Population dynamics and crop yield effects of nematodes and white mold in peanuts, cotton and velvet beans

Dynamic population equations for the root-knot nematode (Meloidogyne arenaria), Southern blight ('white mold') fungus (Sclerotium rolfsii), and microbivorous nematodes in peanuts, cotton, and the Alabama velvet bean were statistically estimated with replicated experimental data from Headland, AL, USA. The level of microbivorous nematodes the previous crop year was found to suppress the root-knot nematode and white mold in peanuts the following crop year in monoculture peanut production and in peanuts after velvet beans. Statistical results showed that both the root-knot nematode and white mold had a negative effect on peanut yield, while microbivorous nematodes had a positive effect on peanut and cotton yields. Scientific knowledge of these organisms does not fully explain the results, but the statistical results strongly suggest that these relationships exist. On the basis of statistical results for peanuts, each white mold occurrence (in a 60-ft row) cost $21.41, each root-knot nematode (in 100-cm3 soil sample) cost $0.41, and each microbivorous nematode (in 100-cm3 soil sample) had a benefit of $0.11. In cotton production, microbivorous nematodes had a benefit of $0.13.

Duke Scholars

Author Curtis R. Taylor Economics