Answer: It sounds like nematode damage, says Tim Hartz, Extension vegetable specialist at University of California, Davis. To be sure, simply pull up a plant and look for swollen, knotted roots. The first defense is to grow resistant tomato varieties such as Celebrity, Better Boy and Beefmaster. The resistant gene is effective against many strains of nematodes, says Hartz. Nematodes are more plentiful on light soils and soils that have been continuously planted with nematode host plants, which unfortunately includes a good many vegetables. Rotate your plantings with nonhost plants like onions, marigolds, velvet beans, asparagus or calendula to reduce nematode numbers, suggests Hartz. Planting a green manure crop of annual rye in fall is also a good practice to build organic matter, while growing a non susceptible plant, he explains. Hartz has tested beneficial nematodes and fungi attacking nematode products, but his results have been inconclusive.
Q&A Library Searching Tips