D. G. Milbrath of the California Department of Agriculture prepared the estimate on
the value of rejected nursery stock during the 1922–23 planting season.
Walter Carter of the Pineapple Research Institute, Hawaii, reported the nematocidal
properties of dichloropropene mixture, in 1943.
B. G. Chitwood, United States Department of Agriculture, established in 1949 that
there are many species of root-knot nematodes.
James Armstrong, California rancher, was very influential in calling the attention
of agricultural and business interests to the importance to them of improving methods
of control and reducing crop damage by nematodes. This resulted in an increase in
State financial support and the establishment of the first Department of Plant Nematology
in an Agricultural Experiment Station.