Evaluation of some fungicides on mycorrhizal symbiosis between two Glomus species from commercial inocula and Allium porrum L. seedlings

Abstract

This paper reports the effect of twenty-five commonly used fungicides in agriculture on two arbuscular mycorrhizal fungi (AMF) present in commercial products of ATENS, S.L.: Glomus intraradices (Schenck & Smith) and Glomus mosseae [(Nicol. & Gerd.) Gerdemann & Trappe], forming the symbiosis with leek plants. Systemic fungicides (Aliette, Beltanol, Caddy 10, Forum, Moncut, Ortiva, Previcur, Ridomil Gold MZ, Ridomil Gold SL, Rubigan, Sinthane, Stroby, Swich, Tachigarem, Teldor, Topas 10 EC, Frupica) and non systemic fungicides (Daconil 75%, Ditiver, Euparem, INACOP, Octagón, Parmex, Terrazole and Metaram), started to be applied to soil and leaves at recommended concentrations and frequencies 4 weeks after transplant and AMF inoculation. The effect of the fungicides was assessed by comparing treated and untreated plants that were inoculated with the AMF through quantification of root mycorrhizal colonization. Among the fungicides applied to the soil, Octagon, Ditiver, Parmex and Metaram virtually eliminated the mycorrhizal symbiosis in treated plants, while the mycorrhizal colonization was not affected by the soil treatment with Beltanol, INACOP and Previcur. Three fungicides of foliar recommended application: Rubigan, Frupica, and Sinthane, strongly inhibited mycorrhizal colonization, but Aliette, Forum, Teldor, Swich and Ortiva, did not seem to reduce it substantially. In addition, the work describes the individual effect of each fungicide applied on both, foliage and soil.

Why farmers should manage the arbuscular mycorrhizal symbiosis

“…(2) Ryan & Graham () do not include agrochemical effects in this discussion. However, fungicides (foliar applications and seed treatments) can reduce AM fungal spore germination, mycorrhiza formation, AM fungal community composition, extraradical hyphae and/or spore production (Dodd & Jeffries, ; Merryweather & Fitter, ; Wilson & Williamson, ; Hernandez‐Dorrego & Mestre‐Pares, ; Ipsilantis et al ., ; Jin et al ., ; Buysens et al ., ; Lekberg et al ., ). (3) Plant breeding in the future should occur in environments that favor interactions of plants and AM fungi (reviewed in Bennett et al ., ).…”

Modern Fungicides: Mechanisms of Action, Fungal Resistance and Phytotoxic Effects

“…[72]. But in another case, fludioxonil had no significant effect on the colonization of AMF in onions [73]. Thus, the potential negative effects of systemic and contact fungicides on non-targeted, useful AMF are not fully understood and studied [71].…”

Arbuscular mycorrhizal fungi and their response to pesticides

“…However, when Cu‐based products were applied to the soil, root colonization was not affected or was only moderately affected (Table S1). Thus, the use of Cu‐based plant protection products appears to be compatible with AMF due to the strategies evolved by AMF for Cu‐contaminated environments. Nevertheless, AMF can reduce the negative effects exhibited by Cu toxicity on the host plant.…”