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Processionary Danger

enero 12, 2021


With the arrival of spring, the walks, the moments of outdoor play with our friends increase, and when possible we leave the home to seek sun and a mild climate.

At this moment, however, we need to be able to identify what are the best and safest places for recreation for us and our friends. This period of the year in fact represents the main moment of diffusion of the processionary. It is an insect, whose scientific name is Thaumenotopoea pityocampa and is one of the most dangerous and destructive: for forests, as, during its biological cycle, it is capable of stripping large tracts of forest and trees of every leaf. pine and cedar and for animals and humans, as during its larval stage it has a down that is stinging and irritating.

The life cycle of these insects is divided into four stages:

  • egg;
  • larva or caterpillar;
  • chrysalis;
  • butterfly, which corresponds to the adult form.

The females of this insect, at the end of the summer season (July-August), they lay their eggs on the pines, from which the larvae then emerge. In this particular period of the year, the vegetative regrowth of these plants takes place and the larvae, born between August and September, exploit this condition for their growth, feeding on the newly emitted leaves, causing damage to the plant. At this point the larvae reunite with each other, creating ever larger and more recognizable nests on the branches.

The «nests», which are easily identifiable and attributable to processionary, they have the appearance of a filamentous “skein” of greyish white color preferentially located at the level of the joints of the branches and at their attachment. Looking at it absently, it looks like a white spider web.

During the winter the larvae remain in their nest, thus protecting themselves from the cold, low temperatures and staying close to each other. When winter ends and spring appears, the temperature becomes milder and the larvae can come out of the nests. This is the moment in which they begin to move according to their characteristic single file pattern, arranging one after the other, so much so as to recall a procession (this is where its name derives from). The larval stage is therefore the most dangerous for humans and animals. It is at this stage that the insects have a brown red color, with a very hairy body and whose hairs are very irritating and stinging. This particular aspect of the insect causes it to be also called «hairy cat». At the end of the summer, from the larva stage the processionary then passes to that of chrysalis and finally to adult, represented by a triangular butterfly, nocturnal, yellowish white in color. This can only release an irritating liquid if it feels threatened. Here is how the cycle begins again.

This insect, in its larval form, it is particularly dangerous for our dog friends that, continually sniffing on the ground, and being very intrigued by these insects that walk in procession, can come into contact with, or worse, ingest, the stinging hairs that cover the body of the processionary. It should in fact be emphasized that i stinging hairs of the processionary moth can easily detach from the caterpillar itself, and can therefore be dispersed by the action of the wind. The hairs of the processionary moth, once in contact with the skin, easily inflict on it and are responsible for erythematous reactions, with the formation of very itchy papules. A contact with these hairs can therefore be deleterious for our friend, but this is not the most serious event.

It will turn out in fact, contact with eyes, mouth, mucous membranes in general, and obviously ingestion or inhalation, is much more dangerous. In the latter cases, the clinical signs will be much more severe. We will first find sialorrhea, that is, increased salivation due to an inflammatory process, which has established itself in the mouth. The tongue begins to redden and vigorously increase in volume. This condition worsens in a short time, leading to a progressive and continuous swelling of the same so as to risk causing breathing problems in our friend. Combined with this, the direct contact of the stinging hairs of the processionary moth with our friend’s tongue causes cell damage which can be so extensive as to establish necrotic and irreversible processes, associated with the loss of more or less extended parts of the tongue. It is easy for us owners, in these circumstances, to understand that we are facing a serious state of emergency.

Others symptoms that can be found are: loss of vivacity, vomiting, refusal of food and finally diarrhea, sometimes even hemorrhagic. It is therefore evident that these damages, due to their extreme speed and aggression, are extremely serious and require urgent care for our four-legged friend. Although the cases are limited, it can also happen that the hairs of the insect in the larval state, being poisonous, can induce a very serious allergic reaction in our friend.

Ultimately, therefore, in the event of a direct encounter and interaction with the processionary moth or with its hairs released into the environment, the signs are so striking and serious that they do not raise doubts about the immediate need to take our friend to the doctor, so that he can be treated in the fastest and most timely manner. The earlier you manage to intervene, the more you can limit the permanent damage that this unpleasant encounter will cause.

What can be done to prevent this serious inconvenience and avoid the serious damage caused by the processionary moth is: do not touch processionary nests or the caterpillar itself, but conversely, get away as quickly as possible after spotting an infested plant. The morphology of the nest but also of the insect in the larval stage are so simple to identify that, once we have learned to recognize them, we can no longer have doubts.

Finally, it should be emphasized that contact with this insect is also harmful for humans. These insects can cause in humans, again due to stinging hairs, reactions such as:

  • stinging reaction induced by the release of histamine;
  • painful rash with intense itching;
  • conjunctivitis in case of contact with the eyes, associated with redness and pain in the eyes;
  • irritation of the respiratory tract in case of inhalation;
  • inflammation of the mucous membranes of the mouth and intestines, accompanied by intense salivation, vomiting and abdominal pain, in case of ingestion.

We are all anxiously awaiting the beautiful days, the sun and the fun with our friends, and a few simple precautions will be enough to live these moments of joy, with serenity.