BTH-induced resistance to Alternaira alternata f. mali in apple
WANG Wen-juan, ZHAO Jian-zhuang*, WEI Chao-jun, WANG Chun-na, JIA Lin-fang, WANG Jing (Beijing Agricultural College, Beijing 102206 China)
Effects of resistance induced by Benzothiadiazole(BTH) at different concentrations against Alternaira alternata f. mali (AAM) in apple were investigated. Upper branches of apple trees were inoculated with spores of AAM after applying BTH as a foliar spray and disease index was investigated. The inhibitory effects of BTH against AAM on potato dextrose agar were studied. The contents of Hydroxyproline-rich glycoprotein (HRGP) and lignin were measured with colorimetric method after BTH treated. The results showed that application of BTH at different concentrations on apple leaves had significant effect to restrain AAM. The effect of 150 mg/L was distinctly better than others, and it could reduce the disease index from 26.34 to 16.87. In addition, the induced resistance would last more than 15 d after treated with 150 mg/L BTH; while conidiophores germination and mycelia growth weren’t restricted by BTH itself. The accumulation of HRGP and the deposition of lignin were measured after BTH treatment.