Organic Pest Control

The thought of having to control pests organically seems to intimidate a lot of people. Myth has it that we don't use pesticides or herbicides. There are visions of us out in the field picking bugs off plants for hours on end. Sure, we do hand-pick some pests, and that works well at times, but that's not all we do. Let's clear these things up and discover how simple organic pest control really can be.

Barriers

It's easy to protect a lot of plants from pests. Floating row cover is a great tool in pest control. I use Agribon because it's light weight but still tough enough to last two years with proper care. Some pests, like flea beetles and the hairy chinch bug, overwinter in the soil. Placing a row cover over plants affected by them won't stop these pests but it can help keep others from moving in. Row covers also help prevent insect borne diseases by limiting the amount of pests that attack a plant. Don't forget to remove row cover when plants that don't self pollinate are in bloom. Pollinators need access to the plants.

Barriers come in liquid form too. Garlic and hot pepper oils mix with water and are sprayed on the plant. They make the plant distasteful to pests. Tanglefoot forms a barrier that keeps insects from climbing to the tops of trees to mate and lay eggs. They become trapped in the sticky tanglefoot and can't get out. Diatomaceous earth forms a sharp barrier that slugs won't cross. These barriers need to be re-applied after rain. Copper is an interesting barrier. The slimy coating over slugs and snails creates a shock when it touches the copper. You can see them recoil.

Early Planting

I try to get as many of the cool weather crops planted as early as possible. I can usually harvest most of the brassicas before cabbage worms are a problem. By the time most of the moths are here the vegetables have been sold and the plants are in the compost pile. The words "as soon as the soil can be worked" can mean "before the pests wake up." Insect life cycles are slowed by cool soil and weather conditions.

Crop Rotation and Diversity

A diverse field allows for crop rotation. Move your potatoes and other night shades as far away from last year's planting area as possible. And if you can, don't bring them back to a place they've been growing for at least three years. Look for problems. If you pull a plant and find a problem with something like club root, plant a resistant crop there the next crop or year.

Integrated Pest Management

Integrated pest management, commonly called IPM, combines predators and parasites with prey. Lady bugs and praying mantids are predators that feast on aphids, mites, scale and other undesirables. Green lacewings are an interesting predator. Before they eat their pray they paralyze it, then they suck out the body fluids. I like to think of them as gardening's vampires. A single lacewing will eat as many as 200 aphids a week. Parasitic insects are as gruesome and interesting as lacewings. Parasitic wasps lay their eggs in soft-bodied pests like hosts such as tomato hornworm, European corn borer and codling moths. The eggs hatch, the host dies and the parasite eats the host. If you decide to try IPM you should spend time researching the correct parasite or predator for the pest(s) you have, and find out the conditions under which you should release them.

Trap Crops

Planting trap crops isn't a new idea but it's one I don't see in use very often. They lure pests away from your valuable crop. Blue Hubbard squash works well for striped cucumber beetles. I plant radishes at the edge of the broccoli rows and let the radishes go to seed when I plant my second crop in early August. Trap crops don't trap all of the pests but they do make drastic differences in the number of pests on your cash crops. It's easier to manage a high concentration of pests with an insecticide than to have them spread out over the cash crop. Trap crops should always be planted on the perimeter of the field.

When Pests Take Control

There are many organic pesticides available. When the pests take control of the garden it's time to pull out the pesticides. All pesticides should be used according to the directions provided with the product. Match the pesticide to the pest. This hasn’t been written as a guide to what to use but as general information on some of the organic pesticides available.

Neem Oil works by clogging the pest's pores, causing suffocation. It also slows feeding to cause starvation and interferes with molting. It is best used on immature insects. It must be reapplied often while you have a pest problem because it breaks down in sun and is easily washed away. It isn't a fast acting insecticide. Don't be discouraged if you still have pests the next day.

Insecticidal Soap works by damaging the protective coating on soft-bodied insects. This causes them to dehydrate and die.

Pyrethrum paralyzes pests fairly quickly. It doesn't cause an immediate death but does stop them from causing damage quickly.

Bacillus Thuringiensis comes in many subspecies. It is commonly called Bt. Each subspecies treats specific pests. They kill beetles, moths, butterflies, mosquitoes, blackflies and many of the usual garden pests. Read the label to find out which subspecies you need.

Beneficial Nematodes are very safe to use. They small worm-like parasites that are used in the soil. They attack cutworms, borers, mole crickets and more. They're a little tempermental so be prepared to use them when you get them. They like high humidity, moisture and shade. Like Bt, there are subspecies of nematodes and it's important to find the correct one.

Boric Acid is used for ants, roaches, crickets and silverfish. It's a stomach poison that kills pests by starving them to death.

A False Sense of Safety

Don't be lulled into a false sense of absolute safety when using organic controls. Even natural methods can cause problems. Use them responsibly by using them according to the directions and only when necessary. Remember, using more isn't better. Use only what is needed to get the job done. And don't forget to hand pick because it is after all, what organic growers do!