Application of pimaricin against potato white mould

Abstract

The objective of this study was to evaluate the inhibitory effect of pimaricin against Sclerotinia sclerotiorum, the causal agent of potato white mould. Field trials in 2016 and 2017 were conducted in Bahar and Lalehjin, Hamedan, Iran. Pimaricin at the concentration of 200 mg/L was able to reduce the disease incidence during field trials. The concentration of 2.5 mg/L completely inhibited the radial growth and sclerogenesis of three tested isolates of S. sclerotiorum. In addition, pimaricin at the concentration of 2.5 mg/L reduced the carpogenic germination of sclerotia in isolates 1, 2 and 3 by 100%, 88.1% and 73.9%, respectively. Treatment with pimaricin at the concentration of 2 mg/L for 160 min enhanced relative conductivity of S. sclerotiorum mycelia up to 100%. The concentration of 2 mg/L increased the cell membrane permeability of mycelia more than the concentration of 1 mg/L over 160 min. Moreover, exposure to pimaricin at the concentration of 2 mg/L for 12 hr increased carbohydrate leakage of the pathogen mycelia up to 73%. Pimaricin at the concentration of 2 mg/L markedly increased the content of methane dicarboxylic aldehyde (MDA) over time, and the highest content of MDA was recorded as 5.9 µmol/kg FW after 20 hr. The percentage of catalase activity was reduced in the pathogen mycelia by 4.1 U g−1 min−1 after exposure to pimaricin at the concentration of 2 mg/L for 20 min.