Integrated Pest Management – IPM / Biopest

Integrated Pest Management – IPM

An attentive reader of pest management literature may notice that the term “Integrated Pest Management”, or IPM, is often used interchangeably with the term “Integrated Pest Control”, or IPC. They are indeed very similar to one another. However, while IPC refers to various methods of controlling pests, including the integration of natural methods with chemical pesticides, IPM also considers ecological and economic factors, including prioritising the careful monitoring of insect populations and the surrounding environment. With IPM it may be that no pest control is necessary, or that a certain kind of pest control is better than another, or that the best option is several used together, in order to achieve the best result for your economy, society, and environment. Many methods of IPM are therefore promoted by FAO to achieve different objectives in different countries, each offering concrete ways farmers can combat pests in ways to promote healthy crop production, fiscal returns, and overall safety. 

IPM Principles (by FAO)

1. Growing Healthy Crops

Choosing varieties that naturally resist diseases and pests, as well as fertilizer, irrigation, and soil management that will best aid plant development, are vital principles of IPM. Growing strong plants—those that will best resist disease and insect damage—is the foundation of IPM.

2. Understanding and Sustaining Natural Predators

There are many natural predators of pests that are friends of sustainable agriculture. It is necessary for the farmer to observe insect life to both understand pest populations and recognise the role of natural predators in a farm’s lifecycle and food chain. Effective biopest control will incorporate these natural enemies of pests: predators, parasites (or parasitoids), and pathogens.

2.1 Predators are animals or insects that prey on other animals or insects, typically those that are smaller than them, in large numbers, and at every stage of the prey’s lifecycle (egg, immaturity, chrysalis, maturity). Typical predators of pests include birds, frogs, toads, lizards, snakes, spiders, dragon flies, ladybugs, orange ladybugs, ground beetles, green lacewings, stink bugs, and praying mantises. Predators can be categorized into two groups:

            1. Biting predators (eg ladybugs, orange ladybugs, ground beetles).

            2. Sucking predators (eg stink bugs).

2.2. Parasites, or parasitoids, are small organisms that survive on other organisms, known as the host, in the process weakening or killing that organism. A parasite can enter and develop inside a host in all stages of its development (egg, immaturity, chrysalis, maturity), and can live its entire life in a single host. Female parasites harm their hosts by laying eggs inside them, for example Trichogramma and Anastatus. 

2.3 Pathogens are microorganisms that live and prosper on animals or insects, causing disease, or, ultimately, death. Disease-causing pathogens include viruses, bacteria, fungi, nematodes, and protozoa. Various pathogens will naturally attack pest insects, making them vital elements of integrated pest control.

2.3.1. Viral Biopesticide: Utilising viruses in pest control is beginning to attract widespread attention. One efficient example of such a virus is the Nuclear Polyhedrosis Virus, or NPV, a viral biopesticide that can specifically target certain pests- for example, the beet armyworm NPV will only harm beet armyworms; the cotton bollworm NPV will only target cotton bollworms. Other beneficial insects will not be harmed. NPV can multiply rapidly in its host, killing them quickly, but can also spread easily, including transmission by butterfly.

Symptoms: When caterpillars contract NPV they will start moving more slowly, eat less, their bodies will begin to change colour, and they will attempt to climb to the highest tips of plants. There they will sit calmly, stop eating altogether, and die, hanging suspended by their heads. The wall of their stomach will then break open and NPV’s crystallized protein particles, which contain the virus, will be released, dispersed by wind and water. Pests therefore propagate their own virus. 

2.3.2. Bacterial Biopesticide (Bactericide): Bacteria are microorganisms that live in plants and soil and can be both harmful and beneficial. The most commonly used bacteria for biopesticide are of the Bacillus species, for example Bacillus Thuringiensis (Bt). Bt can target specific pests, such as beet armyworms, cabbage loopers, diamondback moth, white caterpillars, and cotton bollworms, while leaving natural and beneficial predators unaffected. Bacillus subtilis (Bs), meanwhile, can control diseases caused by fungus and bacteria, and is proven to be safe for humans, animals, plants, and the environment. Such bacteria must be consumed first by the insect, whereupon it can enter their stomach and cell-walls, releasing poison that will slow its digestive system, cause the insect to become swollen and, finally, burst open and die.

2.3.3. Fungal Pesticide: Many varieties of fungi are utilised around the world to combat pests and plant diseases. In Thailand the most commonly used are Trichoderma and Beuveria. Trichoderma is used to control root rot and wilt caused by other fungi. Beuveria is used against rice thrips, moina, white flies, aphids, and brown planthoppers, among others.

2.3.4. Nematodes: Nematodes are small organisms that live in the soil and water. Some can cause certain diseases, for example the nematode Meloidogyne spp. causes root-knot diseases in tomatoes, betel, and other vegetables. Other nematodes, however, known as “free-living” nematodes, do not cause disease. These can be separated into two groups, both of which can be used in biopest control: Steinernema and Heterorhabditis. The most commonly used variety is Steinernema carpocapsae, which can harm many kinds of insects by excreting a poisonous bacteria inside them, causing them to die in 24-48 hours.

2.4. Natural Herbicides:         Many plants in Thailand can be utilised in biopest control, and have already been used in certain areas for a long time. Neem, galangal, turmeric, Siam weed, lemon grass, non taai yaak, derris, and others can be used as repellents and to disrupt the eating habits and development of pest insects.  Among these plants the most beneficial is Neem. Extracts from neem are currently widely used in Thailand and around the world for pest control.

Methods of Conserving and Protecting Natural Predators

1. Protect and conserve the plants that serve as food for these natural predators in farms, rice fields, and gardens. These include plants of the genus Jussiaea, species of balsam plants, pickerel weed, globe amaranth, goat weed, morning glory, and various grasses. These are plants that do not have real economic value, but their pollen and nectar provide food for beneficial natural predators throughout the year, helping sustain healthy populations.
2. Create environmental conditions that will support natural predators. One way to do this is employing crop rotation, which will both help natural predators survive each season while controlling the new influx of pests in the next growing season.
3. Increase moisture with watering, or provide sufficient water to beds during dry seasons. This will also help natural predators survive and propagate.
4. Don’t burn rice residue after harvest, as this will upset the equilibrium of a farm’s ecosystem. It is one reason pests spread quickly at the beginning of certain seasons: natural predators have been killed.
5. Observe both your natural predators and pests closely and consistently. Don’t use chemicals in areas with high natural predator populations and low pest populations, for example.

The Benefits of Taking Care of Natural Pests

1. By taking measures to support natural predators, agriculturalists are utilising a natural resource that already exists in their farms, rice fields, and gardens, to practice long-term, efficient pest control.   
2. Helping to maintain a balanced ecosystem will decrease both established pest numbers and the arrival of new pests.
3. Biopest control makes plants safer to eat, so it benefits consumers.
4. Biopest control rewards farmers in many ways—economically, socially, and environmentally—by decreasing the amount of chemical pesticides that need to be imported and reducing the obstacles facing exporting to foreign markets.

3. Survey Your Plots Regularly

It is important to monitor and evaluate the development of your plants, including the presence of diseases, weeds, and pests. Plots should be surveyed weekly for pest damage and other factors affecting the ecosystem, including natural predators, soil, water, and air quality, and anything else that will affect your plants.

4. Farmers as Experts

An essential element of modern agriculture is the farmer taking responsibility for the management of her own production and income. This means gaining an understanding of how various elements are related and bringing that understanding to the management of a farm. This will help a farmer make independently, increasing both the efficiency and potential scope of management. Becoming the expert on a farm therefore means learning new skills and gaining a correct understanding of agricultural ecosystems.

Biopest Control Methods

Biopest control methods range from the extremely simple, which farmers can practice daily by themselves, given the right training, to the more difficult, requiring specialised training. Agricultural scientists and professional farmers already understand that some of these methods have mild effects, while the effects of others are strong. This is why they must be used together, or integrated. The ultimate aim is to find the combination that works most efficiently, saves most resources, is most safe for the farmer and consumer, and kindest to the environment.

Methods of Biopest Control

1. Appropriate Plant Management

This means maintaining appropriate environmental conditions to help plants develop, grow strong, and resist pests.

1.1 Improving soil. This means preparing beds with the appropriate pH level for plant development, mineral content, and surface consistency, without aiding the development of pests.

1.2 Use good plant varieties. Quality plant varieties are better at resisting pest. Help them by using the appropriate planting ratios, spacings, and seasons.

1.3 Water and fertilizer. Apply regularly, using the right quantities and formulas.

1.4 Tillage. Certain pests are killed when the soil is turned and they are exposed to sunlight. 

1.5 Weeding. Many weeds are home to pests and secondary hosts to plant diseases. Weeds also consume the food of plants, making them weak. 

1.6 Pruning. When branches are too long foliage grows too dense, preventing plants from synthesising enough sunlight and increasing moisture. This creates a more desirable home for pests.

1.7 Crop rotation. Crops planted should alternate season by season, or planting should alternate between plants from different families. This will interrupt the food source of various pests.

1.8 Crop integration. If a single crop is planted across a wide area and pests arise, they will spread rapidly across the entire population. Integrate crops to limit pest food sources and opportunities for them to spread.

1.9 Postpone planting. It is sometimes useful to postpone the planting of certain annual plants, or those with short lifespans, to avoid times when diseases are rampant. For example, in Thailand cassava is normally planted at the end of the rainy season, from October to January. The cassava plant then hits drought in March-April, coinciding with the hot weather perfect for the spread of  the cassava mealybug. It’s therefore recommended cassava is planted at the beginning of the rainy season instead, about mid-April, so that it doesn’t go without water and maintains strength. The rainy season then provides inhospitable conditions for the cassava mealybug. Another example is the current spread of the brown planthopper in Thailand on rice farms where rice is planted year-round. This provides a source of food for the brown planthopper that never goes away. It’s therefore recommended that rice isn’t planted more than twice a year in order to disrupt the brown planthopper’s lifecycle.

2. Mechanical Control

This is the use of machines or other tools to lower pest populations. If numbers are low enough, human labor can be sufficient.

2.1 By Hand. The simplest form of pest control: pick pests off plants, or hold the plant and shake them out, and exterminate.

2.2 Human Labor. Pruning diseased plant matter, or those parts covered with established pests, and burning it to exterminate pests. 

2.3 Netting. Netting can be used to isolate plants from outside pests entirely.

2.4 Traps. Insects and other animal pests, such as mice, birds and bats, can be exterminated in traps.

2.5 Motor-run Machines. Some motor-run machines can be used for pest control, for example a grass hopper-catching machine and an insect-sucking machine.

3. Using Physics for Pest Control

This is the use of methods and scientific instruments to lure, repel, and exterminate pest populations through the use of heat, sound, and light.  

3.1 Radiation. Radiation can be used to exterminate a pest population from a crop before exporting, for example irradiating fruit before exporting it to America to kill durian seed borers, mango seed weevils, and the oriental fruit flies Bactrocera dorsalis and B. correcta. Or radiating herbs to kill fungi, etc.  

3.2 Sound. A hand-held machine that produces sound waves at a low frequency can be used to drive certain pests from an area.

3.3 Heat. Baking soil is one way heat can be used to exterminate pests. Hot steam can also be used to exterminate pests clinging to crops.

3.4 Traps. This method must target specific insects. For example, light can be used to target those insects that like to fly around at night (place a container of water beneath a light bulb). Vacuums can also be used to suck insects, a method popularly used with moths and brown planthoppers. Methyl eugenol-baited traps, meanwhile, are effectives ways trap male fruit flies, while protein-baited traps can lure oriental fruit flies of both sexes.

4. Using Natural Predators to Control Pests

4.1 Kinds of Natural Predators: As noted above, predators (such as dragonflies, spiders, (), etc), parasites (such as various parasitic wasps, nematodes, etc), and pathogens (such as bacteria, fungi, viruses, etc) can all be used to control pest populations.

            4.2 Advantages

1. 1. Low-cost, as the natural predators already live in agricultural ecosystems, will work without pay, and will lower other pest-control inputs on the farm.
   2. Sustainable in the long term, as natural predators will sustain their own populations if they have enough food and are not harmed by chemical pesticides.
   3. Natural predators do not cause pests to develop disease resistance, or give rise to new varieties of pests.
   4. Natural predators do not harm forms of life other than pests, and do not poison the environment. They will also not harm crops, as they do not eat crops for food.
   5. Natural predators do not harm farmers, consumers, or the environment.

5. The Sterile Insect Technique (SIT)

The FAO has identified SIT as an effective method of biopest control that doesn’t harm the environment.  Once released the sterile insects will procreate with ordinary insects, creating eggs that do not hatch. This will decrease the overall insect population. If enough sterile insects are released, three generations will see significant decreases in the pest population. Several pests have been successfully controlled in Thailand with this method: various kinds of fruit fly, Diamondback moths, and cotton bollworms.

6. Natural Extracts as Pesticides

Various extracts taken from natural sources have potential to control pests, such as neem seed extract, lemongrass, betel, derris, Non Taai Yaak, etc.

7. Chemical Control

Careful use of chemicals is acceptable in an integrated pest management system. However, they must be seen as a final measure only necessary when other methods have been tried without success. (Much more.)

A Comparison of Chemical Pest and Biopest Control Methods

Resources:

ECHOcommunity. https://www.echocommunity.org/en/resources/ce2006be-0f4c-4405-8dd9-2fdb6e4ea250. Accessed 26 July 2022

FAO. https://www.fao.org/pest-and-pesticide-management/ipm/integrated-pest-management/en/. Accessed 26 July 2022.