Effective Inhibition Duration and Field Control Effectsof 16 Fungicides Against Neoscytalidium dimidiatum

【Objective】Fungicides with long effective inhibition duration and good field control effects against Neoscytalidium dimidiatum were screened to provide scientific basis for the control of the most destructive pitaya brown rot disease in pitaya production.【Method】By measuring the size and disappearing time of inhibition zone, the effective duration of 16 fungicides against N. dimidiatum mycelial growth were determined by agar diffusion method. And field control efficacy of fungicides with good effective inhibition or long duration were tested and compared.【Result】Six fungicides,including fludioxonil, propiconazole, prothioconazole, tebuconazole, flusilazole and iprodione, showed long effective inhibition duration, and the inhibition zone did not disappear after being cultured for 15 days. Three fungicides, including prochloraz, difenoconazole and myclobutanil, showed relatively long effective inhibition duration. Three fungicides, including carbendazim, probenazole and azoxystrobin, showed short effective inhibition duration. Four fungicides, including propineb, kasugamycin, chlorothalonil and epoxiconazole, showed extremely short effective inhibition duration. Field efficacy tests indicated that 5 fungicides, including tebuconazole, iprodione, lusilazole, prothiazolium and propiazole, showed good control effects on the tender stem of the pitaya. Except that procineazole at the active ingredient concentration of 500 mg/kg could inhibit the growth of tender stems of pitaya, the other 4 fungicides were safe for the growth of pitaya.【Conclusion】It is preferentially recommended to use systemic fungicides of tebuconazole, iprodione, lusilazole, prothiazolium and propiazole to control the pitaya brown rot disease with rotation, and application concentration of which should be appropriately increased while the pitaya orchard facing with high disease pressure.