Evaluation of Crop Rotation and Other Cultural Practices for Management of Root‐Knot and Lesion Nematodes

Abstract

Root‐knot [ Meloidogyne incognita (Kofoid & White) Chitwood] and lesion [ Pratylenchus penetrans (Cobb) Chitwood & Oteifa] nematodes are important pathogens that cause yield and quality losses for most vegetable and field crops in Maryland when they exceed certain threshold levels and if control measures are not applied. Chemical nematicides are the primary control tactic, but their use is both costly and raises environmental concerns. This study was conducted to evaluate the efficacy of crop rotation and other cultural practices for management of southern root‐knot nematodes (RKNs) and lesion nematodes. Three nonhost crops, a RKN‐resistant soybean [ Glycine max (L.) Merr.] cultivar, and poultry litter/tillage (Year 1) and fallow (Year 2) were used as summer rotation crops/management options following production of nematode‐susceptible crops on two sites in Dorchester County, MD, on Downer and Hammonton sandy loam soils (coarse‐loamy, siliceous, mesic Typic and Aquic Hapludults), respectively. Sorghum sudangrass [ Sorghum bicolor (L.) × S. arundinaceum (Desv.) Stapf var. sudanense (Stapf) Hitchc.], grown annually as a green manure crop following a nematode‐susceptible crop [potato ( Solanum tuberosum L.) or cucumber ( Cucumis sativus L.)], reduced the RKN population as effectively as the control treatment (soybean cultivar with no known RKN resistance and one nematicide application). Sorghum sudangrass and poultry litter/tillage/fallow were equally effective in managing the lesion nematode population. Annual inclusion of these practices was necessary to maintain the reduced population levels that were attained for these two nematode species. Finally, either summer or early‐fall sampling dates were determined to be more effective than a midspring sampling date for identifying threshold levels of these two pests.