Inhibitory effect of Fungastop and Bion against carrot soft rot caused by Sclerotinia sclerotiorum

Abstract

This study was conducted to assess likely inhibitory effects of Fungastop™ and Acibenzolar-S-Methyl (Bion®) against carrot rot caused by Sclerotinia sclerotiorum during postharvest phase. The results showed that Fungastop was able to markedly decrease mycelial growth and sclerotia formation of three isolates of the pathogen. In addition, Fungastop significantly reduced myceliogenic and carpogenic germination of sclerotia in the three tested isolates of S. sclerotiorum. Fungastop showed high antifungal efficacy against carrot rot in vivo as carrots were inoculated with the pathogen 2.5 h after treatment with Bion and Fungastop. However inhibitory effect of Bion against the disease was higher than Fungastop over time. The enzymatic tests revealed that Bion was able to significantly enhance levels of enzyme activities related to disease resistance including β-N-acetyl hexosaminidase, endochitinase, chitin 1,4-β-chitobiosidase and β −1,3-glucanase six days after treatment. In addition, activities of phenylalanine ammonia lyase and peroxidase were markedly increased four days after treatment. Bion showed higher effect in increasing enzyme activities related to disease resistance than Fungastop. The treatment with Fungastop and Bion enhanced relative conductivity of S. sclerotiorum mycelia over 160 min compared with control. The treatment with Fungastop increased the cell membrane permeability of mycelia more than Bion.