It was in June 2017 when the destructive power of the subterranean termite (Reticulitermes flavipes), an insect that had already caused significant damage in designated areas of Tenerife, mainly in the municipality of Tacoronte, where its presence dates back at least to 2009, the date on which it was detected for the first time in the Parque Atlántico residential area.
Much has happened since then. Research, treatments, information to citizens, public support, awareness and a plan for its eradication, have made the Reticulitermes flavipes It will go from being a nightmare to a reality that must be lived with, supposedly controlled, and from the next five years, a bad memory if all the provisions are met to completely extinguish it.
The main consequence of all this is that Tenerife is currently a world leader in the eradication of this insect, which has found optimal agroclimatic conditions on the island that have facilitated its reproduction and spread, becoming one of the places in the world with larger treated surface.
A control and eradication plan has already been approved and on November 22 an international congress will be held in Tenerife in which experts from the United States, Canada, Chile, Great Britain, Switzerland and Portugal will participate, who will contribute their experience in other regions and will be able to observe , first hand, how this novel treatment is being carried out.
This is stated by the researcher and biologist of the Institute of Natural Products and Agrobiology (IPNA-CSIC), David Hernández Teixidor, who adds that many sites “reticulitermes populations are controlled so that the damage is reduced and they can live with them, while on the island it has been decided to try to eradicate them, so all the treatments that we are going to doing eliminate colonies until the known surface with subterranean termite is extinguished in the long term”.
The expert explains that biocide bait systems have existed since 2000, they are the only ones that eliminate complete colonies, as well as being more beneficial to the environment and causing much less damage than other treatments developed in the world such as chemical barriers, which are still applied, for example, in the United States.
“We here, after the treatments to eliminate them, do a follow-up to see if the biocide can affect the plants, crops and other fauna that are in the soil. And this study has not been done anywhere else in the world”, he remarks.
The councilor of the Environment area of the Cabildo de Tenerife, Isabel García, endorses her words: “The treatments are going very well, we continue with the same protocol. First, a survey of the entire area is carried out, then the treatment is applied until control of the colonies is achieved, finally it is reinforced where there was no monitoring or where the territory still needed to be better examined.”
This month begins the winged phase, which will last until January of next year, a stage in which the insects appear on the surface and can be detected with the naked eye. And although a small rebound is expected, the situation can be said to be under control because people see it and are concerned, but they have the necessary information not to be alarmed.
The action that has been carried out so far covers some 600 hectares and five municipalities: Tacoronte, La Laguna, Santiago del Teide, Adeje and Arona. In the latter, the focus has been eliminated, as in Los Naranjeros, Garimba and Parque Atlántico, while in Santiago del Teide and El Pris the activity is in recession and in a short time it will also be possible to affirm that it is following the same path, assures García . The most active areas continue to be Valle de Guerra and the new focus detected a few weeks ago in Adeje, where 300 biocide baits have been installed in an area of approximately 15,000 square meters and some 1,000 control stakes will soon be placed to determine the perimeter .
There are currently 25,686 checkpoints in the territory. Of this amount, 8,723 are stations where biocide baits are placed, of which 791 have been consumed by termites, leaving the colonies completely eliminated.
disappearance time
Once the termite comes into contact with the bait it takes between 3 and 9 months to disappear, regardless of the number of colonies there are. To get an idea, a colony can reach up to 34,000 square meters, the equivalent of five football fields.
The weight that is put on each bait is 0.75 grams and as soon as the termite eats, “it is struck down with what is proven that the system and the biocide are effective,” says the counselor.
Likewise, 16,963 wooden stakes have been placed that have small grooves in the upper part, are buried to a certain depth in the ground, and allow detecting in which areas the insect is found, since having the nests in the ground makes them difficult to detect. see until there is very serious damage to homes, land or crops. In this way, the termites that go through galleries preferentially eat that wood, which is soft and allows it to be easily digested.
This eradication plan, which collects worldwide all the information that is known about the species and the peculiarities of the Canary Islands, the problems they can cause, the treatments and the actions to be carried out, was agreed upon by the members of the Technical Commission, made up of by the Cabildo de Tenerife, the Government of the Canary Islands and the municipalities affected. In addition, it has the participation of experts from the Institute of Natural Products and Agrobiology (IPNA-CSIC) and the University of La Laguna (ULL). In turn, the Cabildo, through the public company Tragsatec, monitors the implementation of the strategy and the improvement and proposal to update it.
The work of the Tragsatec researchers and staff has also evolved in these five years. Currently there are some teams, which through a georeferencing system, facilitate the detection of control points (stakes and stations with biocides) and the management of associated information, such as the dates on which each one must be reviewed without the need continuously manipulate them. Thus, there is a more computerized control of what happens inside the bait and makes work much easier.
Much progress has also been made in terms of information and citizen awareness. When the stakes were installed, there were neighbors who removed them and both the Cabildo and the municipalities requested the collaboration of the population to avoid this type of vandalism that did not help to combat the problem.
The same with the rubbish, fundamentally belongings, affected by the plague and thrown into the containers without any type of control. In the eradication strategy, a collection, transfer and elimination of remains of garden pruning and wooden equipment is carried out in a single point, a publicly owned plot located within the area affected by termites in the municipality of La Laguna.
Although the strategy is contemplated for a period of five years (it was prepared on December 4, 2020), this does not prevent further progress in research, tests and studies that help to extinguish the plague and reduce the costs it entails for the public administration the treatments.
At the moment, hexaflumuron is still being used, but tests are being carried out with diflubenzuron, the only two biocides approved by European regulations and continually exposed to EU reviews.
“We have received news that the first one could be withdrawn, but we do not know if it will finally be removed because so far we have not been officially warned or notified. However, when in doubt, we wanted to start doing tests to compare”, says García. They are carried out in an independent plot to see how it works and how effective it is. So far, one hundred baits have been installed since the station is larger, it weighs 300 grams and the grammage, therefore, is also different, 1.50 grams of diflubenzuron, which is also placed in powder form. You will have to wait at least a year for the results.
The investigations of the Higher Council for Scientific Research (CSIC) show that there is no proven toxicity after treatment with hexaflumuron in crops. “That gives us peace of mind that the weights we are using are eliminated in the process and do not harm health,” emphasizes the counselor.
But its cost is very expensive (150 euros each bait) and that is why it is not ruled out to try other formulas so that it can be declassified or its price rises and the administrations cannot afford it.
In the case of diflubenzuron, there are still no scientific studies by the CSIC.
Involvement of the municipalities
The budget invested so far to combat the plague amounts to 2.5 million euros. The largest investment has been made by the Cabildo. However, given the new focus that has appeared in Adeje, Isabel García considers that the municipalities should begin to include a specific item for termites in their accounts.
His attempts to get the Ministry for Ecological Transition to subsidize the eradication of this species, which has also been included in the Spanish Catalog of Invasive Alien Species through Order TED/1126/2020, of November 20, “have been sterile” , but “will continue to request it.”
Reasons are not lacking, if the objective, in addition to exterminating the plague, is that studies that are unique in the world continue to be carried out in Tenerife.
