Many scientists fear the imminent arrival of the Japanese beetle in France. And if these pests are of such concern to authorities, it is because they devour our plants and destroy crops. Christine Tayeh, from the agency national food, environmental and occupational health safety (Anses) is coordinator of the Expertise Cell Biological Risks Plant Health† She gives us valuable advice to prevent it.
Why does the Japanese beetle arrive in France?
The arrival of the Japanese beetle (or Popillia japonica) is due to many factors, and especially to its natural flight distribution from neighboring countries where the insect is already present (e.g. Switzerland and Italy), as well as to its long-distance movement. In addition, all the conditions are met for this pest to develop on our territory: presence of host plants (maple, rosebush, vine, fruit trees, etc.) and favorable environmental conditions (temperature, precipitation and soil moisture).
How to protect against the Japanese beetle?
If you observe the presence of one or more Japanese beetles, immediately notify the regional services of the Ministry of Agriculture. This report is essential in order to be able to take the appropriate measures, especially because: “the Japanese beetle is a priority quarantine organism”in other words, an animal species that is classified as a pest according to the list drawn up by the European Commission.
Christine Tayet explains to POSITIVR that preventing the establishment of the Japanese beetle requires a series of measures that: “are not sufficient when each is considered individually.” To ensure their effectiveness, they must be placed quickly and early at the start of the invasion.
It’s an eco-friendly method of dealing naturally with pests that destroy our crops, transmit disease, or infect our plants (as is the case here). The idea? Eliminate unwanted with biological pesticides† Among these natural enemies we have the fly istocheta aldrichi, including the eggs, as shown in the image below. Indeed, when they become larvae, they enter the beetle and feed from the inside.
To complicate the survival of the larvae and thus the damage of these pests on the plants, it is advisable to apply cultural control. It is a natural and sustainable method that aims to adapt planting and tillage practices.
In particular, Christine Tayet advises: reduce irrigation during the critical spawning period (ie between mid-May and mid-August). In addition, it is recommended to to the ground in the fall because the larvae burrow deep into the ground (about 35 centimeters) to avoid the winter frosts. Turning the soil multiplies the chances of eliminating these pests.
Control through massive trapping
This other measure is a good alternative to chemical control. As the name suggests, this technique involves: use traps to collect pests to severely restrict their growth in an infested area. These can be pheromone, food bait, chromatic or luminescent traps. In the case of the Japanese beetle, this solution only works “facing weak isolated populations”explains Christine Tayet.
The scientist also insists on one point: to reduce the risk of developing the Japanese beetle, it is imperative to combine these three measuresnamely biological control, cultural control and mass capture control, and to add chemical control with the use of active substances approved against adults and larvae. Of course, the use of these phytosanitary products must be incidental in order to respect the environment and promote biodiversity.
Note that if the Japanese beetle is a destructive insect, its cousin, the ground beetle, is a valuable ally to the gardener. In addition, here are 8 insects that are urgently welcome in your garden to pollinate your plants, fertilize your soil and control pests.