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Natural Pest Control: Safe Methods That Work


Written by: Yicheng Sun

Reviewed by: Rebecca Newbold


Intro: In this article we talked about natural pest control methods that are safe and efficient. The chemical pesticides kill good bugs and bad bugs, and leave harmful chemicals around your kids and pets. Instead, biopesticides and biocontrol can control pests naturally with minimum toxic side effects!


Controlling pests naturally with minimum toxic side effects
Controlling pests naturally with minimum toxic side effects

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An alternative solution

Biopesticides

Biocontrol 



An alternative solution 

As gardeners, it is safe to say that we share the joy of watching our gardens and vegetable patches come to fruition. Although as a plant enthusiast myself, sometimes those joyful moments were stolen from me because of pests or diseases. Pesticides target pest insects and their larvae, but would also hurt many beneficial insects in the process. In the previous article, we discussed the negative impacts of pesticides on bees. The presence of chemical pesticides in home gardens can also post potential threats to house pets and children. For planters that value the idea of environmental health, biodiversity, and a safer method of pest control than chemical pesticides, biopesticides and bio control would be great solutions to your problems. 




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Biopesticides: Natural Pesticides

Biopesticides are certain types of pesticides derived from such natural materials as animals, plants, bacteria, and certain minerals. There are three major classes of biopesticides: 

  1. Biochemical pesticides: naturally occurring substances that control pests by non-toxic mechanisms. Biochemical pesticides include substances that interfere with mating, such as insect sex pheromones, as well as various scented plant extracts that attract insect pests to traps. 

  2. Microbial pesticides: a microorganism (e.g., a bacterium, fungus, virus or protozoan) as the active ingredient. Microbial pesticides can control many different kinds of pests, although each separate active ingredient is relatively specific for its target pest(s). For example, there are fungi that control certain weeds and other fungi that kill specific insects. The most widely used microbial pesticides are subspecies and strains of Bacillus thuringiensis, or Bt, which can be used to specifically kill one or a few related species of insect larvae.

  3. Plant-Incorporated-Protectants (PIPs): pesticidal substances that plants produce from genetic material that has been added to the plant. For example, scientists can take the gene for the pesticidal gene and introduce the gene into the plant's own genetic material. Then the plant manufactures the substance that destroys the pest. (EPA, 2024)

One of the most common biochemical pesticides used at home is neem ((Azadirachta indica) oil. An oil pressed from the fruits and seeds of this tree contains insecticidal and fungicidal compounds, as well as azadirachtin, which acts as a growth disruptor for more than 200 species of insects. (Trinklein, 2015) 


As for microbial pesticides, microorganisms or microbes (fungi, bacteria and viruses) and plant extracts can reduce pest populations by killing, repelling, excluding them, or by hampering their growth or reproduction. For example, products that contain the bacterium Bacillus subtilis (BT) can help control powdery mildew. BT bacteria work by producing compounds that do the pest-fighting work for them. The fungus Beauvaria bassiana can kill insect pests outright, while some strains of BT bacteria will stop an insect pest from feeding. (Cornell CALS) 




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Biocontrol: Reducing Pest Populations

Biocontrol is the method of reducing pest populations using living organisms or the things they produce. Biocontrol methods would include natural enemies and biocontrol agents. There are three main types of biocontrol: 

  1. Conservation biocontrol: Support natural enemies that are already present by providing them with food, shelter, and protection from things that harm them (for example, pesticides). Natural enemies occur in all production systems, from the backyard garden to the commercial field. They are adapted to the local environment and to the target pest, and their conservation is generally simple and cost-effective. 

  2. Classical biocontrol: Release a natural enemy (once or only a few times) that will reproduce and keep pest populations in check. When a natural enemy is successfully established it rarely requires additional input and it continues to kill the pest with no direct help from humans and at no cost. Classical biological control is long lasting and inexpensive for growers and gardeners. 

  3. Augmentative biocontrol: Release or apply natural enemies repeatedly (whenever needed) to reduce pest populations. Natural enemies may be released at a critical time of the season (inoculative release) or literally millions may be released (inundative release). The cropping system may be modified to favor or augment the natural enemies if it supports natural enemies that are already present in the environment. (Cornell CALS)


It is easy to observe natural enemies of the pests, such as lacewings, lady beetles, hover fly larvae, and parasitized aphid mummies present in aphid colonies orfungus-infected adult flies following periods of high humidity. Many adult parasitoids and predators benefit from sources of nectar and the protection provided by refuges such as hedgerows, cover crops, and weedy borders. By altering the cropping system, it can enhance the effectiveness of natural enemies on the pests. Examples of alterations include growing flowering plants (pollen and nectar sources) near crops to attract and maintain populations of natural enemies. Work in California has demonstrated that planting prune trees in grape vineyards provides an improved overwintering habitat or refuge for a key grape pest parasitoid. The prune trees harbor an alternate host for the parasitoid, which could previously overwinter only at great distances from most vineyards.


Note from the CEO: In our garden, we dealt with large aphid populations. To handle these, we introduced lacewings & parasitic wasps into our garden. Aphids rapidly declined and this year we have seen significantly fewer!




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Enemy introduction is another important factor for biocontrol. The practice of importing and releasing natural enemies to control pests is the essence of classical biocontrol. One of the earliest examples of successful classical biological control programs was with the cottony cushion scale (Icerya purchasi), a pest that was devastating the California citrus industry in the late 1800s. A predatory insect, the vedalia beetle (Novius cardinalis), and a parasitoid fly were introduced from Australia. Within a few years the cottony cushion scale was completely controlled by these introduced natural enemies. 



Unfortunately, classical biological control does not always work. It is usually most effective against introduced pests and less so against native insect pests. Hence, repeated release of natural enemies is usually applied. Periodic releases of the parasitoid, Encarsia formosa, are used to control greenhouse whitefly (Trialeurodes vaporariorum), and the predaceous mite, Phytoseiulus persimilis, is used for control of the two-spotted spider mite (Tetranychus urticae). Lady beetles, lacewings, or parasitoid wasps are frequently released in large numbers. Similarly, entomopathogenic nematodes are released for control of certain soil-dwelling insect pests. (Cornell CALS)



By choosing biopesticides and biocontrol over synthetic chemicals, we can protect beneficial insects, safeguard wildlife habitats, and keep children and pets safe from toxic residues. These nature-based strategies work with the garden’s natural rhythms so your soil health improves, your plants bloom brighter, and pest outbreaks become less of a surprise. Embracing these methods transforms pest management from a battle into a balanced partnership with nature, ensuring that your garden remains a thriving, vibrant sanctuary for years to come.




Sources:

Environmental Protection Agency. (2024, October). EPA. https://www.epa.gov/ingredients-used-pesticide-products/what-are-biopesticides

Trinklein, D. (2015, June). Biopesticides: Eco-friendly pest control . Biopesticides: Eco-Friendly Pest Control // Missouri Environment and Garden News Article // Integrated Pest Management, University of Missouri. https://ipm.missouri.edu/meg/2015/6/Biopesticides-Eco-Friendly-Pest-Control/


 
 
 

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