Role of Fenamiphos as a Nemastat for Control of Heterodera schachtii in Cabbage Production. P. K. Muchena, Department of Entomology, Michigan State University, East Lansing 48824. G. W. Bird, Department of Entomology, Michigan State University, East Lansing 48824. Plant Dis. 71:552-554. Accepted for publication 10 November 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0552.

The influence of fenamiphos on the sugar beet cyst nematode (Heterodera schachtii) associated with cabbage (Brassica oleracea var. capitata cv. Roundup) was studied under field conditions in clay drainage tiles. The nematicide efficacy was determined by assaying the number of H. schachtii penetrating roots. A rate of 3.6 kg a.i./ha of fenamiphos reduced nematode penetration and subsequent development for 8 wk. A split application of 3.6 kg a.i./ha at seeding and 3.6 kg a.i./ha 4 wk after seeding, or 7.2 kg a.i./ha at seeding reduced nematode penetration and development for 12 wk. Fenamiphos functioned as a nemastat by impairing the ability of second-stage juveniles of H. schachtii to penetrate roots and by slowing the rate of development of juveniles penetrating roots. Few H. schachtii second-stage juveniles survived 4–8 wk in soil treated with 7.2 kg a.i./ha or a split application of 3.6 + 3.6 kg a.i./ha, compared with soil treated with 3.6 kg a.i./ha or untreated soil. Fenamiphos application significantly increased cabbage yield by sixfold.