Tree diseases can cause major risks to tree health. Often in the initial stage, a deadly disease might seem to be a trivial issue. However, it spreads very fast and quickly reaches an uncontrollable stage. In certain severe cases, trees can even die. Hence, controlling tree diseases by proper tree preservation services in San Diego is a must-do for optimum tree health management.

In this blog, we will talk about the diseases your trees can suffer from. Additionally, it provides you with a clear picture of the benefits of hiring professionals for oak tree preservation services. Read more to find out everything about preserving Oak trees from deadly diseases.

Key Diseases Having Devastating Effects On Your Oak Trees

Oak trees play a vital role in preserving the natural ecology of Southern California. But these trees are under threat due to infection of different fungus, insects, and pests. As a result, many native trees are killed, and the natural ecosystem has been dramatically changed. Hence, you need to preserve these trees from deadly diseases by early diagnosis, regular monitoring, and effective treatment.

Oak Wilt

This fungal disease is caused by Bretziella fagacearum that destroys Oak landscapes. The fungus attacks the pointy-tipped leaves of red Oak trees. However, their symptoms are leaf loss and rapid wilting at treetops. In severe conditions, the whole tree dies in a few weeks. After a primary infection takes place, this disease rapidly spreads through roots till the death of the trees. In this condition, tree preservation orders have to be taken by eliminating both underground and overland pathways.

Armillaria Root Rot

Different members of the Armillaria genus cause this fungal root rot that results in yellow to brown foliage, poor growth, and in the end, tree death. The major symptoms are dead branches in upper canopies, honey-colored mushrooms at the tree bases. The infected trees with stringy, soft, white wood fall over or break in storms.

Oak Leaf Blister

At the time of cool wet spring season, this fungal disease is caused by Taphrina caerulescens to red Oak trees. Due to this disease, raised, blister-like, and circular areas are found on the upper surfaces of leaves. The bottom concave and upper convex areas become yellowish-brown and yellowish-white, respectively. For oak tree preservation in San Diego, integrated strategies of pest management are required to get rid of this disease.

Xylella Fastidiosa

This is a bacterial pathogen transmitted by vectors and associated with diseases in Oak and other trees. This bacterium creates colonies in the xylem networks of plants and blocks the vessels. Hence, water transport from root to leaves gets stopped, and eventually, the plant dies. Though in maximum cases plants are asymptomatic, some plants show wilting and leaf scorching.

Leaf Spot

This fungal disease interrupts photosynthesis and weakens trees. The disease affects a limited portion of the overall leaf area. If this leaf loss is found in 2 or more consecutive seasons, the tree growth is paused and susceptibility to pest-infected, and other diseases is increased. In this condition, tree preservation services in San Diego have to be taken, such as raking up and destroying fallen leaves of Oaks.

Sudden Oak Death

The plant pathogen, named Phytophthora ramorum, causes this disease that was first recognized by the death of Oak trees in California. You can identify infection of this pathogen with specific symptoms, like flagging, wilting of Shoot tips, and gradual loss of Oak leaves. So, to prevent this sudden death, potential tree preservation orders have to be taken by removing host trees and disposing of plant debris.

Oak Anthracnose

The fungus, Apiognomonia errabunda causes the disease in different species of Oak trees. Specifically, white oak trees are susceptible to this disease that generally creates minor damages to Oak landscapes. But if this infection continues for a prolonged period, severe damages occur. Leaves become shriveled or distorted and shed in a premature stage from its canopy.


Oak trees suffer from Hypoxylon canker with dead lesions on trunks, branches, and leaves of infected trees. The disease spreads from underlayers of barks. White rot decays are found in sapwood in the advanced stages. Symptoms of this fungal disease are thinning canopy, brownish-yellow leaves, reduced growth of twigs and Epicormic shoots on large limbs and trunks.

Powdery Mildews

White, grey patches or spots along with talcum-powder-like growth in oak trees indicate that the tree is suffering from Powdery Mildews. In case the spherical, tiny fruiting structures are seen in white color, then it becomes yellowish-brown and black in the final stage. You can find these spots on both sides of leaves, buds, and young stems. However, for controlling Powdery Mildews, effective oak tree preservation measures are the best thing to do.


Lichen growth can be found in tree branches and look like grey moss tufts or stringy patches. Though they do not kill plants, they cause poor health of plants. Lichen creates thick layers on trees, shade foliage of plants, and cover branches thoroughly. As a result, the photosynthesis of plants gets interrupted.


Most of the species of mistletoes parasitize their hosts and make abnormal growths, named as “witches’ brooms.” These pests deform tree branches and reduce the host’s reproductive ability. The only effective tree preservation order is complete parasite removal from host trees.