One of the pests that most affects the olive tree is the olive milkweed. Its scientific name is Euphyllura olivine and it is a homopter that, although it does not usually cause significant damage, is quite annoying when harvesting olives.
In this article we are going to tell you all the characteristics, biological cycle and treatment of olive milkweed. Learn how to prevent this pest.
The olive milkweed is a homoptera that belongs to the Psyllidae family and its presence in olive trees is quite frequent. Despite what you may think about this plague, it does not usually cause serious damage. These insects normally spend most of the winter in their adult form. To be able to find those inside the trees we must look at the base of the leaves, axils and buds.
At the end of winter, as temperatures rise, they begin their activity. It is when spring arrives where they begin to generate their first generation. They take about a month and develop between vegetative shoots and flower buds. Nymphs are responsible for secreting a cottony substancewhich hence receives the name of olive milkweed. This cottony substance is used as a medium to grow and develop.
Once they have established their growth, it gives rise to small colonies that form a kind of plague. The second generation of spring occurs at the time of the flowering of the olive tree. In this case, they develop on the inflorescences and the others, giving rise to a cottony-looking colony. This second generation reaches adulthood in summer. If the fall is not very hot, start a third generation during the fall stage. However, this generation tends to go more unnoticed and is more difficult to recognize with the naked eye.
Life cycle of olive milkweed
These insects are usually very small in size although they have a thicker texture and a green hue. Eggs can be recognized as they have an elliptical shape. The eggs are very small so you have to look for them carefully. When they are in the larval stage, they secrete a white wax that helps to cover an area called the larval crown. This plant area has a cotton look and is what gives the pest its name.
The insects that belong to this pest they usually remain in adulthood during the winter. It is here that we can already emphasize eliminating them so that the pest does not have a next generation in the spring time. To find them we must look in the part of the branch that is left with the trunk, where refugees are normally found. With the spring and the flowering of the olive tree its biological activity begins.
At this time the females begin their reproductive cycle and lay eggs on the shoots of the olives. The food of the nymphs that are newly born is the sap that the olive tree produces. To feed they suck the sap and gradually form a very clustered colony and are held together through these cottony texture filaments.
The first generation of these insects has a life cycle of approximately one month. The second generation is the one that will give way to the adult stage of the insect. With the high temperatures of the summer it ceases its activity and begins a brief rest that lasts until the beginning of autumn. If the fall is not too hot there will be a third generation. This third generation is not given much importance since it does not have very negative effects on the olive tree.
Symptoms and damage
As we have mentioned before, the damage caused by this pest is not too serious to take into account. The concern about the appearance of the colonies is more than the damage they cause. It must be taken into account that during the second generation, when they are adults, is when they can present some more important problems. And it is that the milkweed-like colonies are quite numerous in this generation and they become very dense around the inflorescences. This excess of colonies can lead to poor fertilization of the olive tree flowers and harm the production of olives.
The critical period for this pest is the flowering of the olive tree. It is then where we must be more attentive to eliminate these insects. To recognize the symptoms we must carry out a sampling period before the start of flowering. We select a sampling plot and it will be necessary to see if the colonies are appreciated in the places close to the shoots. If the cultivation of the olive tree is homogeneous, it is enough to choose a plot of 300ha.
If the colonies are very dense, they will have to be dealt with. The same happens if they are very numerous. The action threshold is located from 8 insects per inflorescence. From here is where you have to carry out an intervention.
Olive milkweed treatment
Since the and very clear prevention measures we only have to carry out the aforementioned sampling. And this to the development of the populations of these insects saw very conditioned by the weather. The years that have less rainfall are those that favor a greater development of the olive milkweed. On the other hand, abundant rains are responsible for eliminating a large number of nymphs.
Since from 8 insects per inflorescence can end photosynthesis and the generation of olive fruit must act on this pest. The chemical treatment must be based on authorized phytosanitary products. One of the most commonly used chemicals for treating olive milkweed is this potassium soap. It is a registered chemical product that does not cause any biological change in the appearance or shape of the fruits. It also does not create resistance to have a mechanical operating effect and helps to destroy the protective coating of insects.
As you can see, it is a pest to which you have to pay some attention as long as it is visually abundant. I hope that with this information you can treat olive milkweed.