Managing Nematodes in the Hoophouse



We labeled the bed where we found nematodes, to ensure good sanitation practices.

Growing in a hoophouse has all the benefits of a warmer climate and sometimes the disadvantages, such as pests and diseases not seen in outdoor crops. For us in central Virginia, winter-hardiness Zone 7, that now includes root-knot nematodes (RKN). Nematodes are tiny soil-borne worms that have a wide host range and are hard to control. They move only 3'–4' (1–1.2 m) per year on their own, but people move them on shoes, tools, etc. It’s been hard to find an organic approach to management of this pest. I’m offering what I’ve learned so far, so other growers have a starting point.

Tilling every 10 days (bare fallow) is one option, but we didn’t want "dead" soil. RKN are active at soil temperatures between 50°F–95°F (10°C–35°C), but reproduce slowly if at all below 64°F (18°C); their optimum temperature is about 90°F (32°C). At the lower end of their active temperature scale, RKN can complete a life cycle in 50 days. At 85°F–90°F (29°C–32°C) that time can be reduced to only 20 days.

Discovering Nematodes

In February 2011 we found peanut root-knot nematodes (Meloidogyne arenaria) in our hoophouse, in young spinach, which we were digging up to transplant outdoors. Some of the roots were misshapen with lumps in them. We sent a sample of plants with roots and soil to our plant diagnostic clinic at Virginia Tech and they confirmed our fears.

We formulated a two-year plan foregoing food crops for two years, using nematode-suppressive cover crops and summer solarization. Thinking we’d then be done with nematodes, we grew lettuce there the next winter. We hoped the solarization would have killed off the sclerotinia that has plagued our winter leaf lettuce. That worked well!

Subscribe Today - Pay Now & Save 64% Off the Cover Price

50 Years of Money-Saving Tips!

Mother Earth NewsAt MOTHER EARTH NEWS for 50 years and counting, we are dedicated to conserving our planet's natural resources while helping you conserve your financial resources. You'll find tips for slashing heating bills, growing fresh, natural produce at home, and more. That's why we want you to save money and trees by subscribing through our earth-friendly automatic renewal savings plan. By paying with a credit card, you save an additional $5 and get 6 issues of MOTHER EARTH NEWS for only $12.95 (USA only).

You may also use the Bill Me option and pay $17.95 for 6 issues.

Canadian Subscribers - Click Here
International Subscribers - Click Here
Canadian subscriptions: 1 year (includes postage & GST).

Facebook Pinterest Instagram YouTube Twitter flipboard

Free Product Information Classifieds Newsletters