Field trials were undertaken with a prototype machine to determine whether virus vector nematodes and aphids were controlled by the carbamoyl oxime pesticides aldicarb (Temik 10G) and oxamyl (Vydate 10G) incorporated into the ridge of a growing potato crop. The treatments were applied at tuber initiation (7 or 8 weeks after planting) and were compared with similar amounts of the same pesticides applied in-furrow at planting. All aldicarb treatments significantly decreased the incidence of tobacco rattle virus spraing transmitted by trichodorid nematodes. However, the side-banded treatments were less effective than the in-furrow treatments applied at similar rates. Numbers of aphids infesting the crop were significantly and similarly decreased by both methods of application. Pesticide treatments did not significantly increase yield, and total tuber yields from the standard infurrow and the side-banded treatments were similar. To provide further information on the efficacy and movement of carbamoyl oxime pesticides between different isolated root systems on single parent tubers, replicated pot experiments were made. Parent tubers were maintained with a physical barrier between a root system treated with pesticide and another left untreated. In a nematode bioassay Meloidogyne incognita was added to both the treated and untreated root systems to test for the presence of nematicidal activity. The number of root-galls which developed in 8 weeks were counted. Both aldicarb and oxamyl decreased the number of galls on the treated root system. However, little evidence of translocation through the parent tuber was found, the number of galls on the untreated roots being largely unaffected. The roots of plants grown from tubers treated in a similar manner were tested for the presence of aldicarb and oxamyl residues by gas-liquid chromatography. No translocated pesticide was detected. In aphid bioassays, using excised leaves, 3–5 weeks after applying aldicarb at 20 and 40 mg a.i./pot or 4–9 weeks after applying aldicarb at 80 mg a.i./pot, aphid survival was always significantly less on treated stems than on non-treated stems growing at the opposite end of the tuber or on control stems growing from untreated tubers. However, there was some evidence for translocation through the parent tuber as fewer aphids survived on leaves from non-treated stems than from untreated control stems.