Sensitivity to fungicides of Botrytis cinérea (Pers.) isolated from raspberry (Rubus idaeus L.)

Abstract

Objective: To evaluate the sensitivity of B. cinerea isolated from raspberry to nine fungicides alone and in combination with potassium silicate. Design/methodology/approach: The study evaluates the sensitivity of four isolates obtained from four raspberry plantations in October 2022, which were identified in a previous study as B.cinerea based on morphological, morphometric and molecular characteristics, to nine fungicides alone and combined with potassium silicate. B. cinerea was planted in PDA culture medium modified with fungicides plus potassium silicate, and mycelial growth and mycelial growth inhibition percentage (PICM) were evaluated. A completely randomized design with six repetitions and two controls was used, an ANOVA and Tukey’s mean comparison test were performed. Results: B. cinerea isolated from CITAP showed lower growth with fluazinam (PICM = 100 ), while with azoxystrobin it presented a PICM equal to 0. B. cinerea isolated from Paso del Cristo and Sierra Negra 2 had lower growth with fluazinam (PICM = 100), while with boscalid and azoxystrobin it showed a PICM equal to 0. In Sierra Negra 1, iprodione controlled B. cinerea better with a PICM equal to 100, while azoxystrobin showed a PICM equal to 0. All the isolates were sensitive when fungicides were combined with potassium silicate. Findings/conclusions: All the isolates were sensitive to the fungicides fluazinam, fenhexamid, thiophanate methyl, captan, pyrimethanil, fludioxonil and iprodione. The isolates from Sierra Negra 1 and CITAP were sensitive to boscalid, while those from Sierra Negra 2 and Paso del Cristo were insensitive; 100 % of the isolates were insensitive to azoxystrobin, which suggests that they could be resistant; finally, potassium silicate potentiates the effect of fungicides.