In a field trial which started at planting, Radopholus similis was controlled by fensulfothion applied at 2.0 g a.i. stool-1 in June and December each year for 4 years. Ethoprophos, fenamiphos and oxamyl applied at the same rate and times were less effective but they did reduce the rate of increase in numbers of nematodes. All treatments increased yields, especially in the third and fourth bunch cycles. The increase was due to larger bunches and to fewer plants falling over. Yields over the entire period were increased by 44% with fensulfothion, 29% with fenamiphos and ethoprophos, and by 21% with oxamyl. In three further trials which were started in the second or third bunch cycles, fenamiphos applied at 2.0 g a.i. stool-1 six times a year gave better nematode control than when it was applied three times a year, or than ethoprophos applied at 6.0 g a.i. stool-1 twice a year. Yields were increased by up to 60%.