Sunflowers planted into a bean bed to attract birds and beneficial insects.
Organic Integrated Pest Management involves tackling pest problems one step at a time with ecologically-based practices, starting with actions chosen to reduce the chances of the pest ever getting a grip on your crops. You can find various listings of steps online and in print. They are all in basic agreement – start with prevention, follow with avoidance, and finish with pest-killing if needed. Here's our current flight of steps:
Cultivate a good environment for your crops: healthy soil, sufficient space, nutrients and water, suitable temperature, soil pH. Practice crop rotation to reduce the chances of pests and diseases carrying over from one crop to the next. Clear old crops promptly, so they don't act as a breeding ground for the pest. Choose suitable varieties that resist the pests you most expect.
1. Cover or protect the plants physically from the pests (mulches to stop soil-dwelling pests moving up into your crops, netting, rowcover, planting diverse crops, and even trap crops)
2. Provide habitat for natural enemies and other beneficial insects
3. Monitor crops regularly at least once a week and identify any pests you see.
4. Introduce natural enemies of the pest (bacteria, fungi, insect predators or parasites)
5. Hand pick (or trap or vacuum) and kill the pests if the pest population is above the action threshold. Many fruit and root crop plants can take 20-30% defoliation before any loss of yield. Where the crop is the foliage, this may be too much!
6. Use biological controls (often derived from natural enemies) if the damage is still economically significant after trying the earlier steps in the process.
I recommend the ATTRA online publication Organic Integrated Pest Management. Each of the 22 pages is a poster, complete with good photos and concise clear info.
From Deer, the Big Pests to Aphids, the Tiny Pests
One of our biggest garden pests is the deer, which are especially fond of sweet potatoes. We use motion-sensor water sprayers initially or in years when the deer pressure is low. For worse years we install an electric fence with a solar-powered charger. Last year our electric fence didn't keep the deer out, so this year we have a double layered fence to make sure.
At the other end of the size scale are aphids. We plant sweet alyssum in our beds of broccoli and cabbage to attract insects that will eat aphids. In early March we sow about 200 plugs for 1500 row feet (450 m) of brassicas, planted as two rows in a bed. We pop one alyssum plug in the bed centers every 4ft (1.2 m)of bed length or about one alyssum per 5 plants. We transplant these the same day that we replace any casualty broccoli and cabbage plants
For Everything In-Between: Insectaries
In late May or early June, we transplant some flowers in our vegetable garden to attract pollinators and pest predators. We use circles cut from plastic buckets to surround these clusters of flowers so that inexperienced helpers don't pull them out as weeds. We use a combination of sunflowers, dill, borage, cosmos, calendula, tithonia (Mexican sunflowers), zinnias. See my earlier post Insectaries: Grow Flowers to Attract Beneficial Insects
We also sow sunflowers about every 10ft (3 m) in our bean beds at each succession. These attract birds and pollinators, while also acting as landmarks for our harvest progress. This is especially useful when several people fan out along the bed to pick.
We plant some repellent flowers too (nasturtiums, French marigolds) and some trap crop flowers (cleome for harlequin bugs).
We transplant some bush nasturtiums in with our first plantings of cucumber and summer squash. They are said to repel some cucurbit pests such as squash bugs, but I can't vouch for that. Radishes in cucumber or squash rows are said to repel cucumber beetles and squash bugs. I haven't tried that. There are a lot of companion planting ideas out there, but most have no scientific evidence for effectiveness.
Nematodes in the Hoophouse
In our hoophouse we have been tackling nematodes for several years. In 2011 when we were digging up young spinach from our hoophouse to transplant outdoors, we found some of the roots were misshapen with lumps in them. The Plant Disease Clinic diagnosed peanut root-knot nematodes (Meloidogyne arenaria). See my earlier post Managing Nematodes in the Hoophouse.
We have tried various approaches to rid ourselves of the nematodes, including winter cover crops of wheat; spring cover crops of Lemon Drop French marigolds and Iron and Clay cowpeas; solarization in summer; fall crops of Brassica juncea mustards (Ruby Streaks, Golden Frills); and avoiding growing susceptible crops. My book The Year-Round Hoophouse contains a detailed section on dealing with nematodes, including charts of RKN-resistant crops and of varieties of various vegetable crops.
This year we have planted the nematode areas in French marigolds and sesame (apparently particularly good in deterring root knot nematodes, the type we have.) Some other nematode areas have been planted with Iron and Clay cowpeas. Unfortunately we now have an aphid infestation on the cowpeas! We are trying blasting the aphids off the plants with a strong stream of water from a hose. Later in the summer we will solarize some of the nematode areas.
Pam Dawling works in the vegetable gardens at Twin Oaks Community in central Virginia. She often presents workshops at MEN Fairs, as well as sustainable agriculture conferences. Pam also writes for Growing for Market and other magazines. Her books, Sustainable Market Farming, and The Year-Round Hoophouse are available at www.sustainablemarketfarming.com. Her blog is on her website and also on facebook.com/SustainableMarketFarming.
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