Effect of Propyl Dihydrojasmonate on Tobacco Resistance to Black Shank

The resistance of tobacco to black shank by treatment with propyl dihydrojasmonate (PDJ) was studied. The results indicated that PDJ had no suppression on the myceliar growth, sporangium produce,swarm spore release and germination. Foliar application with PDJ significantly reduced the disease severity of black shank. The optimal concentration of PDJ treatment for inducing resistance to black shank was at 100 mg/L. The proper time of treatment was at the third day earlier than inoculation with Phytophthora parasitica Var. nicotianae, and the induced resistance could last 15 d or more. Moreover, the disease severity of the upper untreated leaves was markedly reduced after the third leaf was treated with 100 mg/L PDJ. All the results indicated that PDJ significantly induced resistance of tobacco to black shank.