FIRST REPORT OF BOTRYTIS RESISTANCE IN RED BERRIES FRUIT TOWARDS FENHAXAMID AND FLUDIOXONIL + CYPRODINIL MIXTURE, AND ITS SENSITIVITY FEATURE TOWARDS OTHER SINGLE SITE FUNGICIDES IN MOROCCO

Abstract

 In this study single spores of seven B. cinerea isolates were collected from red-berries farms in the Loukkos and Gharb regions, North of Morocco, to evaluate their sensitivity to four commercial anti-botrytis fungicides registered in the country. All four fungicides contain different active ingredients namely: Iprodione, Fenhexamid, Thiophanate-methyl and mixture of Fludioxonil and Cyprodinil. Two main experiments were established in vitro for anti-Botrytis inhibitory assay; radial mycelia growth and spore germination inhibition tests at different concentrations. Fungicidal tests showed that all strains of B. cinerea were sensitivities to Iprodione with EC50 values (the effective concentrations to cause inhibition by 50%) ranging from 0.008 to 0.34 ppm inhibiting mycelia growth, and between 0.007 and 0.27 ppm inhibiting conidia germination. However, Fenhexamid did not show the same efficacy since all strains were resistant with EC50 values all higher than 5 ppm. For Thiophanate methyl, Botrytis strains responded differently to this product. Indeed, only 12.5% of strains were sensitive. EC50 values ranging from 83.28 to 2185.66 ppm for mycelia growth and from 73.17 to 3573.01 ppm for conidia germination. However, only 37.5% of the strains have shown sensitivity to Fludioxonil + Cyprodinil mixture with EC50 values ranging from 0.01 to 67.70 ppm for mycelial growth and between 0.001 and 5.81 ppm for conidia germination. These data may explain the non-efficacy of anti-Botrytis fungicides application in gray mold control in red berries fields in Morocco and highlights the need for new strategies for Botrytis management in different red-berries culture.