Natural enemies, especially a combination of generalists and specialists, can be an extremely useful part of pest management programs that recognize and encourage their activity.
Natural populations of insect pests are commonly attacked by pathogens, and some pathogens have been mass-produced to use as biocontrol agents (e.g., microbial insecticides). Insect pests are susceptible to entomopathogenic nematodes (roundworms) and a variety of diseases caused by pathogens, which include viruses, bacteria, fungi, and protozoa. In some cases, the benefits of natural enemy presence are often undervalued because they are difficult to sample or even detect. Natural enemies can be disrupted by chemicals, can struggle in poor habitat with low pest numbers, and may be incapable of suppressing pests below damage thresholds by themselves. Specialist natural enemies, such as most parasitoid wasps, have more restricted food choices so will leave or die out when prey numbers are low. When target pest numbers are low, generalist natural enemies may maintain populations locally by consuming other prey species. Generalist natural enemies, such as most aphid predators, can switch readily among alternative food sources. Ideally, natural enemies reproduce on their own and are self-sustaining, they are not harmful to other aspects of the ecosystem, and they can be used in combination with other integrated control tactics. A reduction in natural enemies can also produce dependence on further pesticide usage and result in a cycle of chemical dependency that has been called a “pesticide treadmill”. The term “secondary pest outbreak” is used when this scenario occurs. Biocontrol agents tend to be highly susceptible to non-selective pesticides, so even short or moderate pesticide exposure times may reduce their populations and allow minor pest insects that would otherwise be held in check to become major pest problems. We use the terms “natural enemies,” “beneficials,” and “biocontrol agents” synonymously to refer to predators, parasites (or parasitoids), and diseases of pests.īiocontrol is generally more compatible with organic and sustainable agricultural approaches than pesticide-dependent agriculture, especially when non-selective, broad-spectrum chemistries are used. The degree of pest decline might be in the form of partial or complete pest suppression. We define biological control as the decline in pest density as a result of the presence of natural enemies. Biological control (or biocontrol) is a key component in establishing an ecological and integrated approach to pest management.
0 kommentar(er)
