It is a secondary level pest in the olive grove, the violet scale ( Parlatoria oleae Colvée, 1880) is also known by the common name violet louse. Its presence does not usually present major problems, although in olive groves destined for greening, the application of control treatments may be necessary.
His attacks are less frequent than those of his “sister” black scale olive tree (Saissetia oleae).
Damage caused by the violet scale
The violet scale does not secrete molasses when feeding, so that its activity does not favor the appearance of the fungus of the bold of the olive tree or fumagina.
However, this scale produces spots on the skin and deformations of the fruit with the consequent devaluation of the crop.
The olive may suffer a certain reduction of fat yield.
Although it is still a pest that feeds on the olive tree and it is necessary to keep it under control. If the infestation levels are low, their presence is controlled by other predatory insects (especially the parasite Aphitis Sp) and their activity is barely noticeable.
Biological cycle of Parlatoria oleae
Parlatoria oleae has two annual generations, the first feeds on the olive stems and leaves. On the contrary, the second generation feeds and produces damage to the fruit.
It is initiated by the fertilized females that have spent the winter. They usually deposit from 30 to 100 eggs in the month of March. In April the first nymphs appear and in May the population peak occurs. Females usually feed on stems and leaf mayos.
It develops at the end of summer and the violet scale has a preference for the fruits of the olive tree.
Control and treatment of Parlatoria oleae
There are several measures that can be used to keep acceptable levels the populations of violet Parlatoria oleae.
Cultural measures against scale
The temperatures above 32 degrees are the main ally against the violet scale. In summer, adults seek refuge on the north side of the tree and prefer olive trees with a very dense crown. The thinning pruning , allows the correct aeration of the olive tree and is A good way to control scale.
Control by parasitic insects
The populations of the parasite Aphitis Sp usually keep violet scale levels at bay. However, a bad use of insecticides can eliminate a large part of these parasites and cause a natural imbalance.
Treatments against this Parlatoria oleae
You may be interested in its realization in olive plantations for greening where the previous campaign found an excessive level of fruits damaged by violet scale. The treatment is done by applying to the insecticide olive tree in May to control the presence of the first generation of Parlatoria oleae.
You may also be interested in the following articles on olive diseases:
Varieties resistant to wilt olive tree.
Identification of olive tree borer.
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.