The fungus Omphalotus Olearious Singer, is an illness that appears in irrigated olive orchards. The attacked trees are rotting and get completely destroyed. A very costly, but very effective way to face this fungus is to destroy the effected tree and disinfect the soil.
The fungus Cycloconium oleaginum Cast. is the most serious disease of the olive tree. The damages depend on the place, the variety and the time.
The effect takes place on the top surface of the leaf and seldom on the bottom, because the bottom is covered with fuzz, that makes the establishment of the fungus difficult. Round spots appear on the leaves 1cm diameter. The effected leaves fall early and that leads in sterile branches.
The fungus grows in temperatures of 10C and 20C and needs high moisture. For the tree to get infected, the leaves should be wet for several hours.
The fungus gets into the leaf to secure its nutrition, resides there all summer, and then enters the period of its fruition with the first showers.
In a warm, moist climate, the infection from this fungus can happen twice a year. We have leaves falling in the summer from a spring infection, and in the winter from a fall infection.
To stop the expansion of this fungus, we spray the olive tree with chloride acidic copper. A second spraying should be done with an adherent, which is going to preserve the fungus’s eliminating components, in the beginning of the fall and in the beginning of the spring, or after the pruning at the end of the winter, so they don’t get washed out from the rains.
Because moisture is the main reason for the appearance of this fungus, we should drain well the moist soils and prune the trees, so the tree gets aired out and no drops of moisture stays on.
Another kind of spraying is with Captan, which destroys this fungus. When the leaves fall on the ground, they lose their contaminating ability and the olive tree can not get infected.
Another fungus is the Macrophoma (Phoma) dalmatica. It is a very serious disease of the olive fruit.
The fungus gets in the olives from the wounds, that Dacos left. It gets under the skin, with the help of the atmospheric moisture. The ripe olives rot and the unripe fall on the ground. The varieties for table olives lose their trading value and the varieties for olive oil lose their virginity. Extra virgin olive oil, is no longer an option.
The fungus Cercospora cladosporioides Sacc. is well known in the Mediterranean countries. Spots appear on the leaves, which in many occasions cover them completely, which results in the death of the leaves. The naked branches slow down the growth of the olive tree. The best way to fight this fungus is with spraying in the spring and in the fall.
The fungus Polysporus spp., Polystictus spp., Fomes spp., Porta spp., Stereum spp. and Irpex spp., are fungus, that appear on the trunk and branches of older olive trees and often attack the roots. When the roots get attacked, the olive trees die. All these fungus get into the olive trees from the wounds of the pruning and develop easier where the rain water gathers. The olive trees develop cavities in the trunk, the wood dries out, with result in the death of the trees.
The fungus Leveillula tautica Arn. attacks also the leaves of the olive tree. The fighting against it, is done with sulphurism and even better with Ferinamol and Benomil which are circulating in the fluids of the olive tree and prevent the growing of the fungus.
The Phoma incopta Sacc., is a fungus that attacks 2-3 year old branches and continues with the older ones. Leaves and olives get dark brown spots. To fight this fungus Chlortalomil and Dithiason are used.
The Rhizoctonia ssp., Fusarium spp. and Pythium spp., is fungus that attack the very young olive trees. The fight against this fungus is costly, because the disinfection of the ground is required.
The fight against fungus should be done regularly. The production of extra virgin olive oil and top quality table olives, demands a healthy olive tree.