Nasty critters the sequel: Nematodes in your garden

Published 7:10 pm Friday, July 27, 2018

Some of the nastiest critters on planet earth are the ones we can’t see. Many of us struggle with our gardens, lawns and ornamentals. We try to do everything right and somehow, we don’t get the results that we want. 

Prior to the development our microscope technology, we had no idea that there were microscopic creatures in the soil that sting the roots of plants and cause quite a bit of damage. These small microscopic round worms are called nematodes. They can have a large effect on the growth and success of many crops. There is just not one kind but many.

The root-knot nematode can be particularly troublesome to home gardeners. They feed on root cells with needle-like mouthparts called stylets. This injures the root system to such an extent that the plants can’t properly absorb water and nutrients. One female root-knot nematode can lay as many as 500 eggs at a time. Damage results from sheer numbers of nematodes feeding. Symptoms of this damage can be seen both above and below ground. These critters prefer sandy soils but are widespread throughout Georgia. 

Root-Knot nematodes can be confirmed only by examining the roots or sending them to the nematode testing lab at UGA. Look for the plants that wilt easily, look like they have a nutrient deficiency or just not doing as well as the other plants. The cost for testing the plants at University of Georgia is $12 plus shipping. 

Physically pull the plants up or dig them up to examine the roots. Both large and small roots will have many knots or galls. The root system may be shallow or stunted from the damage. The damaged roots may have also severe rotting. 

Don’t confuse the galls with the nitrogen-fixing nodules on legumes such as beans. These nodules will be on the side of the roots, generally uniform in size and pink on the inside.

If you determined that nematodes are present, what is the best course of action? The first step would be to plant resistant varieties. The seed or plant labels will indicate which are resistant to nematodes. Check out our extension bulletins as well. Keeping the plants watered, fertilized and healthy as possible will help check some of the effects of the nematodes.

If you have a contaminated area, don’t move any soil or debris to another area. It will contaminate it.  Plant crops not susceptible to nematodes in that area. Sanitize your tools including the roto-tiller tines with a 10 percent bleach solution. In severe cases you might have to relocate the garden to another spot.  Keep the area weed free as weeds may function as hosts for nematodes.

Rotating the plants on a three-year rotation will also help. It will also keep diseases at bay. Broccoli, cauliflower, grain sorghum or millet can also lower nematode numbers. Rye grown as a winter cover crop works well. 

Tilling the soil will destroy roots underground that the nematodes are feeding on. Remove old roots and destroy. Make sure you sanitize your tillage equipment as to not spread nematodes to other areas. 

Sterilize the soil by “solarization.”  Tie down a 2 to 4 mil clear plastic sheet over the affected area for at least two months. This should be done during the months of June through August. Wet the soil thoroughly before placing the plastic down. Plant a fall crop or cover crop without tilling into the soil. This procedure may work.

Increasing the organic matter, liming and fertilizing to soil test recommendations will also help reduce nematode populations by helping the beneficial nematodes provide biological control.  

What’s going on in Extension?

  • Beekeepers Meeting will be held Monday, Aug. 20 at the Extension Office at 7 p.m.
  • TCCA Meeting will be held Tuesday, Aug. 21. Topic: Improving Forages. Dinner begins at 7 p.m., cost $6, call ahead and the program begins at 7:30 p.m. at the Ag Center.
  • Market on Main: Every Saturday Morning from 8 a.m. to 10 p.m. just off the square. Come by and enjoy the pick of the day. 

If you have any questions or concerns, stop by or call the office. 

The Troup County Extension office is located at 144 Sam Walker Drive, LaGrange, GA. 30240 (706) 883-1675. It’s open Monday through Friday from 8 a.m. to noon and from 1 p.m. to  5 p.m.