It is an annual plague, and it is known how and when it arrives. The processionary caterpillar creates numerous headaches each year in February and March for pet owners, especially dogs, with episodes that lead to visits to the emergency room and, in some cases, admissions for several days to alleviate the effects of poisoning suffered by these domestic animals. This year, the traditional elimination of the pockets of processionaries in the tops of the pine trees has not reached all the parks in Zaragoza, and numerous emergency episodes have been recorded among pets due to direct contact of the snout and tongue with the caterpillar or the dry needles partially gnawed by the worm and pine tree falls.
Ana Reinales lives in the neighborhood of La Jota, and has had a bad time these days with her pet Kayla. “I have had dogs all my life; next to my house there are many pine trees, and we know that you always have to be careful at this time when you walk the animals, but if the processionary bags are eliminated in time, the danger disappears. A few years ago we already had a bad time with a Belgian shepherd, but it was not a severe case, it was strong. Now I have two dogs, a two-year-old mongrel called Laika and a five-month-old Yorkshire puppy, Kayla, who is more active. Poor she touched the bug with her snout and immediately I saw that something was happening to her through her gestures. Although we rushed to the vet to get the medication on duty, the poison reached her tongue and it became partially necrotic on the tip and sides; my dog has lost a piece of her tongue because of the processionary”.
Kayla has been admitted to Valvet Valdespartera for three days. “The treatment has been splendid, they are great professionals. They have had it with drippers; We didn’t know if she had swallowed poison, that would have affected her stomach. She has recovered, but not completely; she is not well yet. The City Council used to remove the nests, but this year it has not been done or not enough, they tell me that it passes through other parts of the city. Here next door, in the Parque de Oriente, there are also nests. I am going to denounce this fact; I expect solutions, and it’s not a question of money, although obviously that extra cost of hospitalization of the animal does not come in handy to anyone”.
Complaints about problems derived from the processionary in pets extend to the university campus of Plaza San Francisco, Parque Grande, Juslibol and other parts of the city. “It is also dangerous for small children, who still cannot know the danger that these little worms pose,” a citizen pointed out by telephone in a call to this newspaper.
The scientific name of the so-called pine processionary is Thaumetopoea pityocampa. It is a common lepidoptera in the pine forests of southern Europe, especially in the Mediterranean area, and its presence is classified as a plague. It also appears punctually in cedars and firs. These caterpillars are covered with stinging hairs that break off and float in the air, causing irritation to the ears, nose and throat in humans, as well as allergic reactions. The toxin they release is Thaumatopin.
Veterinarian Montxo Ferrández, from the Zaragoza clinic Pelos, Plumas y Escamas, clarifies that this problem is more common in younger and more curious dogs. “They smell and lick everything, and it mainly affects the mouth, lips and tongue. This contact becomes dangerous if the caterpillar’s stinging hairs, which are like pins, go down the throat and obstruct the airways. Preventing these episodes is a matter of care: if you walk among pine trees at this time of year, especially when the temperature has changed towards more temperate levels, you must lead the dog on a short and controlled leash. Nests in pines are also easily seen. The dog gives clear signs of alarm: normally they start to drool a lot, to kick their feet in their mouths… you have to see if they are breathing well and if not, run to the emergency room”.
Ferrández also recommends home remedies for cases where there is no respiratory problem. “You can give them water with a hose or shower-type sprayer, or by tilting a bottle, but always without rubbing, because that would release the toxic substance that is in the stinging hairs; on the back of the worm, between each segment, a small bag that releases thousands of microneedles and causes poisoning. It is better for the dog to look at the ground when he is given water, so that he does not swallow any hair of the caterpillar that he may have in his mouth. In the emergency room they are given a powerful anti-inflammatory and antihistamine; This way you can alleviate the pain. Unfortunately, if there are a lot of caterpillar hairs in the dog’s mouth, it’s not uncommon for a piece of the tongue to fall out through necrosis; if that piece is not very large, they do not lose quality of life, but if it is, it costs the poor a little more to recover and eat or drink normally, even if they end up dealing with the problem”.
The veterinarian points out that “the first days or even weeks after the episode they cannot eat well, so those days You have to feed it carefully and make sure it doesn’t get dehydrated. The day before yesterday the last case came to me, a month and a half puppy from Botorrita; in the house they did not have caterpillars on the pine trees because they had been eliminated, but the neighbor did… and the caterpillars ended up falling to the adjoining land”.
From the Green Unit
Alberto Esteban is the head of the Zaragoza Green Unit, attached to the Parks, Gardens and Green Infrastructures service. This unit deals with various tasks, from the control and surveillance of the natural environment to the detection of illegal waste, the rescue of animals or the preparation of bird censuses. “The adults of this caterpillar, from a specific date that usually coincides with the month of June, fly like butterflies and live for about a week and a half; It is then that they lay their eggs in the high branches of the pine trees; they are planted on the needles of pine needles and make a kind of pod or hive. From then on, when September or October arrives, the little worms are born and go through five stages”.
The first three growth stages are not dangerous. “They can last from 20 to 30 days each -explains Esteban- and there the caterpillars do not create problems even if there is contact. In December they pass to a fourth stage and immediately after to the fifth, already with a considerable size, there it is not perceived as a problem, small bags. From December, the fourth instar and then the fifth, when they reach a considerable size – ranging from three to five centimeters, and the females are larger – with the most visible pockets, which serve to protect them from the cold at night. When the temperature improves, they go out and that is when they become a problem; they feed on the needles of the leaves of the pinaceae, but from February the processions of descending the trunk of the tree begin. That’s why they’re called that.”
The objective of this caterpillar is to bury itself in the leaf litter and transform into a pupa, the previous step to the chrysalis and the conversion into a butterfly. “Sometimes this transformation is not done in the same year, it remains as a pupa and is buried for a second year, and the process is repeated. As for the trees, they collaborate in their defoliation and create more problems for them to survive, even if they are not the ones that end up killing them; yes they can open the way to borers that finish the task. If this is not the case, the leaf comes out again, especially in the Zaragoza Aleppo pine. Before using insecticides, it is effective to remove the bags or use other resources, such as nest boxes. If the bags are few, they must be removed and burned in safe places; if there are many, a ring-trap that catches the caterpillars lowers the procession down the trunk works well”.
The trap is a kind of collar that sticks to the trunk of the tree, and has a downspout connected to a plastic bag filled with soil from the area; when the procession of caterpillars arrives, they take that downspout and voluntarily enter the plastic bag with soil to bury themselves and start their metamorphosis. This trap reproduces the conditions that processionary larvae seek to complete their biological cycle. In addition, it is reusable and can be stored for the next season after washing its main elements with soap.