Antifungal activity of camptothecin on Rhizoctonia solani,Sphaerotheca fuliginea and Pseudoperonospora cubensis

Effectiveness of a naturally derived fungicide against Rhizoctonia solani,Sphaerotheca fuliginea and Pseudoperonospora cubensis was studied under greenhouse and field condition.In greenhouse,the cucumber(Cucumis sativus) seedlings,inoculated with the three fungi respectively,were planted in pot in the condition of 26 -28 ℃,95% relative humidity,12-hour photophase and 12-hour scotophase after 16 hours illumination.The seedlings were spraying camptothecin in concentrations of with three replications.In the field,the cucumber seedlings inoculated with P.cubensis were spraying with 5,10,20,40 mg·L-1 camptothecin,600 mg·L-1 flumorph-mancozeb and water(the control) by three replications.The results showed that the product exhibited strong antifungal activity on the three plant pathogens,the ρlc50 and ρlc90 values were 41.964 mg·L -1,40.495 mg·L -1,27.489 mg·L -1 and 756.776 mg·L -1,247.026 mg·L -1,341.818 mg·L-1 respectively.Field test of camptothecin against P.cubensis also showed that camptothecin had high inhibition effects on the pathogen,and the ρlc50 and ρlc90 values were 11.221 mg·L-1 and 69.128 mg·L-1 respectively.[Ch,2 tab.13 ref.]