EFFECT OF ALDICARB, ALDOXYCARB AND OXAMYL ON POTATO TUBER YIELDS AND ROOT LESION NEMATODES

In a 3-yr field study at Upton, Prince Edward Island, aldicarb at 1.12 and 2.24 kg a.i. ha−1 and oxamyl at 2.24 kg a.i. ha−1 were applied in the furrow with seed potatoes. Nematicide treatments increased tuber yields of Superior by 15.5% (4.6 t ha−1) and yields of Russet Burbank by 9.3% (3.4 t ha−1). Shepody did not respond to nematicide treatments. The effect of aldicarb on average yields of all three cultivars did not differ from that of oxamyl, nor did yields at the higher rate of aldicarb differ from those at the lower rate. In a two-year field study at Harrington, Prince Edward Island, aldicarb and aldoxycarb applied at a rate of 2.24 kg a.i. ha−1 increased yields of Superior by similar amounts of about 40% (9.4 t ha−1). Oxamyl applied at the same rate in the second year had the same impact on yields as aldicarb or aldoxycarb. Nematicide treatments reduced the numbers of root lesion nematodes (primarily Pratylenchus penetrans) in roots and soil at Upton. Both rates of aldicarb had a similar impact, but oxamyl was less effective than the aldicarb treatments in reducing nematode numbers in roots. At Harrington, aldicarb controlled nematode populations more efficiently than aldoxycarb in soil in the first year and in roots in the second year. Aldoxycarb and oxamyl reduced nematode populations to a similar degree.Key words: Aldicarb, aldoxycarb, oxamyl, Pratylenchus penetrans, Solanum tuberosum