Because root-knot nematode is unable to reproduce on resistant tomatoes, planting them is equivalent to utilizing fallow for the same length of time, thus allowing nematodes to starve to death.
In the cotton experiment, the year following a susceptible tomato crop, susceptible tomatoes were grown following fumigation and resistant tomatoes were grown without fumigation.
At harvest, populations following resistant tomatoes were less than half those following fumigation/susceptible tomatoes.
In the third year of the experiment, cotton was grown with and without fumigation following the two earlier treatments.
Yields were equivalent in all treatments except the cotton grown without fumigation following fumigation/susceptible tomatoes.