MANAGEMENT OF PRATYLENCHUS-PENETRANS ON ORIENTAL LILIES WITH DRIP ANDFOLIAR-APPLIED NEMATICIDES

Pratylenchus penetrans is a pest for producers of oriental lilies in n orthern California. Concern over groundwater contamination from 1,2-di chloropropane following shank injections of 1,3-dichloropropene-1,2-di chloropropane mixture and granular applications of aldicarb prompted t esting for alternative methods of controlling P. penetrans. In field t rials, nematicides applied by drip irrigation (ethoprop, fenamiphos, o xamyl, sodium tetrathiocarbonate, water extracts of marigold and vetch , and 1,3-D plus emulsifier) were tested with and without foliar appli cations of oxamyl. Nematode populations were reduced (P = 0.05) relati ve to controls in soil or roots on one or more sampling dates by all d rip-applied nematicides except the plant extracts. On some sampling da tes, additional reductions (P = 0.05) occurred as a result of three fo liar applications of oxamyl. Foliar-applied oxamyl alone also reduced (P = 0.05) nematodes in soil or roots. Lily bulb weight was not affect ed (P = 0.05) by chemical treatments.