Caused by the bacterial pathogen, Pseudomonas savast anoi pv. Savast anoi (Psv) olive knot disease has a long history in California. Over the past decade this disease has become more common and serious.
Infection can girdle and kill affected twigs, reduce yields, and have a negative impact on fruit size and quality. Severe symptoms can also reduce the aesthetics of olive trees used in landscapes.
The pathogen can be spread in several ways including: windblown rain, contaminated pruning tools or infected nursery stock. The bacterium can enter into the plant through natural openings such as leaf drop, through wounds resulting from frost injury or hail damage, or through wounds caused by cultural practices such as pruning and harvesting.
Find out more about this disease and how to take steps to reduce its spread from UC’s Olive Knot Pest Note.
