A survey was undertaken to determine the frequency and abundance of plant-parasitic nematodes associated with cotton (Gossypium hirsutum L.) in Alabama. In the fall seasons of 1998-2000, 969 soil samples were collected from cotton fields representing 8613 ha, or 4.3% of the cotton hectares in the state. Composite soil samples were collected from 8 ha in each field. Nematodes were extracted by gravity screening and sucrose centrifugation, identified to genus, and quantified. Eleven genera of plant-parasitic nematodes were identified. Rotylenchulus reniformis was found in 46% of the fields sampled. Percentages of fields with low, moderate, high, or very high populations of juveniles and vermiform adult stages per 100 cm3 were 44%, 9%, 14%, and 33%, respectively. Meloidogyne incognita was identified in 7% of the fields sampled. Percentages of fields with low, moderate, and high populations of juveniles of M. incognita per 100 cm3 were 57%, 16%, and 27%, respectively. Hoplolaimus columbus was identified in 0.3% of the fields surveyed. Rotylenchulus reniformis occurred at population levels above the economic threshold in 47% of the infested fields. Meloidogyne incognita, although found less frequently, was found above the economic threshold in 70% of the fields infested. This survey indicates that Rotylenchulus reniformis and Meloidogyne incognita are widespread in the cotton production regions of Alabama and nematode management strategies must become a part of production practices.
