Systemic acquired resistance as a strategy for postharvest disease management on rockmelon (Cucumis melo var. Reticulatus)
Nguyen P.T.; McConchie R.M.; McDonald K.L.; Anwaral B. and Morris S.C.
5th International Postharvest Symposium . Volume of Abstract . Verona, Italy 6-11 June 2004, p.102
2004
บทคัดย่อ
In glasshouse experiments, preharvest applications of the SAR activator Bion ® (acibenzola-S-methyl or BTH-Benzothiadazole) on rockmelon plants at different physiological growth stages, led to a significant increase in leaf chitinase activity immediately after application. Chitinase activity peaked approximately 7 days after each application before declining back to control levels. BTH sprayed plants were protected against powdery mildew (Sphaerotheca fuliginea) infection, suggesting that chitinase played an important role in disease resistance.
In a field experiment, rockmelon plants were treated with BTH at 50 ppm (a.i.) at male flowering, 2 weeks after male flowering and 5 weeks after male flowering. The pattern of chitinase induction was very similar to that of the glasshouse experiments, except in the last application at 5 weeks after male flowering, in which no significant induction of chitinase was measured within 7 days. The preharvest application of BTH on rockmelon plants protected rockmelon fruit from postharvest disease infection of Fusarium equiseti, Alternaria alternata and Colletotrichum spp. A synergistic effect was observed between SAR and the dipping fungicide guazatine in controlling rockmelon postharvest diseases, providing better disease control than either treatment alone. Preharvest application of BTH had no phytotoxic effects on the growth of plants as measured by leaf area, fruit yield and sugar content of treated fruits. The results indicate that preharvest applications of BTH to rockmelon plants has potential for integration into a program of postharvest disease control of fruit.