SUMMARY
The effectiveness of fosthiazate (Nemathorin® 10G) was evaluated on bananas against plant-parasitic nematodes and black weevil, Cosmopolites sordidus, in four field trials in Martinique. In the first trial, two rates of fosthiazate (2.0 and 3.0 g a.i./mat) were compared with aldicarb (Temik® 10G), applied at 2.0 g a.i./mat. In the three other studies, fosthiazate, at 1.5 and 2.0 g a.i./mat applied 3 times per year, was compared with alternate applications of 3 reference nematicides: cadusafos (3.0 g a.i./mat), aldicarb (2.0 g a.i./mat) and fenamifos (3.0 g a.i./mat). A non treated check was included in all 4 experiments. Trials 3 and 4 had high levels of weevil so a standard insecticide vs. banana weevil, fipronil (0.2 g a.i./mat), was applied on the check plots. The burrowing nematode, Radopholus similis, was the dominant nematode species, followed by the spiral nematode Helicotylenchus multicinctus in trials 1, 3 and 4 whereas root-knot nematodes, Meloidogyne spp., dominated the nematofauna in trial 2 and were present at all sites. The lance nematode, Hoplolaimus seinhorsti, was only important on trial 2. Fosthiazate was as effective as the standard nematicides in trials 1 and 2 and significantly more effective in trials 3 and 4 against the burrowing nematode, R. similis. Few differences were observed in the control of H. multicinctus whereas both rates of fosthiazate significantly reduced infection by Meloidogyne spp. and H. seinhorsti. Fosthiazate was as effective against C. sordidus as fipronil. Fosthiazate treatments increased banana yields up to 35% compared to check plots by preventing toppling-over.