For those who live in Florida, Texas, California and other temperate locations, citrus trees offer a great variety of fruit that is nutritious and often very to grow. Still, citrus trees, like any other type of fruit tree, have their fair share of diseases with which to contend. Some of these will require the immediate destruction of the tree, and others can be dealt with by less severe measures.
There are two main causes of citrus tree disease---bacteria and fungus. Among the bacteria that can affect the trees, citrus canker is the most feared. Fungi such as melanose, greasy spot and sooty mold can also cause potential problems, but most are aesthetic in nature. Root rot, another type of fungus, can put the entire tree, or at least its production, in jeopardy.
In many cases, the type of disease can be identified by the marks it leaves on trees. Yellow halos on the fruit, twigs or leaves often indicate the appearance of canker. Melanose may appear as scabs on the fruit, particularly young grapefruit. Greasy spot and sooty mold leave spots and lesions on the leaves of citrus trees. Root rot is often identified by brownish patches on the tree's trunk as well as a liquid discharge.
Many citrus tree diseases, whether fungi or bacteria, have the ability to move very fast on a tree and from tree to tree. This is especially true of citrus canker. Those who have multiple citrus trees may find an infection on one means many others may also have the same infection. This helps in the treatment strategy, as they can all be treated the same.
In most cases, these citrus tree diseases are nothing more than parasites seeking a host to live off of. Although the end goal is not to kill or harm the tree, that may be what happens in the long run. Therefore, those who have trees with these afflictions, or suspect they may, action is important.
In most cases, preventing fungus on citrus trees can be difficult. Unlike apples, pears and other northern fruit trees, there is less of a dormant season because of cold temperatures. Therefore, using a fungicide in the spring may not be effective. Controlling insects can help keep sooty mold at bay. Thus, the only thing the citrus owner can do is monitor and keep any outbreaks as isolated as possible.
After an outbreak is noticed, the choices become more obvious. If it is a fungus, pruning and using a fungicide is often the best way to tackle the problem. If problem is citrus canker, it can be very hard to cure. In fact, some jurisdictions or states require immediate destruction of that tree and any citrus tree within a certain radius. For example, the rule is 1,900 feet in Florida. Further, Florida also restricts nurseries from selling trees located outside of 1,900 feet but within 3,800 feet of a canker discovery.