, your tree will appear burned and ruined. Fire blight outbreaks occasionally happen after events like heavy rain or hail storms. These events can damage your tree and create wounds where bacteria can enter, affecting the tree.

Suppose there are several trees with the symptoms. It is typical for others to prevail. However, the disease rarely affects other varieties of trees. Commonly, fire blight affects your apple and pear trees.

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