What is a Pest?
A "pest" doesn't necessarily mean an insect. A pest is anything that interferes with the growth and development of the crops in your garden, and can be anything from a roly poly to a groundhog to a deer.
I'm sure you've heard of how today's "big farmers" walk around in hazmat suits because of how dangerous the herbicides and pesticides that they spray on the crops they raise are, or have seen that one compensation commercial about that common weed killer causing cancer and other crazy health issues. If you haven't heard of these, get from underneath that rock!!
During the two years that I worked on an organic farm, we implemented a series of methods to protect our crops from pests as opposed to just spraying everything with dangerous and environmentally damaging chemicals. This series of methods is known as Integrative Pest Management, or IPM for short. Gardening pests and IPM are rabbit holes in themselves, so I'll keep it as simple as possible on this post so it doesn't seem as intimidating.
Common Garden Pests
The type of pests you encounter in your garden will vary depending on what crops you're growing and your location. For example, your crops may face more deer intervention if you live near woods or a forest preserve as opposed to someone in a city environment or on open prairie land. I've compiled a list of some of the most common pests (based on what I've personally experienced as a farmer, this list is not exhaustive) and what crops they tend to stick to:
Larger Animals (deer, groundhogs): Leafy greens like kale, collard greens, mustard greens, salad mixes, spinach, etc.
Aphids and Ants: When you see ants, 9/10 that means there are aphids. Aphids don't seem to have a type and will attack just about anything. I've witnessed aphids on leafy greens like kale as well as on fruiting plants like okra.
Roly Poly/Pill Bugs and Slugs: Roly polys (also called pill bugs) and slugs tend to attack crops that are overly moist. Ensuring good air flow can prevent them. I've seen both attack leafy greens like bok choy and collard greens.
Flea Beetles: Flea beetles can be a PROBLEM if left unaddressed. You'll know you have them if you begin to see tiny holes in your crops. They look like little black dots and often fly away if you move the plant in a rapid manner. Flea beetles are a big fan of eggplants, leafy greens like kale, collard greens, salad greens, mustards, and even the leafy green tops of root crops like turnips and radishes.
Tomato Hornworms: Hornworms are one of the few critters that give me the heebie jeebies. They look like green caterpillars and vary in size, but the damage they cause to tomatoes almost can't be ignored. You'll find them on tomatoes (obviously) and possibly on bell pepper plants. I've attached a photo I took myself of a tomato hornworm at the farm this past growing season.
Cucumber Beetles: Cucumber beetles tend to be a yellowish-gold in color with small black dots. They actually resemble ladybugs, except they aren't our friends. Cucumber beetles stick to plants in the cucumber family like cucumbers (obviously) and zucchini/summer squash.
How to Manage these Pests?
Again, this list is not exhaustive, as this is beginner friendly.
Large Animals (deer, groundhogs): Covering your crops is the best way to protect them from larger pests like deer and groundhogs. Agribon is a breathable white sheet that you can prop up over your plants to cover them. Ensure that the Agribon doesn't contain any openings or holes and is securely pinned to the ground/soil pot that your plants are growing in. It should NOT be leaning on the plant. Invest in wire hoops or makeshift structures to keep the agribon suspended. Although it is breathable, it is important to peel back the agribon regularly to allow your plants to receive unfiltered airflow and sunlight. Our bok choy on the farm this past season was attacked by roly polys because the agribon was left on too consistently and caused too much moisture. Roly polys and slugs love moisture.
Deer fencing is also an option for those with larger landscapes. Its basically a removable fence that keep the deer from accessing your garden altogether. Other types of "cages" would work for smaller crops grown in pots or containers. As long as your plants can breathe and get sunlight, cover them with what you can.
Groundhogs don't like the smell of castor oil. You can sprinkle castor oil pellets either around your crops or wherever the groundhog is hiding, but of course that means you'd have to locate it first which isn't always the easiest thing to do. Castor oil pellets should be at your local home improvement store. If not, they can always be found somewhere online.
Aphids and Ants: Aphids can easily be washed off of your plants with a spray of pressurized water. You can also make insecticidal soap, which is basically dish detergent and water mixed together and applied to your plants via spray bottle. The fats in the dish detergent break down the outer layers of the bug's cell membrane, exposing their insides to air and essentially causing them to dry out. I like to use Dr. Bronner's unscented castile soap instead of dish detergent to keep things truly natural, but either one works.
Roly Polys/Pill Bugs and Slugs: As addressed earlier, roly polys and slugs won't be an issue in your garden as long as every crop has ample air flow. Diatomaceous Earth (DE) also works well for bugs with this type of physical structure. DE is made from the shredded fossils of other animals that are no longer alive. It's essentially powdered bone. The particles are so small that it doesn't bother the skin of humans, but is detrimental to the outer membrane of smaller bugs like beetles. It is essentially death by 1,000 cuts: the DE cuts up the outer shell of the bugs and exposes their insides to air, causing them to dry out. Sounds harsh, but in order for one thing to be created or grow, something else must be destroyed. Natural order. And managing it this way protects the environment, as DE will just decompose and rejoin the cycle. It is recommended to wear a mask when applying: although the particles are too small to affect human skin, they may irritate the more sensitive lungs if inhaled.
Flea Beetles: There are a number of ways to organically address flea beetles, but the most beginner friendly way would be using thyme oil. You can mix thyme oil alone with water in a spray bottle or add it to your insecticidal soap spray. Pure thyme essential oil works, but you also should be able to find some in the gardening section of your local home improvement store. When in doubt, look for some online. BE SURE TO DILUTE IT. Thyme oil alone is too strong to apply directly to plants and can damage them if not diluted. Treat your plants how you'd treat a person; people shouldn't apply undiluted essential oils to their skin either!
Tomato Hornworms: Similar to flea beetles, there are a number of ways to address hornworms, but the most beginner friendly way would be to wash them off or pick them off by hand. Of course, this would require you to locate them all, which can be hard because they camouflage SUPER WELL, but is very effective. Once they have been removed from the plants, take them to an area far away from your plants and dump them outside. Let them become a natural part of the food cycle vs killing it yourself please.
Cucumber Beetles: Insecticidal soap with neem oil works well to combat cucumber beetles. Neem oil works as an organic pesticide for just about anything in the garden. DE would also work here.
Beneficial Insects
Not all insects are bad! Some insects actually help to protect your crops from pest attacks, as these insects don't eat your crops, but rather eat the insects that are eating your crops. A few common examples of beneficial insects include spiders and ladybugs.
If you see a lot of ladybugs in your garden, you more than likely have aphids, as that is their food of choice. Whenever you see a huge gang of beneficial insects like ladybugs or spiders in one place, you should be looking for what they're eating, as that is what is attacking your garden.
When to Do IPM Sprays?
IPM sprays should be done either really early in the day (by 10AM latest) or late in the evening once the sun has begun setting. You NEVER want to do IPM sprays dead in the middle of the day when the sun is super hot and high in the sky, as it can cause the substances you are spraying on your plants to "burn" or "fry". Think about what would happen if you applied heat to any oil...same concept. Spraying earlier or later in the day when the sun isn't at His highest allows for the sprays to dry on the plant BEFORE the sun really starts beaming to avoid any type of scorching.
DIY Insecticidal Neem Spray
1/4 tsp Castile Soap (or dish detergent)
1/4 tsp pure neem oil
Add both to a spray bottle and fill the rest with water. Shake well and apply to applicable plants. Aim for the leaves, not the flowers, to protect the bees!