Differential Response of<i>Meloidogyne</i>,<i>Pratylenchus</i>,<i>Globodera</i>, and<i>Xiphinema</i>Species to the Nematicide Fluazaindolizine

Abstract

This research focused on the effects of fluazaindolizine on a diversity of plant-parasitic nematodes. In microwell assays, 24-h dose-response curves were generated for several species and populations of <i>Meloidogyne</i>, <i>Pratylenchus neglectus</i>, <i>P. penetrans</i>, <i>Globodera ellingtonae</i>, and <i>Xiphinema americanum</i>. In a greenhouse study, the impact of fluazaindolizine on fecundity of <i>M. incognita</i>, <i>M. hapla</i>, and <i>M. chitwoodi</i> was tested by exposing nematodes for 24 h in solution and inoculating on tomato. The average 24-h ED₅₀s (dose that resulted in the immobility of 50% of exposed nematodes) for <i>M. hapla</i>, <i>M. chitwoodi</i>, and <i>M. incognita</i> were 325.7, 223.4, and 100.7 ppm, respectively. <i>M. hapla</i> had the most variation among populations, with 24-h ED₅₀s ranging from 72 to 788 ppm. <i>G. ellingtonae</i> had the lowest 24-h ED₅₀ at 30 ppm. <i>Pratylenchus</i> spp. were unaffected by fluazaindolizine. <i>X. americanum</i> was the only species where effects of fluazaindolizine were reversible, but had a 24-h ED₅₀ that fell in the range of the <i>Meloidogyne</i> spp. In the greenhouse study, <i>M. chitwoodi</i> was the least sensitive with reproduction reaching 62% of the untreated control after a pre-exposure to 47 ppm, whereas <i>M. incognita</i> and <i>M. hapla</i> at the same exposure dose had reproduction rates of 27 and 36% of the untreated control, respectively. Despite varying in in vitro responses to fluazaindolizine, reproduction of all <i>Meloidogyne</i> spp. was suppressed after only 24 h of exposure. This study expanded our understanding of how <i>G. ellingtonae</i>, <i>P. thornei</i>, <i>P. penetrans</i>, and <i>X. americanum</i> respond to fluazaindolizine.