They often measure no more than a millimetre in length, but they are absolutely invaluable. Natural enemies such as predatory mites and parasitic wasps engage in battle on a daily basis with common infestations in horticultural businesses. We call this ‘biological crop protection.’
More than 90% of the vegetable cultivation in the Netherlands involves the use of biological crop protection. Dutch-grown vegetables are therefore seen as some of the cleanest in the world. Natural enemies are also used more and more frequently in the cultivation of flowers and plants.
Aphids: they infest houseplants and garden plants and reproduce extremely quickly. In no time at all, a once proud and strong plant looks very sorry for itself. Aphids also represent a threat to horticultural crops. Many chemicals become ineffective in the longer term as the pests develop resistance. The frequent use of such chemicals is also not good for growth or productivity. Growers may choose to release parasitic wasps, for instance. A parasitic wasp pierces the aphid and lays an egg inside it. This results in the aphid’s death, and the wasp is able to reproduce successfully.
Predatory mites used to combat spider mite, for instance, are supplied in scatter bottles or other containers. If the grower detects excessive numbers of spider mite in the crop, he or she scatters the predatory mites onto the leaves of the plant near the pests. The predatory mites seek out the spider mites, catch them, and then suck out their insides. These predatory mites are so tiny that they are barely visible to the naked eye.
Click to watch an animated film showing two examples of biological crop protection.