Biological pest control in the context of "Organic farming"

Biosecurity refers to measures aimed at preventing the introduction or spread of harmful organisms (e.g. viruses, bacteria, plants, animals etc.) intentionally or unintentionally outside their native range or within new environments. In agriculture, these measures are aimed at protecting food crops and livestock from pests, invasive species, and other organisms not conducive to the welfare of the human population. The term includes biological threats to people, including those from pandemic diseases and bioterrorism. The definition has sometimes been broadened to embrace other concepts, and it is used for different purposes in different contexts.

The COVID-19 pandemic is a recent example of a threat for which biosecurity measures have been needed in all countries of the world.

Pest control is the regulation or management of a species defined as a pest; such as any animal, plant or fungus that impacts adversely on human activities or environment. The human response depends on the importance of the damage done and will range from tolerance, through deterrence and management, to attempts to completely eradicate the pest. Pest control measures may be performed as part of an integrated pest management strategy.

In agriculture, pests are kept at bay by mechanical, cultural, chemical and biological means. Ploughing and cultivation of the soil before sowing mitigate the pest burden, and crop rotation helps to reduce the build-up of a certain pest species. Concern about environment means limiting the use of pesticides in favour of other methods. This can be achieved by monitoring the crop, only applying pesticides when necessary, and by growing varieties and crops which are resistant to pests. Where possible, biological means are used, encouraging the natural enemies of the pests and introducing suitable predators or parasites.

In evolutionary ecology, a parasitoid is an organism that lives in close association with its host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionary strategies within parasitism, distinguished by the fatal prognosis for the host, which makes the strategy close to predation.

Among parasitoids, strategies range from living inside the host (endoparasitism), allowing it to continue growing before emerging as an adult, to paralysing the host and living outside it (ectoparasitism). Hosts can include other parasitoids, resulting in hyperparasitism; in the case of oak galls, up to five levels of parasitism are possible. Some parasitoids influence their host's behaviour in ways that favour the propagation of the parasitoid.

Dendroctonus micans, the great spruce bark beetle, is a species of bark beetle native to the coniferous forests of Europe and Asia. The beetles attack economically important spruce species including Picea abies (Norway spruce) and Picea sitchensis (Sitka spruce). The adults burrow into the bark of the trees and lay eggs there. The larvae feed on the phloem under the bark; they can girdle the tree if present in large enough numbers.

The species is a serious pest of commercial forestry, and is an invasive species in many regions where it is not native, such as the United Kingdom, France, Turkey, Georgia, and North America. While its main host is spruce, it also attacks coniferous trees of other genera, including firs such as Abies sibirica (Siberian fir); pines such as Pinus sylvestris (Scots pine); the Douglas-fir Pseudotsuga menziesii, and the common larch, Larix decidua. Biological pest control has been applied using a natural predator, the beetle Rhizophagus grandis, in several countries.