Disease Note.

First Report of Hoplolaimus magnistylus on Kenaf in Mississippi. G. W. Lawrence, Department of Plant Pathology and Weed Science, Mississippi State University, Mississippi State 39762. K. S. McLean, and B. S. Brasher. Department of Plant Pathology and Weed Science, and Department of Agricultural Economics, Mississippi State University, Mississippi State 39762. Plant Dis. 74:828. Accepted for publication 8 April 1990. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/PD-74-0828A.

The lance nematode (Hoplolaimus magnistylus Robbins) was recovered from kenaf (Hibiscus cannabinus L.), an annual fiber crop, in Tallahatchie County, Mississippi, in 1989. Population densities of 460 and 50 H. magnistylus were recovered from 250 cm³ of soil and 1 g of kenaf roots, respectively. Pathogenicity tests were conducted in the greenhouse by inoculating 5-day-old seedlings of kenaf cv. Tainung I with 113 juvenile and adult H. magnistylus in 500 cm³ of soil. Plant growth and nematode populations were measured after 60 days. Shoot heights and weights were suppressed and root weights were reduced (P = 0.05) by 49% in nematode-infested soil as compared with nematode-free soil. The population density of H. magnistylus increased 972% with a reproductive factor (final population/ initial population) of 10.7. Adults, juveniles, and eggs were observed in the roots, and an average of 45 nematodes were recorded per gram of fresh root. The increase in nematode population and suppression of plant growth confirm that kenaf is a susceptible host for H. magnistylus.