Nematodes Put an End to Cucumber Season by Patty G. Leander

Posted on August 4, 2015 by Jay White

My thriving cucumber season came to an abrupt halt a couple of weeks ago. It started when a strong windstorm knocked over a cage of ‘Amiga’ cucumbers and uprooted the plants completely. All my other cages were staked so I can’t explain why this one was not but anytime you grow anything on a tomato cage, don’t forget to stake it!

Strong winds uprooted a cage of cucumbers but luckily did not damage the adjacent planting of ‘Zeebest’ okra

I was disappointed but not surprised to find evidence of root-knot nematodes on the roots (see photo). Though my plants had been producing well throughout June and early July I had begun to notice pale green leaves, misshapen fruit, reduced yields and general wilting, all signs of nematodes infestation.

Root-knot nematodes are microscopic but a heavy infestation on the roots is easily visible as swollen galls within the roots

Nematodes are soil-dwelling, microscopic, worm-like parasites that feed on plant roots, causing swelling or galls within the roots, impeding the flow of water and nutrients. They are most active in summer when soil temperature ranges between 85 and 95°F. Cucumbers, okra, squash, beans and non-resistant tomatoes are especially susceptible. Because nematodes are most active at higher temperatures they are not a serious threat to most cool season plants, the exception being carrots and beets which can have severe damage. Alliums and sweet corn are not affected by nematodes.

Most cool-season crops are not affected by nematodes but beets and carrots are an exception

Because nematodes can devastate a crop it’s important to take action if you discover them in your garden. Below are a few earth-friendly methods for battling nematodes; you may never completely eliminate nematodes but the following methods will help keep their numbers in check so that damage will be kept to a minimum. Note that nematodes can be spread by tools and soil so be sure to clean and disinfect tools after working in soil that contains nematodes, also be careful not to fling soil from infected roots to adjacent parts of the garden.

Summer Fallow: Nematodes are most active in warm soils and they need water to thrive so take advantage of summer’s heat to wither them away. Withhold water from nematode infested areas of the garden and turn or till the soil every 7-10 days during the summer to expose nematodes to the drying effects of the sun.

Crop Rotation: Plant nematode susceptible crops where non-host crops such as onions, garlic and sweet corn were previously grown.

Plant Nematode Resistant Crops: If your garden is too small for crop rotation look for plants that are bred to have nematode resistance. A tomato labeled with “VFN” indicates disease resistance: V= resistance to Verticillium wilt; F = resistance to Fusarium wilt; N = resistance to root-knot nematode resistance. Resistance doesn’t mean they won’t get nematodes but they are able to resist them enough to produce a harvest. Resistant tomato varieties include ‘Better Boy’, ‘Tycoon’, ‘Celebrity’, ‘Big Beef’, ‘Lemon Boy’, ‘Sweet Chelsea’ and ‘Supersweet 100’.

French Marigolds and ‘Pacific Gold’ mustard can be used as cover crops to reduce nematode infestation

Plant Nematode Suppressive Crops: Certain types of marigolds (Tagetes patula) work by excreting a substance that is damaging to nematodes as well as trapping them in their roots and preventing reproduction. The key is to plant the entire area as a cover crop and leave it in place for several weeks to reduce nematode populations. A late summer planting of French marigolds can be left in place right up to the first frost; effective varieties include ‘Tangerine’, ‘Petite Harmony’, ‘Petite Gold’ and ‘Janie’. At the end of the season remove the tops and turn under the roots. Elbon rye is an effective nematode control that can be planted as a cool-season cover crop that is turned under in early spring. Cut down or weed-whack the tops a couple of times during the growing season and either leave the tops in place as mulch or add them to the compost pile. ‘Pacific Gold’ mustard, also sold as Mighty Mustard®, contains high levels of compounds called glucosinolates that help suppress nematode populations. Cut down mustard before it sets seeds, add the tops to the compost pile and leave the roots to decompose in the soil. Both Elbon rye and ‘Pacific Gold’ mustard are available from Johnny’s Seeds (www.johnnyseeds.com).

Cut down or weed-whack cereal rye a couple of times during the growing season

Biological Control: In 2010, Dr. Kevin Steddom, a plant pathologist with Texas AgriLife Extension, conducted a trial at the AgriLife Research Station in Overton comparing several products for nematode control. He found that of all the products he tested, which included two soil fumigants, a biological fungicide called Actinovate was the most effective in lowering nematode populations. A 2-ounce packet sells for $18-20 but you only need ½ teaspoon per gallon and it can also be use for powdery mildew, black spot, early blight and other fungal diseases.

Secure clear plastic over very moist soil to create a greenhouse effect that will raise soil temperatures enough to kill nematodes.

Soil Solarization: Rake the soil so it is level and smooth, water well and cover with clear, UV resistant plastic (2-4 ml thick). Pull the plastic taut across the soil and secure or bury the edges with soil. Leave in place for 4-6 weeks, patching any holes with duct tape so heat cannot escape. This is often considered a last resort because the heat generated under the plastic kills everything, good and bad. It’s important to add organic matter at the end of the process; after removing the plastic do not work the soil for couple of weeks then top with a 2-3 inch layer of compost and water well before planting.

I share these posts on Our SimpleHomestead Blog Hop. Be sure to stop by. The “hop” has tons of great information from gardeners and homesteaders all over the world!

© 2012 Tomato Season Wrap Up by Bill Adams

Posted on October 14, 2012 by Jay White

There weren’t many new tomato discoveries to brag about this year. What started out as a pretty good season with low insect/mite numbers due to last year’s extreme drought combined with the blessing of occasional rains, wound down with persistent heat and a buildup of stinkbugs—both the Leaf-footed variety and the shield-shaped ones. It does seem curious that the only tomato varieties that are coming back from the spring planting are the hybrids that have nematode resistance and heirlooms that were grafted on nematode resistant rootstock (Emperador from Johnny’s Seeds). Emperador is not in the 2012 catalog but Colosus F1 is listed as a more productive replacement.

2012 was a bad year for stink bugs

The most outstanding new heirloom for us in 2012 was Marianna’s Peace. This large, somewhat oblong and cherry-red tomato had some slight folding but not a drastic amount of core typical of these large heirlooms. It had good acidity and the complex, sweet tomato flavors that we lust for in a tomato. In short it was “lap over a burger wonderful” and “lick the juice off the plate tasty”. These large fruits are produced on a potato-leaved plant and production continued into early August. This variety will definitely be tried on hybrid rootstock this year.

The most outstanding new heirloom for 2012 was Marianna’s Peace. This photo is the copyrighted property of William D Adams and cannot be published without written permission from William D Adams.

I had almost forgotten how good Juliet is. This small saladette type tomato has excellent flavor and it is extremely productive, often surviving into the fall. The skin might be a bit tough but it’s really not objectionable. Restaurants even mention it on the menu—“Bibb lettuce with Juliet tomatoes”.

Viva Italia is almost like a big sister to Juliet, great flavor, bigger and productive long into the season. Gets some Early Blight in a wet spring but usually recovers for production in late summer and fall. Fungicides can keep it productive throughout the season.

Jaune Flamme has good nematode resistance. This photo is the copyrighted property of William D Adams and cannot be published without written permission from William D Adams.

Speaking of fall—this year we planted Fourth of July a Campari style tomato (golf ball size/large clusters) with great flavor. This is one of Burpee’s best and here it produces long before Fourth of July when planted in early spring and it often lasts into late summer and fall. Planted in June/July it looks like a good fall targeted tomato.

Purple Calabash is a great black heirloom with good nematode resistance. This photo is the copyrighted property of William D Adams and cannot be published without written permission from William D Adams.

Rowdy Red is supposedly a favorite of Clint Eastwood and though not much larger than a baseball with a nipple end it has great flavor and production. Our plant is still alive in October and trying to produce more fruit. We would plant it again—maybe I’ll set an empty chair next to it for support.

Kosovo was a great tasting oxheart but the plants faded in the heat. This photo is the copyrighted property of William D Adams and cannot be published without written permission from William D Adams.

Kosovo, a big Oxheart type was a surprise. It not only grew well and was fairly productive, it tasted great too. Might have to try this one on nematode-resistant rootstock since it did fade out in the heat. Thinking about using Celebrity or Better Boy since the seed is cheaper compared to the specialty rootstock varieties from Johnny’s.

Tycoon looks like it could be our new mainstay tomato variety. Grown commercially and harvested green, is not much to brag about. But vine ripe out of the garden, it is delicious. My Champion tomatoes got ringspot virus rather quickly this year so they may not be a good main crop choice anymore where you’ve grown tomatoes for a long time. Celebrity is still a good main variety too.

Cherokee Purple is a great tasting heirloom with good nematode resistance. This photo is the copyrighted property of William D Adams and cannot be published without written permission from William D Adams.

Some other good candidates for hybrid/nematode resistant roots include Persimmon, Cherokee Purple, German Johnson, Flamme, any of the black tomatoes like Black from Tula, Purple Calabash, etc. Brandywine has been a disappointment in this area—on its own roots or when grafted. Even some standard and hybrid varieties don’t claim nematode resistance anymore—perhaps too much emphasis on breeding for virus resistance—so don’t rule them out for nematode-resistant roots either. Check out Johnny’s website for tomato grafting info, pick up some single edge razor blades and order some clips from Johnny’s.

German Johnson was another great tasing tomato with good nematode resistance. This photo is the copyrighted property of William D Adams and cannot be published without written permission from William D Adams.

The 2013 catalogs will start arriving soon. Don’t wait until after December 21 to order (word is the Mayan’s ran out of rock and scientists have found an addendum calendar rock) or you may not get the varieties you want. If you plant early (Mid-February in south-central Texas) you need to start seed in January.

Black From Tula is a great tasting slicer. Plus, it is very resistant to nematodes. This photo is the copyrighted property of William D Adams and cannot be published without written permission from William D Adams.