Research Papers: Use of Mixtures of Urea and Blackstrap Molasses for Control of Root-Knot Nematodes in Soil

Abstract

Additions of urea to soil at rates of 0.4 g/kg soil or higher resulted in significant reductions in numbers of galls per g of fresh root of squash (Cucurbita pepo) caused by Meloidogyne arenaria. These rates of urea resulted in significant accumulations of nitrate and ammoniacal N in soil, increased conductivity of soil water extract and phytotoxicity to squash plants. Application of mixtures of blackstrap molasses with urea to soil resulted in improved control of M. arenaria, no significant accumulation of nitrate or ammoniacal nitrogen and no phytotoxicity to plants. The molasses + urea treatments resulted in increased urease and invertase activity of the soil and, for concentrations of urea of 0.4 and 0.8 g/k soil, in increased numbers of microbivorous nematodes.