The sooty mould is one of the diseases or pests that can suffer the olive tree.
In Spain this disease is also commonly known as tizne or fumagina.
The sooty mould is the cause of the performance of several fungi, among which the genera Capnodium spp and Limacinula spp.
Together with these, the saprophytes Aureobasidium spp, Alternaria spp and Cladosporium spp can be developed, among others.
In order for previous fungi to proliferate, they need as sugary compounds and moisture to develop. The olive molasses is an ideal place where they can develop.
The production of olive molasses is the residue (excrement) resulting from the feeding of the black scale olive tree (Saissetia oleae). This sap-sucking insect is also known as tizne mealybug, for being the main trigger of this disease.
Although the main producer of molasses is black scale, the olive tree itself can also exude molasses in stressful situations. Although it is rare and has little relevance.
Also the citrus fruits are affected by the black scale initially and finally by the fungus, commonly called orange bold.
Damage caused by the sooty mould in olive tree
The sooty mould in olive tree does not cause direct damage to the leaves. However, the fungus forms a black layer or film on the leaf. This situation prevents the correct realization of photosynthesis by the olive tree and causes weakening.
The fungus also adheres to the branches and fruits. The farmer suffers two damages, a direct one that is the devaluation of the green olives affected by the Negrilla. And an indirect one due to the decay of the vigor of the olive tree, which can see its productive capacity limited.
Mushroom of the sooty mould treatment
The main is treatment measures against the occurrence in the olive tree of the sooty mould mushroom, tizne or fumagina is the control of black scale populations.
The black scale olive tree control can be:
Natural (predation or food of parasitic insects).
Cultural measures (mainly aeration or thinning pruning).
Phytosanitary treatments (if there is no other choice, we will apply insecticide) .
Once controlled the black scale, the treatment against the fungus of the sooty mould may be necessary, for which various fungicidal products (mainly derivatives) can be used of copper or sulfur salts).
To learn about phytosanitary treatments and products authorized by the ministry to eliminate or control the sooty mould of the olive tree, we can access the Register of Phytosanitary Products of the Ministry of Agriculture, Food and Environment .
Sooty mould resistant olive varieties
In Italy it is more common that the conditions for the proliferation of the sooty mould fungus occur.
Therefore, the olive resistance levels against the disease have been studied.
They have sooty mould resistance: Ascolana Tenera, Tonda di Cagliari, Pignolo.
neutral behavior against the tizne fungus: Bosana, Rotondella, Carboncella, Pisciottana, Borgiona.
They have medium-high sensitivity to the fumagina: Leccino, Pendolino, Belize zipper, Sant’Agostino, Cellina di Nardo, Cerignola.
Recommended reading
Control of verticillium in olive tree.
Information about the Olive tree borer.
Warning
We have translated the information on our website from Spanish to English. Note that some words may have seen their meaning altered during their translation.