A product named AzaMax. It is a liquid which one then mixes with water and sprays on he soil. I spray it on the soil before spading the garden plot and water the plot immediately afterward so that it soaks into the soil. Then, after I spade the garden up, I spray it again. Such a treatment last two to three years.

Be careful when using the product, as it is toxic. I make sure that I do not get the product on my hands or body, and I do not walk on the freshly sprayed soil until two to three days later. The treatment also gets rid of grubs, cut worms, and other harmful soil insects.

I add a lot of organic matter to my soil to keep it fertile, and nematodes flourish on soil organic matter. That makes the spraying necessary.

@wordywalt As a rose grower, I have heard a bit about the challenges of these root-rot nematodes on the Gulf Coast, most heavily in central Florida and below. For roses the strategy is to plant roses or rootstocks with especially fibrous root systems, which grow faster than the nematodes can destroy them. I know that doesn't apply to tomatoes. But I have read about predatory nematodes you can buy and release into the soil to knock down the population of the bad guys. May be less effective than your method but also non-toxic.

@MikeInBatonRouge Thanks. I'll look into that.

@wordywalt Isn't there an organic way to get rid of them or at least minimise?

@Jolanta With the heat and humidity in Florida, insects, fungi, and nematodes flourish and the soil is poor and sandy. If one wants to try vegetable gardening or farming in Florida, it is very hard to do organic gardening or farming here, unless one is willing to lose a large percentage of the yield -- and sometimes almost the whole crop -- to the pests. One can try to be conscientious about not overusing fertilizer and pesticides, but going totally organic is not practical.

@wordywalt How about aquaphonics then?

@Jolanta That would be a lot of cost and effort, the squirrels, opossums, and racoons could wreck the aquaculture arrangement. One year, I trapped 135 squirrels in my garden and had to give up trying to grow some vegetables because of the criers. Also, it took some time to find a bird feeder that was truly critter-proof

@wordywalt What did you do with the squirrels? Squirrel pie maybe?

@Jolanta some Ireleased at othr sites. Others I dispatched and used for added organic fertilizer in the garden.

@wordywalt Interesting, when I looked up azamax and read what it accomplishes, the first thing that came to mind is neem oil which it appears to be a derivative of. Have you ever tried neem oil to any effect?

@beenthere No, I have not.