Root-knot nematode damage on tomato (University of Missouri Extension)
Rotation management is the primary organic method, using non-susceptible crops and varieties to decrease numbers, prior to trying some susceptible sort of heirloom tomato, for example (actually, my heirlooms are going to go in containers this year). Using trap crops such as rape seed (canola) and French marigolds is another recommended strategy.
But, beneficial nematodes that are supposedly parasitic on root-knot nematodes, sting nematodes, and ring nematodes sounded particularly appealing. The notion of having good guys take care of the bad guys in an underground soil contest, hmmm -- sounds promising to me.
So I plopped down my credit card for a supply of 5 millon Steinernema feltiae (Sf) nematodes, supposedly enough for 100-150 square feet, about the size of my main garden area. The company suggests that this variety might achieve 100% control of root knot nematodes. We'll see.
They're shipped at exactly the right time for your area, and mine arrived yesterday. More seeds, my gardening companion asked? No, it's my beneficial nematodes, I said. Woo-hoo! We'll see if they're effective at all. I hope they're hungry. I haven't been able to find a great deal of credible research information about their effectiveness, but figure it's worth a try.
Fortunately, conditions were perfect this morning for application (use immediately (√), early morning is best (√), soil should be damp (√), over 55° (√), during a rain was ideal (√), and additional watering or rain expected next few days (√).
I'm still only going to plant resistant varieties in those blocks, so this isn't a great experimental test (I suppose I could try ONE non-resistant pepper, but that gives the bad guys food). Hmrph.