Biological control agents are biological organisms that feed on the pests they target. Some are generalists, while others specialize in a particular species. For example, predatory mites Amblysieus swirskii feed on whiteflies, thrips, and broad mites. Phytoseiulus persimilis, on the other hand, feeds exclusively on spider mites. Some biological control agents are used against one particular pest, such as caterpillars. Bacillus thuringiensis subsp. kurstaki, meanwhile, is effective against caterpillars.
Biocontrol agents are released in the field to establish insectaries
Insectaries are managed by releasing natural enemies into the field. These agents are beneficial in a variety of ways. Their release in the field replaces the use of pesticides, while their presence in the field increases human safety. Exposure to large quantities of insect bodies causes allergic reactions in humans. For this reason, air exchange and filtration are used in insectaries to reduce skin contact with arthropod body fragments. Insectaries may also contain non-native natural enemies that pose risks to native species. Specifically, non-native species can become established outdoors in areas with permissive climates. They can compete with native insect species, and may even outcompete them.
Many biocontrol agents are native species, which can serve as natural predators. Many of these species are also specialized. Successful introductions of these organisms have mapped out their life histories and other attributes. This information is essential in planning a successful release. Insectaries will help in natural colonization, and conservation efforts can further improve the outcome. However, it is important to remember that not all biocontrol agents can control all pests.
Biological control programs must be designed to consider non-target effects. This includes identifying the species of pest and its native environment, identifying the natural enemy, raising the natural enemy, and evaluating the biocontrol agent’s efficacy in the field. Biological control agents must meet the guidelines of the North American Plant Protection Organization (NAPPO). The NAPPO requires that researchers provide data on non-target impacts.
While there are many benefits to biological control, the most common barrier to its widespread application in western agriculture has been socio-economics. In western agricultural systems, economic efficiency and the economy of scale are priorities. In addition, the application of agrichemicals has created entire support industries. Therefore, biological control products must possess similar characteristics to pesticides, including residual activity and ease of use. They must also be easy to apply, a prerequisite for broader adoption.
In addition to releasing natural enemies in the field, agronomists must also develop effective monitoring systems and methods to evaluate the effectiveness of their results. The primary objective of augmentative biocontrol is to synchronize the life cycles of a pest and its natural enemy. This method is also short-term, as the biocontrol agents released will disperse quickly if the agroecosystem does not provide suitable habitats.
They affect the vegetative parts of the plant
Biological controls work by introducing a plant’s natural enemies into its environment, removing its competitive advantage. These agents, which are called biocontrol agents, attack specific organs and parts of a plant, such as the fruit or the seed. The main difference between biological and chemical control is the target of biological control. While chemical treatments may target pests that attack a specific part of a plant, biological controls target the entire plant.
Biological controls can have a variety of effects, affecting the entire plant, from reducing the number of insects to damaging useful parts of the plant. Some agents can also be used to reduce the reproductive potential of plants, limiting dispersal and follow-up work after clearing a forest. Biological controls are typically used in plant-based systems that target invasive species. The use of biocontrol agents on trees is not recommended if the plants grow for wood or seeds. This can damage seed orchards.
They suppress and maintain populations of a target pest species
Biological controls are methods that use natural enemies of a target pest to suppress and maintain their population. These creatures are carefully chosen and released in areas where the target pest is abundant. Their release can cause minimum disturbance to the surrounding environment. Many of these techniques are also eco-friendly, minimizing the need for harmful chemicals. Biological controls can be used in combination with other methods to control pest populations, such as weed killers, fungicides, and microbial sprays.
Biological controls include many types of biological pest control methods. The key components include natural enemies of pest species such as parasitoids, predators, and pathogens. Conservation of natural enemies, mass rearing of predators, and periodic releases of pathogens are examples of natural controls. Abiotic factors also affect the population of a target pest species. In addition to natural enemies, biological control can also be used in agronomic crops, as pest weeds are often resistant to many of these methods.
Some pests require pollen or nectar to survive. However, crop plants only flower uniformly for a short period, thereby limiting their ability to provide pollen or nectar to predators. In these cases, the presence of supplemental sources of pollen and nectar can stabilize populations of generalist predators. Biological controls also depend on their ability to respond quickly to an outbreak of a target pest species.
Insects can be infected with pathogens that cause disease and reduce their growth or reproduction. In addition, some nematode species have bacterial symbionts and can infect insects. These natural enemies can be used in preventative measures when targeted pests are not available for control. These natural enemies have a diverse range of prey species. They also play an important role in maintaining pest-free ecosystems.
They are replaced or supplemented by chemical or other control measures
A biological control refers to the deliberate use of natural enemies of target pest species to suppress their populations. Bio-based pest management is one of many methods of controlling pests that are replacing or supplementing chemical or other control measures. Bio-based pest management aims to create safer, more effective ways to combat pests while minimizing the use of chemical or synthetic pesticides.
The main disadvantage of chemical control methods is that they disrupt natural systems and kill beneficial species. Therefore, it is important to replace chemical applications with biological control measures if possible. However, many farmers still do not adopt these methods, primarily due to socio-economic issues. Moreover, the use of pesticides in large-scale agriculture has developed an entire industry that revolves around the application of agrichemicals.
Biological control methods may also hurt the ecosystem. Insecticides can kill off natural enemies or make the habitat unsuitable for their reproduction. Furthermore, agricultural practices such as repeated tillage may kill off small predators and parasites, thereby increasing the population of insect pests. Consequently, periodic washing of citrus foliage can enhance the biological control of the California red scale by up to 99%.
Biological control methods are often a part of integrated pest management (IPM) programs. It is often complemented by chemical or other control measures. Bio-based pest management techniques may include microbial pesticides, behavior-modifying chemicals, and genetic manipulation of pests and host plants. Bio-based pest management strategies are often based on knowledge of past interactions, including the effects of native insects and beneficial insects on crops.
Biological control methods are not entirely effective, and sometimes a combination of chemical and biological approaches will be necessary. The most common biocontrol agents used are the convergent lady beetle and predatory lacewings. Several other biocontrol agents are being investigated for sustainable cockroach control. It is crucial to effectively communicate the benefits of IPM to farmers, as this will increase their chances of successfully adopting IPM.
(For more pest control blog, check this article: What is the best way to get rid of bees?)