Evaluation of Selected Nonfumigant Nematicides on Increasing Inoculation Densities of Meloidogyne incognita on Cucumber

Abstract

The southern root-knot nematode (RKN), Meloidogyne incognita, is particularly difficult to manage because of high susceptibility of all commercial cucumber (Cucumis sativus) cultivars to this nematode. Growers have conventionally relied on nematicide applications to control RKN. Two microplot experiments were conducted in which four nonfumigant nematicides, oxamyl, fluopyram, fluensulfone, and fluazaindolizine, were examined for their efficacy in reducing gall severity and postharvest soil nematode numbers in microplots inoculated with increasing inoculation densities (1,000, 5,000, 10,000, and 20,000 nematodes/microplot), and improving growth and yield of cucumber. Nematicides were applied 1 day prior to transplanting cucumber seedlings, except fluensulfone, which was applied 7 days before transplanting. At harvest, root gall indices differed significantly (P < 0.0001) among nematode inoculation densities and nematicides. All four nematicides were effective in reducing the root gall index when compared with the untreated control on a consistent basis at all M. incognita inoculation densities. At the lowest inoculation density, no significant difference in gall index or final population density was observed among nematicides; however, gall index increased with increasing nematode inoculation densities in nematicide-treated microplots. Correlations between gall index and inoculation density clearly showed that soil treatment with fluensulfone, fluazaindolizine, or fluopyram was more effective in reducing gall severity than treatment with oxamyl. Regression analysis also indicated no significant effect of nematode inoculation densities on yield of cucumber treated with these nematicides. Results of this study will provide guidance for improving nematicide efficiencies in soil with varying inoculation densities of RKN.

From Old-Generation to Next-Generation Nematicides

“…Application doses suggested by the manufacturer are in the range of 0.25-2.0 kg ha −1 , depending on the crop and application method [16]. The final population densities of M. incognita were reduced, and cucumber yields were increased, by the application of 2.24 kg ha −1 fluazaindolizine to field microplots inoculated with different levels of the nematode [109]. Fluazaindolizine at application doses of 1.12-4.48 kg ha −1 reduced the at-harvest galling of carrots in an M. incognita-infested field [77].…”

Evaluation of fluopyram for the control of Ditylenchus dipsaci in sugar beet

“…In 2014, fluopyram was registered as a seed treatment to control the soybean cyst nematode, Heterodera glycines (Beeman and Tylka, 2018). Currently available studies also demonstrated how fluopyram affects the development of the nematodes species, M. incognita, M. javanica, H. glycines, H. schachtii, and Pratylenchis loosi (Hurd et al, 2015;Kim et al, 2016;Beeman and Tylka, 2018;Mohotti et al, 2018;Dahlin et al, 2019;Hajihassani et al, 2019;Ji et al, 2019;Oka and Saroya, 2019;Schleker et al, 2019;Silva et al, 2019). This study aimed to (i) evaluate the sensitivity of D. dipsaci to fluopyram (ii), determine the effect of different concentrations of fluopyram on the penetration rate of D. dipsaci into sugar beet seedlings, (iii) determine the effect of different concentrations of fluopyram on the reproduction rates of D. dipsaci in sugar beet, and (iv) determine the optimum application strategy for fluopyram under field conditions.…”

Nematicide influence on cotton yield and plant-parasitic nematodes in conventional and sod-based crop rotation

“…Fluopyram nematicide was not effective for managing plant-parasitic nematode populations at 50 or more days after planting in this study as it had no effect on ring nematode population density and increased spiral and RN population densities at various times compared with untreated control. Previous studies have found that fluopyram can be effective against other nematodes, including root-knot nematodes on vegetables ( Hajihassani et al, 2019 ; Ji et al, 2019 ; Silva et al, 2019 ) and cotton ( Roper, 2017 ) as well as a mixture of sting nematode ( Belonolaimus longicaudatus ) and spiral nematodes on turfgrass ( Waldo et al, 2019 ). The concentration of fluopyram needed to paralyze nematodes in vitro is greater for RN than M. incognita ( Faske and Hurd, 2015 ).…”

“…While effective in managing Meloidogyne spp. on vegetables in greenhouse and microplot studies ( Hajihassani et al, 2019 ; Silva et al, 2019 ), evaluation of fluopyram effects on other plant-parasitic nematodes is needed in various rotation systems.…”