Screening experiments for the effective fungicides of black rot disease of Gonggan(Alternaria citri)

[Aims]This paper aims to screen out the effective fungicides for controlling black rot disease of Gonggan(Alternaria citri).[Methods] The EC50 and EC95(mg a.i./L) of 15 different kinds of fungicides,such as ifenoconazole,pyraclostrobin,were tested with the both methods of the growth rate and spore emergence,meanwhile,the field control of five kinds of fungicides,such as flusilazole,were conducted.[Results] Sorting by EC95,the effect on inhibition of mycelial growth and spore germination from high to low: flusilazole,pyraclostrobin+prochloraz,pyraclostrobin,difenoconazole,prochloraz,mancozeb,propineb.The field trial results showed that the following fungicides have good effect: flusilazole 10% WP 1 g/L,difenoconazole+prochloraz 25% WP 1 g/L,chlorothalonil+carbendazim+mancozeb 50% WP 1.67 g/L and mancozeb+cymoxanil 72% WP 1.25 g/L,while flusilazole 10% EW 1 g/L with poor control efficiency.[Conclusions] The control effect is better of the fungicides whose formulations can resist rain erosion.