Biological pest control

Biological pest control is defined as the deliberate introduction of viruses or animals by humans to decimate the population of certain ( " harmful " ) animals or plants. This is usually resorted to organisms that are known as natural enemies (predators, parasites and pathogens ) of the undesirable kind. It is also possible to change individuals so that they harm the population of their own species. In addition, organisms can be used, which are threatening by their droppings for unwanted species.

The so often equated use of products that are based only on the reduction of the use of pesticides or insecticides is misleading and is more likely with the term Biological plant protection in combination.

Biological control is not limited to agriculture but is used from time immemorial in the stock business.

Principle of biological pest control

Biological control makes use of the fact that in a balanced ecosystem normally occur no pests in the sense of excessive multiplication as a negative feedback of predator- prey numbers stabilizes the overall system (see predator-prey relationship - but is also under natural conditions known mass occurrence of species see locusts, lemmings ). A claim of biological pest control is therefore maintaining a minimum biodiversity. The colonization of beneficial insects is supported, and / or they are grown and exposed in the affected area.

Successful examples

Since 10000-3000 age cats are bred to abide by Mouse Hunt storerooms largely of small mammals free.

A classic example of biological control is the installation of nesting boxes for the settlement of insectivorous birds or perches for birds of prey to the decimation of rodents ( farming ) or songbirds ( fruit growing ).

A more modern example is the control of soil-dwelling insect larvae, like those of striated vine weevil ( Otiorhynchus sulcatus ) or the garden chafer ( Phyllopertha horticola ), with entomopathogenic nematodes Heterorhabditis bacteriophora of the genus. The yielded nematodes infect the pest larvae, which brought along a bacterium ( Xenorhabdus ) kills them or processed for nematodes as food. Nematodes are considered safe for plants and show no effect on warm-blooded animals. Their effect on non-target organisms ( non -targets ) is due to insufficient investigation but still controversial. Another important genus Steinernema would.

In organic farming, especially in organic viticulture, also ladybugs and their larvae against aphids are used. The problem here is that this world of the Asian lady beetle ( Harmonia axyridis ) was used, which now threatens to displace native species in Europe and North America.

Also, certain parasitic wasps (eg the genus Trichogramma ) can selectively bred and unwanted insects are used against some of the people. Their field of application is not in agriculture but in the storage industry.

Another example of biological control, in this case by phytonutrients that biofumigation that in some plants contained isothiocyanate (mustard oil) is exploited makes to reduce land-based pathogens.

Strategies of biological control are applied to the meadows in the field of aerodromes to avoid flocks of birds often.

Hazards

Biological control with ignorance can inflict immense ecological and economic damage. The colonization of the Australian continent, but also in many other regions, may take testimony (eg, rabbit and fox plague in Australia). A well-known example is the introduction of the cane toad in Australia, originally intended to control a sugar cane pest, developed, even a nuisance.

Ecologically harmful biological control is always, if not for the habitat and typical of the region and foreign organisms from the people there are ( mass ) is introduced.