EVALUATION OF POWDERED PINE BARK FOR CONTROL OF MELOIDOGYNE-ARENARIA AND HETERODERA-GLYCINES ON SOYBEAN

Commercially available pine bark nuggets (composted) and fresh pine ba rk were ground into powders and added at rates of 0 to 50 g kg(-1) to field soil infested with Meloidogyne arenaria and Heterodera glycines. The treated soil was maintained moist in the greenhouse for 2 weeks, sampled, and planted with 'Davis' soybean (Glycine max.). Eight weeks after planting, numbers of M. arenaria and H. glycines in soil decreas ed with increasing amounts of composted or fresh pine bark. No juvenil es were present in soil treated with 5% pine bark. The number of galls and cysts g(-1) root decreased in proportion to the amount of pine ba rk added to soil. Gall and cyst formation was completely eliminated at the 5% rate. Numbers of saprophagous nematodes were highest in soil w ith 4-5% pine bark. The activity of several soil enzymes was correlate d with the addition of both composted and fresh pine bark. Fresh pine bark powder caused an increase in soil enzyme activity compared to com posted pine bark, but did not provide consistent control of gall and c yst formation.