Baseline sensitivity and control efficacy of a new QiI fungicide, florylpicoxamid, against Botrytis cinerea

Abstract

Background: Gray mold caused by Botrytis cinerea is an airborne plant pathogen with a necrotrophic lifestyle that infects more than 200 crops worldwide. Florylpicoxamid is a second-generation picolinamide fungicide inspired by a natural product. Florylpicoxamid targets the Qi site of the mitochondrial cytochrome bc1 complex and is currently being registered in China for the control of gray mold in a variety of crops. Although a broad spectrum of activity and attributes have been reported for florylpicoxamid, little is known about its effectiveness against gray mold or its protective and curative properties.Results: Florylpicoxamid exhibited substantial inhibitory activity against 12 tested species of plant-pathogenic fungi, with effective concentration for 50% growth inhibition (EC 50 ) values ranging from 0.017 to 2.096 ∼g ml −1 . A total of 129 isolates of B. cinerea from ten regions were tested for their sensitivity to florylpicoxamid, and the mean EC 50 value was 0.04 ± 0.017 ∼g ml −1 . Furthermore, florylpicoxamid was observed to substantially inhibit all developmental stages of B. cinerea, with mycelial development, sclerotium germination, germ tube elongation and conidial germination being restrained with an EC 50 value of 0.051 ± 0.0072, 0.012 ± 0.0069, 0.019 ± 0.0041 and 0.0062 ± 0.0007 ∼g ml −1 , respectively. No crossresistance was observed between florylpicoxamid and quinone outside inhibitor (QoI), methyl benzimidazole carbamates or succinate dehydrogenase inhibitor. Florylpicoxamid also exhibited protective and curative activity against the development of B. cinerea infection in tests on tomato fruits. At application rates of 90, 112.5 and 135 g a.i. ha −1 , florylpicoxamid was also observed to provide more-effective control than boscalid (300 g a.i. ha −1 ). Conclusion:This study demonstrated that the novel fungicide florylpicoxamid exhibits strong inhibitory activity against B. cinerea, regardless of the resistance profiles of those isolates to tested fungicides with different modes of action. This makes florylpicoxamid a powerful new solution to optimize gray mold control and manage fungicide resistance.

Fungicide Effect of a Novelty Antimicrobial Biosurfactant Extract Alone or Combined with Copper Oxychloride on Botrytis cinerea Cells

“…It is important to note that all the experiments were conducted in duplicates and that the sequence of the 15 experiments was performed randomly; thus, the possibility of systematic errors was reduced. The experimental results were analyzed by means of the response surface method with the Design-Expert Version 13 software (Stat-Ease, Inc., Minneapolis, MN, USA) by fitting the experimental data to a quadratic equation, Equation (1), where y represents the dependent variable, β indicates the regression coefficients calculated by multiple regressions using the least squares method, and x denotes the independent variables. This equation is used to predict the copper bioaccumulated in B. cinerea cells in the presence of the CSL biosurfactant extract, thus providing the best fungitoxic conditions against the high-risk plant pathogen studied.…”

“…B. cinerea is commonly known for being responsible for the grey mold disease, and it is considered to be an important fungus phytopathogen that can infect around two hundred plant species, causing elevated economic losses in crops around the world [1]. It has been classified among the top ten fungal plant pathogens, occupying the second place in the ranking only after the Magnaporthe oryzae [2,3].…”

Dipicolinic acid enhances kiwifruit resistance to Botrytis cinerea by promoting phenolics accumulation

“…11 In addition, several B. cinerea strains that are resistant to common fungicides have been reported in recent years. 12,13 Bacillus species have been used extensively as biocontrol agents and exhibit direct and indirect biocontrol mechanisms to suppress the advancement of pathogens. 14,15 The direct mechanism includes the synthesis of many secondary metabolites, such as antifungal lipopeptides and polyketides, volatile organic compounds (VOCs) and cell-wall-degrading enzymes.…”

“…B. cinerea is considered one of the most hazardous fungal pathogens in molecular plant pathology and is difficult to control as it can affect a broad range of plants and tissues 11 . In addition, several B. cinerea strains that are resistant to common fungicides have been reported in recent years 12,13 …”