The olive bud mite, also known as erinosis is produced by at least four species of erythroids.
Within the mites (Acarina) of the Eriophydae family we can find in the olive tree the following species: Aceria oleae (Nalepa, 1900) Aculus olearius, Ditrymacus athiasellus and Oxycenus maxwelli.
Similar in appearance, they have vermiform shape with a ringed structure. Its size is very small, between 100-350 micrometers, being necessary the use of the microscope for viewing.
They are of light color (varying from white to orange ) and only have two pairs of legs, located in the front.
Biological cycle or stages of olive bud mite
Stages of multiplication: the olive bud mite develops especially during the spring and in a smaller way in autumn. In May there is the highest incidence of this pest.
Food: The olive tree eriophs feed primarily on the young shoots. Therefore, the period of greatest growth of the olive tree is the most affected by the erythroid mites that produce the erinosis of the olive tree. The colonies of mites are located on buds, beam and underside of the tender leaves of the olive tree.
During the flowering of the olive, the mites feed on the floral corsages >causing significant deformations in olives.
From June, the mite populations descend rapidly until they rebound with the autumn sprouting of the olive tree.
Winter takes its toll on mite populations. Some manage to survive the winter by placing themselves in the yolks of the olive tree. These mites are the ones that begin the cycle in spring giving rise to the new colonies of eryphids.
Treatment against olive bud mite
The olive bud mite is a secondary pest usually with little incidence on the olive crop.
The climate factor is probably the most decisive in the control of the Oxycenus maxwelli of the olive tree.
In most olive groves, treatments against Eriophyid mites are not necessary and the climate is responsible for controlling populations.
Heavy rains and extreme temperatures of heat in summer and cold in winter, manage to control the populations.
Natural enemies biological control
Eriophyid mites causing olive tree acariosis have other mites as natural enemies.
Neoseiulus californicus is a mite phytoseido that is grown industrially and can now be found in application containers.
Another phytoseido is Typhlodromus sp and within stigmeids, Zetzellia sp also helps in the control of olive bud mite.
Some olive varieties are more sensitive to Eriophyid mites.
For example, in my growing area, the leaves and olives of the variety Verdial de Badajoz are usually affected, however Manzanilla Cacereña hardly shows any symptoms.
It may be necessary to apply treatments on small seedlings or farms dedicated to verdeo (when it causes significant economic damage).
We must ensure that the seedlings present in the nursery are disease free. If virulent symptoms are detected we can make applications at the beginning of spring (March) or in autumn.
In the case of the olive grove the treatment is done during flowering to prevent the mites from producing deformations in the fruits.
In case of need of treatment sulfur and abamectin are the products commonly used. Before performing any phytosanitary treatment we must ensure that it is authorized by the ministry.
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