Olive trees have significant commercial value. These trees are grown for their fruits, their leaves, and for the oil that they produce. Olives are nutritious fruits that are associated with various health benefits. The olive leaf is known to contain a natural extract that can help to regulate blood pressure without the side effects associated with the use of pharmaceutical drugs for the same. This article discusses three diseases that commonly affect olive trees for the benefit of commercial olive tree growers.

The Olive Knot

Olive knot is a bacterial infection, and it is among the most commonly occurring diseases on olive trees. An affected olive tree will have knots or galls at various infection sites. Leaf nodes are the most common infection site, and they should be the first place to check when looking for signs of this disease. Knots may also form on twigs and stems of the olive tree.

Olive knot is a dangerous disease because it introduces plant growth regulators into the affected site on the tree. The knots can easily kill affected twigs and affected areas of the olive stem by interfering with the supply of nutrients to the mentioned areas.

When it rains, the galls on a sick olive tree ooze bacteria. The bacterial ooze is contagious and it can lead to the development of knots on previously uninfected parts of the plant.

Leaf Spot

Leaf spot is often responsible for a yellow or whitish appearance on the leaves of an olive tree. Affected trees may also have their leaves covered in a fungus, which looks like a cover of black dust on the underside of the olive leaf. An olive tree with leaf spots will have its leaves (and often fruits) falling prematurely.

Leaf spot on olive trees can be controlled by pruning the affected leaves and the branches attached to these leaves.

Fruit Mummification

Fruit mummification refers to a situation in which brown lesions occur on the skin of the olive fruit. These lesions expand and they can easily take over the entire surface of the fruits' skin.

Fruit mummification is a fungal infection whose spread is encouraged by the availability of water and the occurrence of humid conditions. Affected olive trees will have highly acidic oil upon extraction and the fruit yield from such trees will be significantly lower.

The application of fungicides before the rains set in can help to reduce the likelihood of fruit mummification on olive trees.

Don't hesitate to call in the tree consultant if any of the above diseases are positively identified on an olive tree.