Induced Disease-resistance in Mango Fruit by Pretharvest Benzothiadiazole (BTH) Spraying

The effects of pretharvest spraying with 1 mg/L,50 mg/L,100 mg/L benzothiadiazole(BTH) on the disease resistance induction of mango(Mangifera indica L.cv.Tainong No.1) fruits were investigated.The results indicated that,on the fruits treated with 100 mg/L BTH,the disease incidence of mango fruits at harvest,the disease index of non-inoculated mango fruits and the lesion diameter of mango fruits inoculated with C.gloeosporioides after harvest was 52.60%,54.30% and 7.06% lower than that on the controlled fruits,respectively.Meanwhile,the activities of defense enzymes,including phenylalanine ammonia-lyase(PAL),peroxidase(POD) and β-1,3 glucanase(GLU) in the fruits were all enhanced by the BTH treatment during storage.In addition,the catalase(CAT) activity in the fruit was inhibited,whereas the level of hydrogen peroxide(H2O2) was increased by the BTH treatment during 0 to 6 days after storage.