Olive knot is a plant disease caused by the bacterium Pseudomonas savastanoi. It primarily affects olive trees, causing the formation of rough, gall-like swellings or knots on the branches, twigs, and sometimes on the fruits themselves. These knots can range in size from small bumps to larger, irregular-shaped growths. Here are some symptoms of olive knot to look out for:
- Knots or galls: The most common symptom of olive knot is the formation of knots or galls on the olive tree. These knots can be green at first but eventually turn brown or black. They may appear as rough, irregular growths on the branches, twigs, or even on the fruit.
- Swollen and distorted branches: Infected branches may become swollen, distorted, or develop a knotty appearance. The knots can vary in size and shape, and they may cause the affected branches to become stunted or weakened.
- Gummy exudate: In some cases, you may notice a gummy exudate or ooze coming from the knots. This sticky substance is a combination of bacterial cells and plant sap and is often visible on the surface of the knots.
- Leaf and fruit damage: Olive knot can also affect the leaves and fruits of the tree. Infected leaves may exhibit yellowing, wilting, or browning. The fruits may develop lesions or show signs of rotting.
- Reduced productivity: Severe infestations of olive knot can lead to a decrease in olive production. The knots and associated damage can weaken the tree and inhibit its ability to produce healthy fruit.
If you suspect olive knot infection in your olive trees, it is advisable to consult with a professional arborist or agricultural extension service for an accurate diagnosis and appropriate management strategies. They can provide specific recommendations for treatment or control measures based on your particular situation.
