Nematicide efficacy at managing Meloidogyne arenaria and non-target effects on free-living nematodes in peanut production

Abstract

Meloidogyne arenaria (peanut root-knot nematode (PRKN)) is a major pest of peanut. Nematicide application is an important tool for the management of PRKN. Nematicides with minimal effects on free-living nematodes are desired. Fluopyram nematicide is recently introduced in peanut production and needs to be assessed. The objective of this research is to evaluate fluopyram and the established nematicides 1,3-Dichloropropene (1,3-D) and aldicarb for efficacy at managing PRKN and impacts on free-living nematodes. Nematicides were evaluated in field studies in 2017 and 2018 conducted in commercial peanut fields. All nematicides increased peanut yield in 2017 compared with untreated control, but did not affect soil PRKN abundances or root galling. In 2018, PRKN infestation was too low to accurately assess PRKN management by nematicides. Aldicarb and fluopyram did not affect any free-living nematode trophic group or individual genera. In contrast, 1,3-D decreased total fungivore and fungivore genera Filenchus and Aphelenchus soil abundances, but did not affect bacterivores, omnivore-predators, total herbivores, or any other nematode genera. In summary, 1,3-D, but not aldicarb or fluopyram, had non-target effects on free-living nematodes, particularly fungivores.

From Old-Generation to Next-Generation Nematicides

“…Fluopyram-based products are currently registered for many crops and associated nematodes, depending on the country and crop, including Belonolaimus longicaudatus, Globodera rostochiensis, Globodera pallida, Helicotylenchus spp., Heterodera spp., Longidorus spp., Meloidogyne spp., Pratylenchus spp., Radopholus similis, Tylenchulus semipenetrans, and Xiphinema spp. In field trials, 0.24 kg ha −1 fluopyram did not reduce M. arenaria populations, although it increased the peanut yield in one of two field trials [90]. In fields infested with M. incognita, 0.256 kg ha −1 fluopyram reduced the galling index for carrots, but not the total yield [77].…”

“…Fluopyram was found to reduce the number of free-living nematodes for a long period (up to 238 days after application), especially bacterivores, fungivores, and omnivores, and to have the potential to affect all nematode feeding groups [66]. In peanut fields, 0.24 kg ha −1 fluopyram did not affect any free-living nematode trophic groups or individual genera, although the same treatment also did not reduce the population of Meloidogyne arenaria [90]. In a study on the soil microbial activity, fluopyram (0.5-5 mg kg −1 soil) decreased total phospholipid fatty acids, the biomass of both gram-negative and gram-positive bacteria, the fungal biomass, and the microbial community structure in the soil [91].…”

Effects of fluopyram and azadirachtin integration with sunn hemp on nematode communities in zucchini, tomato and sweet potato in Hawaii

“…Only limited studies have documented the effects of fluopyram on free-living nematodes. Grabau et al (2020) reported no effect of fluopyram on any free-living nematodes on peanuts ( Arachis hypogaea ), but Waldo et al (2019) found fluopyram had a substantial negative impact on free-living nematodes in bermudagrass ( Cynodon spp.). Our findings are in line with that of Waldo et al (2019) that fluopyram alone would suppress free-living nematodes including bacterivores, fungivores and omnivores that are important indicators of soil health.…”

Texas Root-Knot Nematode Meloidogyne haplanaria Eisenback et al. 2003 (Nematoda: Chromadorea: Chromadoria: Rhabditida: Rhabditina: Tylenchomorpha: Meloidogynidae)

“…Texas root-knot nematode is capable of limiting yield of peanut in nematode-infested soils, but was less aggressive than the more widely distributed parasites of peanut, Meloidogyne arenaria and Meloidogyne javanica (Bendezu et al 2004). The peanut cultivar 'NemaTAM' , which has been bred for resistance to Meloidogyne arenaria and Meloidogyne javanica (Simpson et al 2003), is also resistant to Texas root-knot nematode (Bendezu et al 2004); however, the resistant cultivars are not widely adopted due to lack of seed supply of the resistant cultivars, lesser yield potential, and high susceptibility to Tomato spotted wilt virus (Dong et al 2008, Grabau et al 2020. The resistance in tomato to Meloidogyne arenaria, Meloidogyne javanica, and Meloidogyne incognita conferred by the Mi gene is not effective against Texas root-knot nematode (Bendezu et al 2004).…”