Therepopillia japonica, as well as almost all non-native species, it is invasive and harmful to our territory. An alien species, also called alien species, is that which in biology is described as a species that, due to human activities, finds itself colonizing a territory other than its natural habitat.
When a allochthonous species fits into a new environment three scenarios can occur; in the best of cases (and also the rarest) the species integrates perfectly into the new habitat. In the second case, the species is unable to adapt and therefore becomes extinct, or, as happens in many cases, the alien species manages to adapt and survive in the new habitat, reproducing even in large numbers, altering the balance of the new environment. The allochthonous species can compete with one or more native species: the native species have natural predators while the alien species, having settled "artificially", may not have any natural predator and therefore take over the other species.
In Europe it is estimated that over 13,000 alien species have been introduced with a considerable economic and environmental impact: 1300 species of these are the cause of negative impacts on the environment andpopillia japonicais among them.
In addition topopillia japonica, other negative examples concern the red weevil and the nutria, both introduced accidentally with human activities.
Popillia japonica in Italy
Therepopillia japonicait is a recently introduced beetle of Japanese origin: the first damage to local crops dates back only to 2014. The first outbreaks of the infestation concern the region Lombardy, in particular the area of the Ticino Park and near the Turbigo (Milan). In the summer of 2014 also the Piedmont has seen several reports, especially in the area between Pombia and Galliate.
Reporting of the Popillia Japonica
If you have spotted a specimen of Popillia japonica you are required to report it to the Phytosanitary Services of your region. Popillia japonica usually "comes out" in the late afternoon, it does not like to feed in full sun so during the hottest hours of the day it stays in the shade of plants and leaves.
How to recognize Popillia Japonica
Popillia japonica is represented in the photo above. Unfortunately, this beetle originally from Japan can be confused with insects typical of our countryside, which are not harmful. To distinguish and recognize Popillia japonica, you can observe the sides and the distal area (last segment) of the abdomen where the alien species has five spots of white hair on each side and, in fact, in the terminal area of the abdomen.
Fight against popillia japonica
The fight against popillia japonica makes use of three different strategies:
- manual capture of the beetle
- capturing adult insects by pheromone traps
- biological struggle introducing the natural predators of popillia japonica in every moment of the life cycle (adult, larva or pupa)
There biological struggle it was found to be very effective in the United States. In particular, in North America, the wasp was exploitedTiphia vernaliswhich would seem easy to adapt even in our territory. The small wasp (only 10 mm long) has Asian origins and exploits the larvae of the popillia japonica asnestfor the laying of its eggs.
Another antagonist is the already knownBacillus Thuringiensis, a bacterium that can already be purchased in formulations. I have already talked about it in the past because it is the same bacterium used in the biological fight against the box borer. Even with the fight by means of Bacillus Thuringiensis it goes to attack the popillia japonica in the larval stage of its biological cycle. To start thebiological struggleagainst thepopillia japonicait is possible to buy on Amazon the hydrodispersible granules that allow the bacterium Bacillus Thuringiensis to penetrate the soil and eliminate the larvae ofpapillia japonica. All information on price and methods of use are available on the Amazon page: Biological control with Bacillus thuringiensis granules.
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