Madagascar's fight against new locust plagues
It is common practice to treat large insect infestations with appropriate insecticides. In the case of the migratory locusts, too, this was the reason why for a long time the Universal insecticide DDT was resorted to. In this way, the prevalence of the voracious insects was successfully contained. Today, the use of insecticides is viewed rather critically: not only does the use of a broad-spectrum insecticide reduce the sensitive ecosystems endangered for a long time to come, they also accumulate to a considerable extent in the Food chain on and have thus uncontrollable long-term effects.
Nowadays, science has finer and more effective weapons to fight grasshoppers. By carefully studying the insects' way of life, it can be exploited and used as a weapon against rampant spread. The behavior of grasshoppers is hormone-driven. It was discovered that the animals, which actually live singly, only come together in swarms when they release an appropriate hormone. The hormone is released when the locusts strike their hind legs together. If this hormone is present in large quantities, the insects cluster in swarms of up to one billion animals together. Most recently, the great migratory locust plague of 2013/14 affected Madagascar's Agriculture led into a deep crisis. Instead of the harmful broad-spectrum insecticides, grasshoppers are nowadays beaten with their own weapons: Thus, they are Hormones used, which not only Prevent swarming behavior, but even the Inhibit larvae formation. However, the use of this agent, which is harmless to the ecosystem and thus also to humans, is very expensive. Madagascar would need additional funds of several million euros a year to use hormones to combat the rampant locusts.
Cheaper alternatives for the control of grasshoppers
There are other approaches to controlling grasshoppers sustainably, but only some of them have been tested in practice. Here, too, one benefits from a precise knowledge of the insects' way of life. All locust species have in common that they invade because they rely on Foraging are or because they are settle after long flight from exhaustionto feed later. This need of the pests to rest and to rest one makes oneself in some beginnings grasshoppers to fight to use. Already in the past, animals that have not yet reached the flight stage, were swept up or collected. If the infestation is too large, such action is hardly possible. In order to stop even large swarms, installations are now being tested in Uganda that provide the animals with a Offer resting place, at which they are then informed about a Slide to be transported to a collection basin. To provide an additional incentive for the animals to settle, the machines can be fitted with Fragrances that attract the insects. Large plagues of grasshoppers could thus be tackled at low cost. The plants can be reused and are not a burden on sensitive ecosystems. Only the scents have to be procured anew in the event of a large infestation. Let us hope that these cost-effective and sustainable method nip large plagues of locusts in the bud soon became widely established.
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Villa Sibylle Antananarivo (Madagascar)
