As every year, the treatment against the moth caterpillar takes place in the various gardens and parks of Toulouse. From 6 am, the product is dispersed on the boxwoods to prevent them from being devoured by these insects which feed exclusively on these shrubs. Explanations.
Fabien Boffelli is one of the gardeners fighting against the spread of this species of caterpillar. This year is a little different from the previous ones for him. “Usually, it is more in March or April that the treatment should be done.” This phenomenon is due to episodes of heat which favor the laying of eggs, explains Philippe Golfetto, deputy to the head of the maintenance and guarding service of green spaces. “Since last week, our teams have been working on several sites to stop the spread of the borer, which quickly attacks boxwood,” he says.
The problem with these caterpillar attacks also lies in the impact on boxwoods which, after being eaten, can die. The challenge of this treatment therefore remains to protect the plant from its gradual disappearance. “It is a local and hardy species that grows spontaneously, but the world of plants is constantly evolving. Plant diversification is important and the boxwood may need to be replaced in the years to come, ”says the deputy head of the department.
Biological insecticide
Now there is the problem of the dangerousness of the products used and their impact on the ecosystem. The main control of its insects is Bacillus thuringiensis kurstaki (BTK), a biological insecticide. “The BTK is placed on the branches and the caterpillar, by eating them, will become poisoned”, clarifies Philippe Golfetto while admitting that certain species of insects can also suffer from it.
That the residents be reassured: “The substance used is identified as biological and is authorized within the framework of the biological struggles” he recalls. A period of closure of the parks of six hours is planned for the time of the release of the product to avoid inhalation, but I understand everyone’s fear ”he concludes.
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