Thanks for the link Apple. I did not see that publication before but I have seen similar ones. Nematodes are a common problem here. When I had it before it was so bad that I dug out the soil and did a soil replacement.
Ginger is not nematode resistant that is why I always grow it in a large pot with fresh potting soil every year. Local ginger farms pretty much move the farm if they start getting nematodes. The other thing they do besides strict sanitary procedures is to rotate ginger with marigolds. Every other row on the farm are marigolds. When the ginger is harvested the beds are switched.
Most of the tomatoes I grow are nematode resistant anyway, but since I do like to grow some new ones and try some heirlooms, I grow the new tomatoes the same way. The tomatoes I know are nematode resistant go in the ground.
Poamoho and contender are nematode resistant beans and I have not had problems with Oregan sugar pod peas so I am thinking it probably is resistant too. Where I have had nematodes, I have confined the known areas by making sure I work those areas last and wash the tools and my shoes in pinesol disinfectant before I go anywhere else with them. I have planted the known nematode areas with crackerjack and nemagone marigolds and sunhemp. I try to avoid planting anything that is not nematode resistant in any of those areas so I actually have been practicing a rotation of sorts.
I did try solarizing, but it was not nearly as effective as the marigolds. I also have sesame that more or less grows wild.
I have found when I do have nematodes and use only resistant cultivars, the nematode counts do drop. I just have to move my non- resistant plants to clean areas of the garden or to large pots instead. After a couple of years I can usually plant the non-resistant plants in that spot again at least for a short time.
Cover crops like sun hemp and marigolds work, but the weeds cannot be allowed to grow.
The downside of sun hemp is that it is a big plant with deep roots, it is not that easy to dig out. It works great if the goal is to break up hard soil though. It is only used for animal fodder.
I always have crackerjack growing in the herb garden where there are at least 4 known spots that have nematodes. It is easy to grow, gives the herb garden a lot of color and it is prolific, so I have collected enough seed from them to last years.
Happy gardening in Hawaii. Gardens are where people grow.