Olive trees, native to the Mediterranean area, parts of Asia and parts of Africa, can now be found all over the world. As the demand for olive products has increased, so has the need to protect the trees from fungi and pests that threaten their crop. Fruit flies and infections that cause wilting and knots are the most prevalent afflictions of olive trees.
Mediterranean Fruit Fly
Characterised by a black thorax with silver markings, a tan abdomen and clear wings with two brown stripes, Mediterranean fruit flies thrive throughout the world. Mediterranean fruit flies lay their eggs under the olives' skin. After hatching, the larvae feed on the fruit for about six to 11 days. When the larvae leave the olives they have inhabited, the fruit is ruined.
Olive Fruit Fly
A mature olive fruit fly has a brown thorax, head and abdomen with markings in a darker colour. Yellow or white patches appear on its thorax and black spots occur on its wing tips. A female olive fruit fly has a pointed structure at the end of its abdomen to puncture olives and then lay its eggs. As fruit fly offspring feed on the olives, other bacteria infect the fruit.
A soil-inhabiting fungus causes verticillium wilt. The fungus attacks olive trees through natural wounds in the root system, then spreads upward through spores.Verticillium wilt causes chronic symptoms such as small, yellow foliage, leaf scorch or browning, slow growth, abnormally heavy seed crops and dieback of shoots and branches. Acute symptoms include curling, drying leaves, abnormal red or yellow colouring, partial defoliation, wilting and branch dieback.
Olive knot is a bacterial infection brought on by the use of infected pruning tools during the rainy months. It's characterised by swelling on the tree branches, leaves and trunk. To prevent infection, use a fungicide to stop bacteria from entering through tree wounds. Disinfecting pruning equipment and carefully pruning trees during the dry season are other preventive measures.