Journal of Plant Pathology & Microbiology

Abstract

Effect of Nanoscale Silicate Platelets on Azoxystrobin-resistant Isolates of Botrytis cinerea from Strawberry In Vitro and In Vivo

Ying-Jie Huang, Pi-Fang Linda Chang, Jenn-Wen Huang, Jiang-Jen Lin and Wen-Hsin Chung

The inhibitory effect of nanoscale silicate platelets modified with different surfactants, i.e., NSS1450 and NSS3150 was evaluated for spore germination and mycelial growth of azoxystrobin-resistant (AR) and -sensitive (AS) Botrytis cinerea isolates from strawberry. The treatments with NSS1450 at the concentration of more than 50 mg/L significantly reduced spore germination by 99.2-100.0% for AR isolates and by 100.0% for AS isolates. In contrast, NSS3150 failed to show an inhibition for the spore germination of AR B. cinerea isolates. In another test, NSS1450 at concentrations higher than 500 mg/L could reduce mycelial growth by 60.2-100.0% and 93.8- 100.0% for AR and AS isolates, respectively, while NSS3150 showed similar inhibition on the spore germination. Further, NSS1450 at the concentrations between 500 to 1000 mg/L and accompanied with a fungicide, azoxystrobin, demonstrated high inhibitory rate 93.8 to 100.0% inhibition) in AR and AS isolates of B. cinerea. Under scanning electron microscope, the NSS1450 at the concentration of 1000 mg/L affected the morphologies of spores and mycelia in shrinking. The disease severity on strawberry leaves was 8.3% after 13 days incubation when treated with NSS1450 at 24 h after the pathogen inoculation. Moreover, spraying the mixture solution of 100 mg/L NSS1450 and 100 mg a.i./L azoxystrobin at 24 h after or before pathogen inoculation showed significantly efficacy compared with inoculation pathogen only. The results indicated that the silicate nanoplatelets after modification by a proper surfactant or NSS1450 had the potentials for treating gray mold disease although further studies are still needed under greenhouse and field conditions.