Resistance of Botrytis cinerea Isolates from Vegetable Crops to Anilinopyrimidine, Phenylpyrrole, Hydroxyanilide, Benzimidazole, and Dicarboximide Fungicides

Abstract

During February 2005, 55 single-spore isolates of Botrytis cinerea were collected at the end of the season from vegetable crops grown in 18 greenhouses on the island of Crete, Greece. They were tested for sensitivity to the anilinopyrimidine fungicides pyrimethanil and cyprodinil, the hydroxyanilide fungicide fenhexamid, the phenylpyrrole fungicide fludioxonil, the dicarboximide fungicide iprodione, and the benzimidazole fungicide carbendazim. Results of the study showed the existence of benzimidazole- and dicarboximide-resistant strains at frequencies of 61.8 and 18%, respectively. Moreover, for first time, the development of resistance to anilinopyrimidine fungicides by B. cinerea was detected in greenhouse vegetable crops on the island of Crete. High resistance frequencies of 49.1 and 57.4% were observed for pyrimethanil and cyprodinil, respectively. In addition, one isolate was found to be resistant to the hydroxyanilide fungicide fenhexamid, while no strains resistant to the phenylpyrrole fungicide were detected. Among the 55 isolates tested, 13 were resistant only to carbendazim, 6 were resistant only to anilinopyrimidines, 3 were resistant to both benzimidazoles and dicarboximides, 17 were resistant to both benzimidazoles and anilinopyrimidines, 6 were resistant to both dicarboximides and anilinopyrimidines, 1 was simultaneously resistant to benzimidazoles, dicarboximides, and anilinopyrimidines, 1 was resistant to both anilinopyrimidines and hydroxyanilides, and 8 were sensitive to all fungicides tested. A strong cross-resistance relationship was found between the two anilinopyrimidine fungicides tested when log transformed EC50 values of the isolates were subjected to a linear regression analysis (r = 0.71). Despite the detection of several phenotypes with simultaneous resistance to chemically unrelated active ingredients, in none of the remaining possible fungicide pairs was there observed any kind of cross-resistance relationship.

Phenotypic Analyses of Fenhexamid Resistant Botrytis cinerea Mutants

“…In the present study, our findings suggest that the point mutation at codon 412 may confer high resistance to fenhexamid, whereas other amino acid substitutions occurring in 3-ketoreductase might confer moderate resistance, demonstrating that various amino acid substitutions in 3-ketoreductase confer fenhexamid resistance to B. cinerea. This may be the reason why B. cinerea frequently acquires fenhexamid resistance in the field (Leroux et al 2002;Barroffio et al 2003;Ma & Michailides 2005;Esterio et al 2007;Myresiotis et al 2007;Kretschmer & Hahn 2008). Therefore, it would be important to use fenhexamid in carefully designed antiresistance strategies to maintain its effectiveness.…”

Synthesis and biological activity of novel benzimidazole derivatives as potential antifungal agents

“…To mitigate crop damage caused by pests and diseases, we must utilize various crop agrochemicals, such as insecticides, herbicides, and fungicides, to control harmful insects, weed species, and plant diseases that afflict crops. However, the heavy usage of crop-protection chemicals has resulted in a number of negative impacts, such as pest resistance to pesticides, [5][6][7][8] pest resurgence, 9) and environmental pollution. 10) Benzimidazoles (especially carbendazim) have been and are still widely used to control varieties of fungal diseases, but their resistance problems may result in failure to control disease.…”

Gray mold caused by Botrytis cinerea limits grape production in Chile

“…cinerea is considered to be a high resistance risk pathogen because it produces abundant conidia as a primary inoculum, which is then efficiently disseminated. In addition, this fungus has a high genetic variability and wide host range; thus, a high number of fungicide applications are commonly required for control because of the polycyclic nature of GM (Brent and Hollomon, 2007a, b;Latorre and Torres, 2012;Myresiotis et al, 2007).…”