Pest control involves using methods to prevent or reduce the occurrence of undesirable organisms. These may include physical barriers, traps and netting. Click Here to learn more.
Biological pest control leverages natural predators and parasites to manage unwanted organisms. The bacterium Bacillus thuringiensis, for example, is used to control caterpillars and grubs. Other biological control agents are mosquito-eating fish and nematodes that prey on rootworms.
Preventive pest control methods are used to keep a pest population below an acceptable level without causing harm to other organisms or the environment. They may involve structural, cultural, or chemical measures.
Effective structural prevention focuses on reducing places where pests can enter, hide, or breed. It includes frequent and thorough cleaning, properly disposing of garbage, and keeping plants and grasses trimmed away from the structure. Sealing cracks and crevices with caulk or steel wool is also helpful, as is fitting windows, doors, and vents with screens. Other simple steps include storing foods in plastic containers or glass, keeping trash tightly sealed, and using dehumidifiers in crawl spaces and basements.
Monitoring consists of regularly searching for, identifying, and assessing numbers of pests and the damage they are causing. This can be done by scouting (searching for and observing) or sampling (collecting samples). It also involves collecting data such as pest counts, damage to vegetation or structures, and feeding habits. The information collected can help identify a problem, determine its severity, and determine how often it should be controlled.
The goal of scouting and monitoring is to detect pests and their damage before they reach damaging levels. This is sometimes known as threshold-based decision making. For example, a single wasp flying around outside the house occasionally does not require action; however, seeing them in increasing numbers daily or finding their papery nests warrants immediate action.
Culture-based pest controls include the use of bacteria, viruses, fungi, and other microorganisms to disrupt or kill pests or their eggs. These methods typically have a low environmental impact and are often safer than chemical pesticides, which can be harmful to humans and pets.
Cultural methods include keeping living areas clean, storing food in sealed containers, and removing food waste. It is also important to maintain adequate moisture levels and to control waste water runoff. These measures help prevent the growth of pests that are attracted to rotting garbage, moist soil, and damp wood materials. In addition, it is helpful to know what type of pest you are dealing with so that a specific preventive measure can be applied.
Suppression
Natural enemies (predators, parasitoids, disease organisms and competitors) can reduce pest numbers. Their effectiveness depends on the situation, landscape context, and interactions among species that may be additive, synergistic or antagonistic.
Several different species of birds, reptiles, amphibians and fish feed on some insect pests. Predatory arthropods such as ants, beetles and ground beetles also suppress pest populations.
Some pests are attacked by bacteria, fungi and protozoans that infect them, slow their growth, prevent reproduction or even kill them. Some plants are attacked by pathogens that damage them or make them less vigorous or tolerant of environmental stressors, such as drought or flooding.
Weather conditions often affect pest activity and population levels, particularly temperature, day length and humidity. Pests are more active or reproduce faster when weather conditions are favorable to them.
The use of resistant varieties, plant or crop protection products, methods to manipulate pest mating or host-finding behavior and the application of certain pheromones can control or eliminate pests. The need for pesticides can be reduced by using these or other cultural practices, and coordinating pesticide applications with other suppression tactics.
Pesticides can have detrimental effects on natural enemies and other environmental resources, so it is important to minimize their use. Pesticides are often less effective than expected because of the tendency of pests to develop resistance, which can occur either naturally or through repeated exposure to a given substance.
Farmers should closely monitor the appearance of pests after taking precautionary measures to prevent them. This process, called monitoring or scouting, allows the farmer to identify the problem and assess its severity. It is essential that the scouting or monitoring effort is accurate and consistent so that it can provide useful information about future prevention and avoidance activities. In addition, monitoring provides the opportunity to determine whether suppression tactics are working or not and, if not, what changes might be needed. The monitoring process also helps the scout or monitor understand why the pest problem occurred in order to prevent it from recurring. A good monitoring program includes follow-up assessments to evaluate the effectiveness of pesticides and other control tactics.
Eradication
Eradication is the ultimate goal of pest control. It is a massive undertaking that requires an understanding of ecology and biology along with a huge amount of community support, funding, staff and volunteers. Jenny says, “In eradicating pests such as stoats and rats it is essential that all predators are eliminated along with the weeds that provide food for them.”
The process involves mapping a landscape to establish what is and isn’t a problem and what habitats may or may not support the pest species. Using this information, home owners can determine the threshold at which damage is unacceptable and take corrective action before reaching that point. This often requires monitoring, recording pest counts and making estimates of when the population will reach damaging levels.
It also involves accurate identification of the pest, its life cycle, and factors such as weather that influence its development and numbers. This will allow the use of management tactics that are less harmful to the environment, the landscape and the ecosystem as a whole.
In the example of a weed, this might involve mowing regularly to keep it down or mulching around plants to prevent germination and deprive weeds of sunlight that they need for growth. It could also involve removing the weed before it becomes too large or applying herbicides to kill it.
In some cases, the use of biological controls such as parasites or pathogens can be used to reduce the number of pests. Biological control is more effective than chemical controls and relies on the interaction between a host plant or animal and its natural enemies. A pest’s enemies can include parasitoids, such as lacewing insects and lady beetle larvae, predators such as ground beetles, and disease organisms like nematodes and mycoplasmas. It can also include methods that alter the insect’s genetics or behavior, such as releasing large numbers of sterile males or chemicals such as juvenile hormones.
Monitoring
Monitoring is an essential part of a proactive IPM program, providing information on pest populations that can help determine when control tactics are needed. The goal is to detect pests before they reach threshold levels that lead to unacceptable damage or injury and allow the proper control measures to be taken before serious problems develop. Monitoring is done through random plant inspections and use of sticky traps, pheromone or volatile bait stations, and indicator plants.
Monitoring also helps provide data to support the decision to treat an area or specific field or building. This information will include the pest identification, the location and severity of damage, and the rate of development. It is vital that a trained employee conduct the monitor to ensure the accuracy of the data collected.
The most common method of detecting pests is by visual observation. This is often used for aphids, mites and certain psyllids, but is less effective for mirids and other insects. An extendable mirror can be useful for allowing an inspector to inspect under equipment and in other secluded areas where pests hide. It is also helpful to have a magnifier, which can aid in the detection of insect parts, frass (excrement) and other evidence of pest activity.
A regular schedule of monitoring is important to determine the best timing for treatments. It can be difficult to predict when a pest population will reach a damaging level and it is important that the correct action is taken at just the right time. Monitoring can also give clues on what is causing a pest problem such as nutrient deficiencies, disease or other environmental stresses.
It is also critical to know the legal requirements of your operation and understand how they may impact your control strategies. In many areas, it is illegal to have certain pests in your produce or facility. Therefore, a legal control strategy is necessary in these situations.
A good IPM program will be based on prevention and suppression, with eradication as a last resort. However, there are some pests that cannot be tolerated in enclosed environments and so eradication is sometimes a viable option.