A pest from the tropics gives a hard time to agriculture in Switzerland. The nightclub of the tomato (Helicoverpa Armigera) devours more than a hundred useful plants. The butterfly is now spreading north. In the south of Germany, his vanguard already causes damage.
Switzerland has been monitoring the propagation of the tomato (or armigage) since 2024 using 25 traps. In 2023, the caterpillar had already caused strong loss of performance in vegetable crops, going as far as total loss, explains the Federal Center for Agricultural Research (Agroscope), interviewed by Keystone-ATS.
At the end of June, the traps contained more butterflies than the previous year, observed Cornelia Sauer, expert in vegetable cultivation at Agroscope. The first damage of the season appeared on tomatoes south of the Alps.
In Germany, the caterpillars are already wreaking havoc on chickpeas, told the German press agency DPA Olaf Zimmermann, pests expert at the Augustenberg Agricultural Center (LTZ) in Karlsruhe. Some have already been found to Hanover and Berlin.
Worse than Japan’s beetle
“The nightclubs of the tomato are much more problematic in the great cultures than the scarab of Japan, for example,” explains Olaf Zimmermann. “The latter eats leaves and fruits and mainly goes to vine and fruits. The noctual of the tomato, however, goes in surface crops such as corn and vegetables on the spotlight ”. The insect is called night because it moves at night.
“There is not yet wintering in Germany, but arrivals each year,” says Olaf Zimmermann. “The question is not to know if he is going to come and stay, but when”. Butterflies can fly 1000 kilometers and cross the Alps. Cornelia Sauer considers that these tropical pests can spend the winter north of the Alps. At most, this would be possible in greenhouses.
According to experts, climate change moves the distribution zones to the north, as is the case for other pests. “We can assume that at one point, a population will adapt to our climatic conditions and that we may then have a first enclave in the south of the Land of Baden. In Hungary, they already hibernate, ”explains Olaf Zimmermann.
There, they established themselves permanently as corn pests. In 2023, butterflies attacked lavender in the south of France, causing significant loss of performance.
In Switzerland, national monitoring has highlighted the arrivals of butterflies from southern, west and east. The butterfly moves north, continues Cornelia Sauer, “he also reached the canton of Zurich”. The traps and controls in the field must make it possible to detect in time a presence in a region in order to save the crops by a targeted use of insecticides.
A missing monitoring in Germany
Surveillance would also be desirable in Germany, says Olaf Zimmermann: “But it unfortunately does not exist with us, because it is expensive and complicated. We often only act when the damage is already important ”.
“The reproductive potential poses a problem,” explains Olaf Zimmermann, “a butterfly female can lay more than 2000 ½ufs”. There are effective means of struggle, the important thing being timing: “The nightclub of the tomato is a drill. Once in the stem of a plant, we can no longer reach it. If we discover the first butterflies, we have two to three weeks to intervene. For this, monitoring would be important ”.
The caterpillars are polyphages, they appreciate a multitude of useful plants, beans with peas, tomatoes, peppers or sweet corn, passing by salads or beets. Even young caterpillars are not content to bite the leaves, they deeply dig into the plants. According to Agroscope, they are even more voracious at the subsequent stages of the caterpillar. In addition to these damage, vegetables are soiled by droppings, which makes the harvest unusable.