Question: olive tree with stained leaves
Good morning, I would like to know how to cure my olive plant that has dark spots
and numerous on the leaves. They told me they should be called peacock eye. I thank you in advance for the answer you will want to give me and I send you my best regards.
Answer: olive with stained leaves
the peacock eye is a fungal disease that affects olive trees, very present on the Italian territory, although many new varieties of olive are quite resistant to this type of pathology; the spots are well distinguishable from other types of pathology, such as oidium or scab, as with the passage of time they differ in concentric circles: first we will have gray spots, with on the outer perimeter a black circumference; in summer, when the climate becomes warm and dry, they form yellow halos outside. The common name of this pathology derives from the similarity between the spots on the leaves and the so-called "eyes" that can be seen on the tail of the male peacock.
So, if you think it's peacock's eye, or if it was suggested to you by someone who has seen the leaves of your olive tree, I think this is really this mushroom, given the unequivocal appearance of the symptoms.
In general, this type of pathology is worrying only when the olive tree is part of an olive grove, from which the olives are taken to obtain the oil, or to sell them for other reasons; as this type of fungus, although ruining many leaves and many fruits, hardly causes irreparable damage to the plant.
Surely treatments against the peacock eye work better as prevention, rather than as cures to eradicate the disease, since once a leaf has been struck (or a fruit) it is very difficult to make the leaf healthy again; in general, instead, products are used which will cause the damaged leaves to fall, stimulating the plant to produce new ones. These products are based on copper, generally as copper oxychloride; this type of treatment is done in spring, early in the season, as a prevention for the following months, or in autumn, as a prevention for the following year. In your case I think it is late for a copper-based treatment, try asking in the nursery if they have any products against fungal diseases that can be used even in late spring.
Surely the spring of 2012 was decidedly inclement towards plants: low minimum temperatures and frequent rains, in fact stimulate the proliferation of fungal diseases, which therefore attack plants more likely.
Other risk factors for the peacock eye are certainly the use of nitrogen fertilizers in excessive quantities; and also an incorrect pruning: the leaves that are well lit by the light of the sun, and that therefore dry up quickly after the rain, tend to fall ill with less probability; so next year remember to practice good pruning, which will air the hair well.