This article is a guide to organic pest control. North American households use around 135 million pounds of synthetic pesticides every year, amounting for 75% of total usage (farmers account for the other 25%). The use of these pesticides leads to the contamination of soil and water, and is causing health issues in children and adults. Organic gardening (gardening without the use of pesticides or other synthetic chemicals) is better for your health and the health of the planet.
With organic gardening, though, we need to find more creative ways to deal with pests. This article will cover the various methods of pest control, and then cover what methods to use with specific pests.
SOME GENERAL GUIDELINES FOR HAVING A HEALTHY, ORGANIC GARDEN
First, here are some general ideas to help you grow a healthier garden.
Prevention is key- the best way to avoid pest damage is to stop the pests from coming in the first place. The best way to do this is by having a strong, healthy garden. How to achieve this:
1) Have a strong, healthy soil. This will lead to stronger plants that are more resistant to pests. To do this, incorporate the use of composted material to supply the proper nutrients and encourage the presence of helpful organisms. To learn more, read composting 101 and the benefits of composting and how to lay a mulch for your garden.
2) Encourage a variety of plants and insects in your garden. This will invite helpful insects (which we will learn about later), and will help create a balance that makes being overrun with pests less likely.
3) Encourage the presence of wild birds, or even chickens and ducks, which will feed on potential pests.
4) Water early in the day, to keep plants dry as often as possible. Being too wet will encourage insects and fungi. A drip irrigation system will help to bring water to the roots while keeping the leaves of your plants dry.
5) Remove any weak plants. They will encourage infestation, if they aren’t infested already.
6) Plant more than you need, to give you a buffer. If you’re left with too much at the end of the year, you can always give it away or use it some other way.
7) Crop rotation. Incorporating this will make it harder for a pest infestation to really take hold.
METHODS OF ORGANIC PEST PREVENTION
Here are some of the most effective and popular methods of pest control used in organic gardening.
Floating Row Covers
These are made of a polyester fabric that you can drape over metal loops, or even just lie on top of your plants, to serve as an insect barrier. They let in 80% of the sunlight that hits them, but can lead to higher temperatures of the area they cover, so use the thin fabric in the summer and the thicker fabric to extend the growing season (ie use in the early spring or late winter).
Row covers are usually used as a temporary measure, for when plants are seedlings or when pests are most prevalent. If a plant needs insect pollination, row covers must be used sparingly.
Bacillus thuringiensis (BT)
This is a bacterium naturally found in the soil, that when consumed releases a protein that kills an insect. There are different forms of BT that target specific kinds of insects.
It usually comes in a spray or dust that you apply as soon as you spot the larvae of the insects (you must get them before they mature). Wear a mask and goggles when applying, and apply in the evening or when it is overcast.
A vegetable oil from India that is effective as a natural pesticide.
Contains animal fats that dissolve the skins of insects. Only effective in liquid form, so apply in the early morning and rinse after a few hours.
These will suffocate pests if it hits them. Dormant oils kill eggs and spores during the dormant season. Use lighter oils on plants during growing season to minimize damage.
Again, avoid spraying on a hot day.
These attract insects by releasing pheromones. They aren’t greatly effective, but can serve as a warning sign to start incorporating more effective and invasive methods.
These are made with a sticky material that traps pests, and come in colors that attract them.
Yellow attracts fruit flies, whiteflies, winged aphids, leaf hoppers and fungus gnats.
White attracts whiteflies, cucumber beetles, and flea beetles.
Red spheres attract the flies that lay apple maggots.
Light blue attracts flower thrips.
Parasites that release bacteria and kill host insects. You can buy them dormant, and mix with water when ready to use. Apply to the soil and then water them in.
Garlic Pepper Spray
Blending garlic and hot peppers together, removing the pulp and diluting the result with water will leave you with this spray. It is effective against some pests.
SPECIFIC PESTS AND THE BEST WAYS TO DEAL WITH THEM
Here is a listing of common pests, and the most effective ways of dealing with them.
Spray with diluted soapy water and then rinse with clean water a few hours later
Prune affected areas
Plant flowers and herbs that encourage ladybeetles and hoverflies, which will feed on aphids (more on this below).
BT and spinosad are very effective
Encouraging paper wasps (install a bottomless birdhouse near your garden for them to nest)
Bt is effective
Adding canola or olive oil to the tips of the corn ears when the silk begins to show
Colorado Potato Beetles
Having chicken or ducks
Yellow sticky traps
Using rigid collars (plastic cups or toilet paper rolls used to create a wall around your seedlings).
Chickens and guinea pigs will eat them (A cool idea: the chicken moat).
Keeping your garden clean
Growing fruit plants
Having chickens or ducks
Having nesting wild birds in the area
Garlic-pepper sprays have limited effectiveness
Mexican Bean Beetles
Having chicken or ducks
Onion Root Maggot
Beer traps (placing small containers of beer in your garden, allowing slugs to drink themselves to death)
Iron phosphate baits
Having chickens or ducks in the area
Egg shell barriers (sprinkling crushed egg shells around your plants) has limited effectiveness.
Shaking them off in the early morning
Waiting to plant squash until early summer
Spraying neem on their egg clusters
Removing/cleaning infected plants at the end of the season
Keeping your garden clean
Handpicking (very easy as they are large and easy to spot)
Encourage Branconid wasps, which will lay cocoons on them
Spraying with diluted dish soap
BENEFICIAL INSECTS AND ORGANISMS
Not all critters are the bad guys. These will help restore balance and prevent pest issues from getting out of control.
These will eat aphids, mites and whiteflies. You can attract them by growing daisies.
These will eat aphids by the ton. You can attract them by growing composite flowers.
These guys will dine on most garden pests.
Wasps (Ichneumon, Brachonids and Chalcids)
These will kill caterpillars the eat leaves. You can attract them by growing carrots, celery and parsley. It’s the flower of these plants that attracts them.
Good luck and stay prepared!