It is only two inches long and, at first sight, a little visible butterfly. But the corn borer, which has spread more and more in southern Germany since 2006, is a source of annoyance for farmers. Or rather, its larvae. "The larvae dig into the stem and then migrate down, which can damage it, making the corn plant unstable and overturns," says Kristin Schwabe of the State Institute. for agriculture and horticulture of Bernburg. Can also penetrate through holes in larval fungi, which further damage corn.
To avoid this, pesticides can be used. When European crows hatch from their nymphs from May to July, they can not mate and lay new eggs. The National Institute of Agriculture and Horticulture is currently testing a different, more environmentally-friendly method, in a field located near Neugattersleben. It buzzes what are called Trichogramma parasitic wasps.
Parasitic wastes instead of pesticides
Like ladybugs or brigands, they belong to the natural enemies of corn borer. Only they are rare in the wild. The larvae of parasitic wasps are only 0.4 millimeters wide. Nearly 2,000 pieces are in a single compostable cellulose bullet that is dropped by the drone.
"This trichogramma parasitic wasp crawls, looking for maize borer eggs and parasites." And so, the wasps do not grow anymore, but the wasps, "says Axel Weckschmied, who offers as one of the few in Germany, this type of biological pest control.
The parasitic wasps themselves are harmless in his words. If they can no longer find food – then there is no more corn borer eggs – they die.
A test for the future
For the test in Neugattersleben, Kristin Schwabe of the state institute for agriculture and horticulture has divided the cornfield into three plots. One of them will be treated twice, once and not at all during the test period. "We would like to take a look: is it worth it to be used once or do you have to fly twice here?" We also look at the profitability, the efficiency of the project. Trichogramma application and we want to show farmers: There are alternatives to the chemical protection of plants, "says Kristin Schwabe, For a reasoned statement, however, the test should last at least three years.
Farmer Jörg Frisch, who owns the cornfield, is already interested in this. The fall of wasp from the air does not only seem exciting, it also has advantages: "For economic reasons, it makes no sense to go with a tractor and make a Zünslerbekämpfung.J & # 39; The second aspect is a bit ecologic: because the future brings us a modified crop protection situation and you have to exercise a little bit. "
Not a panacea
With wasps but alone, corn borer can not fight. Because it's growing in Saxony-Anhalt, has different reasons. According to Schwabe, the ever warmer climate ensures optimum development conditions for the larvae. On the other hand, the area under maize has almost doubled in the last ten years. "And another problem is that some farmers who have been fattening for many years and whose lower hygiene measures, such as a reduced cut cut and good stubble fragmentation , do not conform systematically, "explains Kristin Schwabe.
This takes time and entails additional costs. In order to avoid significant long-term damage to maize, it is necessary to combine different measures. The National Institute of Agriculture and Horticulture, with its trichogram test, also wishes to advertise.
About the author
Marie-Kristin Landes was born and raised in Dessau-Roßlau. After graduating, she moved to Dresden to study politics, then to Leipzig for the Master's Degree in Journalism. She has gained practical experience at the Good medical, at the ZDF-Auslandsstudio Wien and as a freelancer on detektor.fm online radio. After her internship at Mitteldeutscher Rundfunk, she now works mainly for MDR Kultur and Landesfunkhaus Sachsen-Anhalt. When she is not traveling for the MDR, she prefers to be on the outside. She can not choose between sea or mountain, but also between dog and cat.