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Disease Control and Pest Management

Inhibition of Criconemella xenoplax Egg Hatch by Pseudomonas aureofaciens. S. W. Westcott III, Assistant and associate professor, Department of Plant Pathology and Physiology, 120 Long Hall, Box 340377, Clemson University, Clemson, SC 29634-0377; D. A. Kluepfel, associate professor, Department of Plant Pathology and Physiology, 120 Long Hall, Box 340377, Clemson University, Clemson, SC 29634-0377. Phytopathology 83:1245-1249. Accepted for publication 11 June 1993. Copyright 1993 The American Phytopathological Society. DOI: 10.1094/Phyto-83-1245.

Nine fluorescent pseudomonad strains and one strain each of Escherichia coli and Rhizobium fredii were tested for potential to inhibit Criconemella xenoplax egg hatch. One strain, Pseudomonas aureofaciens BG33, and its genetically modified derivative, BG33CL1R, effectively inhibited egg hatch at 2.0 × 10⁸ cfu ml^–1. Strain BG33CL1R inhibited egg hatch by 5, 50, and 95% when present at 1.0 × 10⁷, 4.8 × 10⁷, and 2.4 × 10⁸ cfu ml^–1, respectively. Eggs were sensitive to BG33CL1R from the time of deposition until second-stage juveniles were formed inside eggs 6.5 days later. In contrast, activity of second-stage juveniles and adults did not appear to be affected by incubation in BG33CL1R for up to 2 wk. Seven strains of P. aureofaciens and one strain each of E. coli, P. chlororaphis, and R. fredii did not inhibit egg hatch in similar tests. Therefore, general septic conditions apparently are not responsible for egg kill. The potential for P. aureofaciens BG33 and BG33CL1R to kill C. xenoplax eggs could explain in part their suppression of nematode population increase in greenhouse tests.