Biological characterization of fenpicoxamid, a new fungicide with utility in cereals and other crops

Background: The development of novel highly efficacious fungicides that lack cross-resistance is extremely desirable. Fenpicoxamid (Inatreq™ active) possesses these characteristics and is a member of a novel picolinamide class of fungicides derived from the Antifungal natural product UK-2A.

Results: Fenpicoxamid strongly inhibited in vitro growth of several ascomycete fungi, including Zymoseptoria tritici (EC₅₀ , 0.051 mg L^-1 ). Fenpicoxamid is converted by Z. tritici to UK-2A, a 15-fold stronger inhibitor of Z. tritici growth (EC₅₀ , 0.0033 mg L^-1 ). Strong fungicidal activity of fenpicoxamid against driver cereal diseases was confirmed in greenhouse tests, where activity on Z. tritici and Puccinia triticina matched that of fluxapyroxad. Due to its novel target site (Q_i site of the respiratory cyt bc1 complex) for the cereals market, fenpicoxamid is not cross-resistant to Z. tritici isolates resistant to strobilurin and/or azole fungicides. Across multiple European field trials Z. tritici was strongly controlled (mean, 82%) by 100 g as ha^-1 applications of fenpicoxamid, which demonstrated excellent residual activity.

Conclusions: The novel chemistry and biochemical target site of fenpicoxamid as well as its lack of cross-resistance and strong efficacy against Z. tritici and other pathogens highlight the importance of fenpicoxamid as a new tool for controlling plant pathogenic fungi. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Inatreq™ active; Mycosphaerella graminicola; Qi site; UK-2A; Zymoseptoria tritici; fenpicoxamid; fungicide resistance management.