Biotic and abiotic resistance inducers for controlling white rust in rocket (Eruca sativa)

Abstract

Induced resistance emerges as an alternative method for controlling plant diseases. This study aimed to evaluate the efficacy of biotic and abiotic resistance inducers for controlling white rust in rocket (Eruca sativa), as well as biochemical changes (peroxidase) and fitness costs. The experiments were developed with the abiotic inducers acibenzolar-S-methyl (ASM) (12.5, 25, and 50 mg ai L-1) and citrus biomass (CB) (0.1, 0.25, and 0.5%), as well as with the biotic ones Saccharomyces cerevisiae (25 mg mL-1), Bacillus thuringiensis (25 mg p.c. mL-1), Saccharomyces boulardii (25 mg mL-1), and phosphorylated mannan oligosaccharide (PMO) (0.25%), in preventive and curative interventions. Fungicide mancozeb (1.6 g ai L-1), Bordeaux mixture (1%), and water were the control treatments. Leaf samples were collected 3, 7, 11, 15, and 19 days after the treatments to determine peroxidases and assess the severity and production. Concerning abiotic inducers, all doses of ASM and CB 0.5% (preventive) and CB 0.25% (curative) reduced the severity of white rust, whereas, among biotic inducers, only PMO applied preventively controlled the disease. Peroxidase activity was higher for CB 0.25% and ASM 50 mg L-1. Bordeaux mixture induced higher peroxidase activity.