Olive mealybug (Euphyllura olivina) is a hemipteran insect that acts as a pest, attacking olive trees. This post will explain its life cycle and treatment, so you can learn how to reduce its population and control its infestations. I invite you to read on.
Olive Milkweed
This hemiptera Olive Milkweed is a small greenish insect of 2-3 millimeters, it belongs to the Psyllidae family, which likes to live near olive trees and, although it is considered a pest of olive trees, its damage is relatively serious, depending on how large the Olive Milkweed population is.
In the winter season, these insects are in their adult phase and are located at the bases of the leaves, axils and buds of olive trees. When the temperature begins to rise at the end of winter, it is when these hemiptera insects begin their reproductive activity. As it begins to reproduce, it lays its eggs on the underside of the leaves of the new shoots that are emerging. At the beginning of the spring season, their reproductive cycle begins and their first generation is conceived.
Around 30 days the larvae develop between the vegetative and floral shoots. During this process, the nymphs secrete a cottony substance, which is why they call it "Algodoncillo del Olivo", the cottony substance it secretes is the medium where they develop and grow. While their population is developing, colonies of these insects begin to form.
When the eggs hatch, the nymphs begin to feed on the new shoot, later moving to the flower buds and axillary buds. In the spring season the second generation of these insects is born, which occurs during the flowering of the olive tree. The larvae of the Olive Milkweed, develop and grow on the inflorescences.
Once this second generation of new Olive Milkweed has passed, and the adults go into rest. Until the autumn season arrives and a third generation of this insect begins to reproduce. This third generation is the one that least impacts the olive tree. Going unnoticed and not easily detected by the farmer. The Olive Milkweed plague is distributed throughout the olive-growing region of the Mediterranean.
Lifecycle
These small insects called Olive Milkweed, when adult measure 2 to 3 millimeters, are green in color and have a thick texture. Its 0,3-millimeter-sized eggs that have an elliptical shape, are white and then orange-yellow, due to their small size, it is not easy to see with the naked eye.
When placing the pupa, it secretes a white cottony substance that protects the larval crown. In their larval stage, the nymphs have a globular appearance and measure just 1 millimeter. In this phase it carries out 5 molts until its metamorphosis. At the beginning it is yellow and gradually changes to brown.
In their adult phase they hibernate during the winter season, they are located in the part of the armpit of the branch, which faces the trunk. At the beginning of the spring season and when the new leaves of the olive trees begin to sprout. Adult individuals of Olive Milkweed begin to start their reproductive cycle.
The reproductive cycle of the female olive moth ( Euphyllura olivina) begins with the laying of eggs on emerging leaf buds. These newly hatched nymphs feed on the sap of the olive tree. As the olive moth sucks the sap, it grows and forms dense colonies, covering itself with cotton-like filaments that protect the pupae or larvae. This first generation lasts approximately 30 days.
At the end of the first generation cycle, the second generation phase begins. This second generation is carried out on the inflorescences of the olive groves, this occurs during the spring-summer season. Then, in the fall, the third generation of Algodoncillo del Olivo begins, which is the one that least impacts the olive groves.
Phytosanitary Treatment of Olive Groves
As already mentioned, the Oligodoncillo hemiptera, is a pest that affects olive groves little, but aesthetically it takes away quality from plantations. The damage caused by these pests begins to be observed from the second generation when the adults begin to lay the eggs from which the new generations of Olive Milkweed emerge. When the colonies of these insects begin to form.
Sampling
When the next generation occurs, that is to say the second generation of Olive Milkweed, which are born on the inflorescences, and begin to cover with the silky white substance that the nymphs secrete, and which surround the inflorescences with their white filaments that seem cotton. Producing a great growth of its colonies that contribute to the fertilization of olive flowers, being deficient and consequently reducing the yields of the trees.
The attack of the Olive Milkweed is particularly aggressive in the flowering phase of the olive tree. Due to this, it is when a greater control of this pest has to be carried out, to carry out a population control treatment of the Olive Milkweed plague, it is advisable to carry out a sampling.
For this, a sample plot is chosen and a series of observations of the presence of insects in the inflorescences of olive plants is started. Observations must be made on the inflorescences and leaf buds to detect colonies of this pest. Sampling studies are carried out in plots of a size of about 300 ha., if the cultivar is of the same age throughout its extension.
If the presence of insect colonies has spread over the inflorescences of the olive groves, a phytosanitary treatment must be carried out. During sampling you have to observe how many insects attack each inflorescence. If you get to observe 8 insects per inflorescence, it means that this Olive Milkweed plague is at the threshold of infestation. It is when you have to start a control of these insects.
So far no preventive treatment is known, what is known is that the abundance in the attack of these insects on the inflorescence is associated with the weather. What can be done is to carry out preventive treatments with potassium soap at the beginning of the spring and summer seasons, to see if the populations of the Olivo Algodoncillo hemiptera are controlled. Also, water the branches of these trees well.
Although the impact of these hemiptera insects on olive groves is insignificant, what is affected is the nutrition of olive trees. The infestation is worrying if its population increases because the suction of the saps of these trees will lead to the paralysis of the emergence of flower buds and their transformation into olive fruits. In addition, the functioning of the physiology of each tree in terms of photosynthesis and olive stain.
Phytosanitary treatment
As previously mentioned, the phytosanitary treatment begins after prior sampling of the olive groves. It should be noted that, based on the reported data regarding the Olive Milkweed population, the phytosanitary treatment will begin on the olive grove inflorescences. It has been observed that a greater number of Olive Milkweed colonies are detected during periods of low rainfall. Conversely, when rainfall is very high, the rainwater washes away the inflorescences and consequently eliminates the Euphyllura olivina colonies.
The phytosanitary control of this plague can be carried out with potassium soap. This treatment with this soap does not affect the morphology of the inflorescences of the olive groves, nor the quality of the fruits. After treatment with potassium soap, a mechanical treatment is carried out to help destroy the surface layer that protects these insects.
To keep the proliferation of this pest down and control the attack of the flower buds and the absorption of the sap, the control is carried out with: Dimethoate, which is sprayed on the cottony substance that generates the Olive Milkweed pest, on the inflorescences. This product must be applied before the flower buds open.
If dimethoate is applied after flowering, it will help save the table olive harvest, as post-flowering infestations negatively impact fruit quality. Biological control is achieved using natural enemies such as hoverflies, lacewings, and the parasitic insect Encyrtus euphyllurae.
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