EVALUATION OF FOSTHIAZATE FOR THE SUPPRESSION OF PHYTOPARASITIC NEMATODES IN TURFGRASS

Two formulations of fosthiazate (10G and 7.5 EC) were compared with fe namiphos 10G for control of phytoparasitic nematodes in fairway manage d bermudagrass in two field experiments in southern Florida in 1990 an d 1991. Fosthiazate was applied at 1.5 and 2.2 g a.i./m(2) in the 1990 experiment and 0.7 and 1.5 g a.i./m(2) in 1991. Fenamiphos was applie d at 2.2 g a.i./m(2) both years. In the 1990 study, both formulations and rates of fosthiazate were as effective as or more effective than f enamiphos 10G in reducing soil populations of Belonolaimus longicaudat us and Meloidogyne spp. and in improving turfgrass quality ratings for 56 days post-treatment. In the 1991 study, both formulations of fosth iazate at 1.5 g a.i./m(2) were as effective as fenamiphos 10G in impro ving turfgrass quality ratings for 56 days post-treatment. In a labora tory pot experiment, fosthiazate 10G at 1.5 g a.i./m(2) was compared w ith fenamiphos 10G at 1.1 g a.i./m(2) for suppression of B. longicauda tus on FX-313 St. Augustinegrass. Both nematicides markedly suppressed population expansion of B. longicaudatus and prevented root dry weigh t loss. Fosthiazate was marginally phytotoxic to St. Augustinegrass.