Abstract
Tests were conducted in Hawaii with soils of pH range of 4.0-8.5 using: (1) soils adjusted to different pH values by addition of H2SO4 and NaOH; (2) plneapple and sugar cane field soils. In the 1st case plneapple was used for determinations of amount of root knot development; in the 2nd, both plneapple and cowpea were used. In no case was any great difference in amount of infection manifest. There is possibly a slight but unimportant reduction at pH 7.6-8.0 as compared with lower points.