Organic Pest Control

Caitlin Youngquist
Jul 4
3 min read

The plants in your garden are part of a larger ecosystem and provide essential food and habitat for all sorts of critters! Sometimes our attempts to grow more food can be stymied by too many plant-eating insects. When this happens, there are few tools we can use to our advantage.

First, identify what is eating your plants! This is very important if you want to avoid using synthetic pesticides in your garden. You can get some help with identification from University of Wyoming Extension or you local Weed and Pest Office. Do not rely on AI powered apps alone.

Once you identify the pest and learn about their life cycle and vulnerabilities, you can choose the right tools and practices.

The goal is not to eliminate all pests, but rather to keep them at a tolerable level.

There are three ways we can manage unwanted critters in the garden:

Cultural Control
1. Boost plant nutrition and health to make them less attractive to pests
2. Reduce pest habitat around plants
3. Alter planting time / density of vulnerable plants
4. Create a diversion - physical barriers and trap crops
5. Physical removal of insects - traps, by hand, or with water
Biological Control
1. Natural enemies - nematodes, bacteria, predatory insects, etc.
2. Poultry
Chemical Control
1. Systemic insecticides - absorbed by the plant, kills the insect when they eat the plant
2. Contact insecticides - kills insects on contact with poison, smothering, damaging exoskeleton, etc.
3. Repellents - deters pests

We often start with the last category (chemical) when we really should be starting at the top of the list (cultural).

Start with healthy plants by boosting plant nutrition and building healthy soil. Here are a few tools that might help:

Foliar feed with fish emulsion, liquid kelp, liquid humates, and chelated iron.
Use compost extract or protozoa tea to support diverse microbes in the soil that help provide plant available nutrients.

Create physical barriers to protect sensitive crops using nets, or floating row covers. There are many pests that can be trapped, but you must first know what you are trying to trap and what they are attracted to.

Before you start spraying things all over your garden, consider the effect on pollinators. Here is a good chart on pollinator safety for organic pesticides.

If you must resort to chemical deterrents and poisons (organic or synthetic), here are some less toxic options:

Spinosad - Contact insecticide made from a soil bacterium that kills beetles , spider mites, thrips, caterpillars, etc. Will harm bees when wet.
Bacillus Thuringiensis - Bacteria that provides systemic control of cabbage looper, tent caterpillar, tomato hornworm, beetles, etc.
Diatomaceous Earth – Contact insecticide that kills insects with an exoskeleton including fleas, earwigs, pill bugs, etc. Works great around flower pots, and in heavily mulched areas that provide habitat for earwigs and pill bugs.
Garlic Oil - Acts as a deterrent for insects and birds (including mosquitos!)
Neem Oil - Acts as both a deterrent and a contact pesticide, as well as suffocating some insects.
Horticultural Oils - suffocates some insects, and prevent some fungal diseases; can be plant or petroleum based, and sometimes include insecticidal compounds.
Grasshopper Bait - must be eaten by the grasshoppers; contain an attractant and the synthetic pesticide carbaryl or a grasshopper pathogen.