Surely everyone has seen them before: Scaffolds made of wood, steel or concrete, with nets and films, stretching over fruit trees, berry bushes and strawberry fields. Many a walker or hiker may also have been disturbed by the constructions in the landscape. But one thing is certain: "For us fruit growers, such crop protection systems will secure our livelihood," says Ferdinand Völzgen, chairman of the Bonn/Rhine-Sieg District Fruit Growers Group. "Without roofs and hail protection nets, we can't produce the high-quality fruit that the trade and consumers demand from us."
Why are protective systems for fruit crops an indispensable part of modern fruit growing? One answer: freak weather - such as late frost in spring or heavy rain in summer - puts a strain on fruit crops throughout the year. What's more, globalization and climate change mean that more and more insect pests are threatening German fruit crops. One well-known example is the cherry vinegar fly, which originated in Asia and has spread rapidly through Europe in recent years. But so far it has no counterpart in our latitudes. It mainly attacks softer types of fruit shortly before harvest, for example cherries and berries.
Strawberries that grow in film tunnels are well protected from rain - and thus also from rot. Photo: Herbert Knuppen
What protection systems do fruit growers in the Rhineland use to protect the quality of their harvest? A few examples:
Hail nets: Many fruit growers pull nets over their apple trees after blossoming. They prevent hailstones from damaging trees and fruit. "Hailstones can make deep dents in apples, which can also lead to rot on the fruit if the weather remains damp," Gerd Moog, a fruit grower from Wachtberg-Fritzdorf explains. "So a single hailstorm can lead to the total loss of my apple crop. That's why I protect my fruit with hail protection nets."
Film tunnels and rain caps: In a rainy summer - as is the case this year - the persistent wetness ensures that a large part of the outdoor strawberries already rots in the field. So-called film tunnels and rain caps provide a remedy: The strawberries that grow under the films are well protected when it rains. "Before we put film over the tunnel arches in spring, we lay a thick layer of straw between the strawberry rows and the arches. When it rains, the water can slowly seep into it, even if the soil is dry," explains Friederike Schneider from Schneiders Obsthof in Wachtberg. "We also draw small ditches at the end of the tunnels with the plow. They allow the water to drain away in a controlled manner, even during heavy rains."
Sheltered cultivation has become indispensable in modern fruit growing. For example, many fruit growers cover their currant bushes with films to protect the fruit from rain - and thus from bursting. Photo: Herbert Knuppen
Film roofs: The films that fruit growers stretch over cherry trees or currant bushes, for example, preserve the quality of the fruit. Because without a protective roof, they would burst and rot in the rain. "Thanks to the roofs, my fruits remain firm and durable. This allows me to deliver them to retailers and end consumers," Manfred Felten, who runs a fruit farm in Meckenheim, explains. "Thus, protected cultivation systems also help to secure regional fruit production. Every kilogram of cherries we grow here, food retailers don't have to import from southern Europe or Turkey."
Nets: To protect cherries from the cherry vinegar fly, fruit growers in the Rhineland have only one effective means: they completely wrap their cherry orchards in a tightly meshed net. "The nets prevent the entry of these insects, which can otherwise cause immense damage to fruit that is ready for harvesting," says Felten. Like his colleagues, he only stretches the netting over the trees after flowering so that pollinator insects such as bumblebees and bees can pollinate the flowers.
Incidentally, in protected cultivation, fruit growers can largely reduce the use of pesticides. Thanks to tunnels, fruit growers can introduce beneficial insects into their strawberry crops, for example, which eat up insect pests. And in the case of his cherry trees, which are protected with a film roof and netting, Felten notes, "Netting is the smarter and most effective solution, better than spraying, for preventing pest infestation. Even though it involves cost and a lot of work - for me, there's no way around it."
In protected cultivation - as here in a film tunnel - fruit growers can reduce the use of pesticides and introduce beneficial insects. The colorful flowering strip next to the tunnels also provides a habitat for numerous insects. Photo: Herbert Knuppen
The Bonn/Rhein-Sieg fruit-growing specialist group is a regional sub-organization of the Provinzialverband Rheinischer Obst- und Gemüsebauer e.V., the professional interest group for fruit and vegetable growers in the North Rhine region of North Rhine-Westphalia. The professional group counts about 140 fruit growers from the southern Rhineland among its members. They grow not only apples and pears, but also other popular types of fruit themselves - for example strawberries, raspberries, currants and blackberries, sweet cherries and plums. The Rhineland fruit growers market their fruit from their own cultivation either through their own farm store or the trade - true to the motto: From the region, for the region.
For more information:
Fachgruppe Obstbau Bonn/Rhein-Sieg