Got Nematodes In Your Garden?Nematodes can be beneficial to plants, but in large numbers, they do more damage than good. I hate to throw my fellow soil-dwellers “under the bus,” so to speak, but it is only fair that I notify hard-working gardeners about the soil life that shares my home down below (more of that “worms eye view” that only a garden gnome can give you). In order to ensure that your soil is healthy and friendly to everything that lives in it, you need to know a bit about each living thing. What are Nematodes?They are small animals that look like worms, but are much different, physiologically. For one thing, they are tiny — the largest are only 4 mm in size. If you suspect a nematode problem in your soil, you will probably have to have a soil sample inspected by an extension agent with a microscope. Varieties that are parasitic to plants, we’ll call them the bad guys, have stylets, which are spear-like mouth parts that they use to take in food.In general, they like to eat microscopic plants and animals, though sometimes they really start to go to town, devouring plant roots. This causes a problem for two reasons:
Where Do They Live?They call the soil home for most of their life cycle. They are most highly concentrated in areas near plant roots. This is because they reproduce quickly in the overabundance of food. (Have you heard the term “reproducing like rabbits?” Well, “reproducing like nematodes” is more accurate, in terms of population growth.They spend most of their lives in the top 15 to 30 cm of soil. They spread fairly slowly, because they move under their own power, and they are small and not fast. Occasionally, they will hitch a ride through irrigation water, flood-waters or animal feet. Recognizing Nematode DamageThe first step to a cure is recognition of the problem. (When I manage to hoist myself onto the windowsill and sneak a few minutes of human television, it seems that every self-help show endlessly repeats that mantra. Anyway, if you have a nematode problem in your soil, you may see the following problems in your plants:Turfgrass: If you have a nematode problem in your lawn, your grass will appear yellow and weak. During periods of drought, it will wilt. If bad guys are chomping on the grass roots, you will be able to lift up patches of grass with very little difficulty. Trees: Trees will show nitrogen deficiencies because of the yellowing of the leaves that will occur. (This is why I am always telling you to have your soil tested! Most problems start in the soil. I should know. I live there!) In addition to yellowing, the tree’s growth will also be stunted. Vegetables, Annuals and Perennials: If your veggies, annuals and perennials are looking puny above ground, dig up one or two, or dig around the roots. If they are infected with bad guys, they are probably going to have knotty growths on their roots. Some cause little cyst-looking growths, while others make root-crops like beets and carrots grow lots of small, hairy roots when they should be smooth. How To Eradicate ThemThe bad guys are no fun. They can pretty much ruin your production of root crops, while they wreak equal havoc on your yard and flowerbeds. If you suspect you have a bad guy problem, first take a few soil samples and have them tested. (Take it from me, living down here with a bunch of other critters—you don’t want to treat a problem you don’t have. It is expensive, and you could kill a bunch of beneficial creatures.) If a soil test shows an overpopulation of the bad guys, you need to next take the following steps:
Happy gardening, Geefrank
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