Management of Ditylenchus dipsaci in Daffodils with Foliar Applications of Oxamyl.

Ditylenchus dipsaci (Kühn) Filipjev is a serious pest of commercial daffodil (Narcissus sp.) in northern California. The control measures practiced by growers in recent years are postharvest treatment of planting bulbs for 3 hours in a 1% solution of formalin at 44 C combined with preplant soil fumigation with 1,3-dicbloropropene and (or) at-planting applications of phorate. In field trials, several combinations of rates (1.12, 2.24, or 4.48 kg a.i./ha in 189 liters of water/ha) and timings (one, two, or three applications at weekly intervals) of foliar applications with oxamyl on three daffodil varieties (Fortune, Ice Folley, and King Alfred) were evaluated as alternatives. Several treatments reduced nematode levels in leaves and bulbs. Phytotoxicity was not observed at any rate or combination of treatments.