Susceptibility of Diploid St. Augustinegrasses to Belonolaimus longicaudatus
Busey, P.; Giblin-Davis, R.M.; Riger, C.W.; Zaenker, E.I.
Journal of Nematology 23(4s): 604-610
1991
ISSN/ISBN: 0022-300X PMID: 19283170 Document Number: 372650
A fine-textured, dwarf St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze) genotype, FX-313, was severely damaged in plots in the third year of evaluation in sandy soil in southern Florida. Damage was associated with numerous (greater than 40/100-cm3 soil) sting nematodes, Belonolaimus longicaudatus Rau. Damage was ameliorated (P less than 0.05) by fenamiphos applied broadcast at 2.2 g a.i./m2, and B. longicaudatus numbers were reduced (P less than 0.01), compared with untreated plots. Root dry weights of four diploid (2n = 18) St. Augustinegrasses--FX-261, FX-299, FX-313, and Seville--were reduced (P less than 0.001) by B. longicaudatus in a temperature- and light-controlled experiment. Estimated daily transpiration, an indicator of plant health, was reduced (P less than 0.001) after 112 days to 3.32 g/pot for inoculated plants, compared with 5.10 g/pot for uninoculated plants. Genotypes did not differ in nematode number per pot (mean 551/215 cm3 soil) 128 days after inoculation, but differed (P less than 0.05) in nematode numbers on a root dry weight basis, with FX-313 and Seville representing the extremes, 12,300 and 4,000 B. longicaudatus/g root dry weight, respectively. The diploid St. Augustinegrasses evaluated were good hosts for B. longicaudatus, but field data and controlled inoculation demonstrate genetic variation in susceptibility.