Insects
Insects fulfil an indispensable function for agriculture with their pollination work. Their countless species include numerous beneficial insects which protect crops against pests. Insects thus take on a role in natural crop protection.
The pollination work of insects
In their search for food, insects fly to flowers to gather pollen and nectar. As they crawl around a flower, pollen sticks to them. In their continuing search for food, they then transport this pollen to the next flower and pollinate it. Most plants in the world couldn’t exist without this type of pollination. And insects are by far the biggest contributors. While bees are the best-known pollinators, a range of fly and mosquito species, and also butterflies and beetles, assist plants with their pollination. In Switzerland, the pollination work performed by insects is valued at up to half a billion francs each year.
Bees
Honeybees live in large colonies, while wild bees are solitary creatures. What both have in common is their importance for agriculture.
Flowering strips – agriculture promotes insects
Swiss farming families are fully aware of the value of insects. This is why they make sure to offer them habitats. One way they do this is by sowing flowering strips or strips for beneficial insects. When the fruit trees and rapeseed blossom in the spring, a lavish spread awaits the insects. Once blossoming is over, however, the supply of pollen and nectar drops significantly. The insects can then find food on the flowering strips in the fields. The beneficial insect strips are designed even more specifically for beneficial insects – in some cases even offering them a habitat in winter too.
Predatory mites
Deploying beneficial insects against pests constitutes a biological form of pest control. The strawberry mite is scarcely visible to the naked eye. Infestation is frequently only discovered when the heart leaves curl and go brown. Damage can occur particularly in perennial crops and greenhouses. Predatory mites can be deployed in large numbers to control pests or to supplement plant protection agents. They are hung between the strawberries on small cardboard sheets.
Ichneumon wasps
Strawberries can be infested by many different aphid species, including potato, cucumber and peach aphids. Farmers deploy ichneumon wasps against these pests as a preventive measure. Ichneumon wasps can be released regularly in small cardboard cylinders. The wasps are highly host-specific. In other words, they specialise in a single type of aphid. Since several species of aphid are generally found at one and the same time, these beneficial insects are generally employed in mixtures.
The predatory gall midge can be deployed through repeated applications. When the first aphids appear, large quantities of ichneumon wasps or green lacewing larvae must be brought in immediately to control the pests. Green lacewing larvae are particularly suitable for treating outbreaks of colony-forming aphids. Ichneumon wasps, by contrast, display good foraging behaviour and track down individual aphids. A combination of these beneficial insects thus constitutes the optimum solution.
Insects as pests
Not all insects are useful for agriculture, however. Some of them have a devastating impact on the harvest. One well-known example is the spotted wing drosophila introduced from Asia, which causes major damage to fruit and vines. Also, the caterpillars of the corn borer, a small butterfly, constitute one of the greatest threats to corn cultivation. In Switzerland, the corn borer is frequently controlled with ichneumon wasps, brought out onto the fields by drones in some cases.
This might also interest you
Bees
Honeybees live in large colonies, while wild bees are solitary creatures. What both have in common is their importance for agriculture.
Plant protection
Swiss farmers protect their plants with preventive measures. Nevertheless, they still have to resort to plant protection products to safeguard yields.
