Field-applied fungicides and postharvest treatments to control asparagus diseases posing biosecurity threats to New Zealand

Abstract

Collaborative research between New Zealand and Australia has investigated field-applied fungicides and postharvest treatments for control of asparagus rust (caused by Puccinia asparagi) and phomopsis stem blight of asparagus (caused by Phomopsis asparagi) in Queensland. In a 2004 field trial, the fungicides difenoconazole and propiconazole reduced the incidence of asparagus rust. In a 2005 field trial, four fungicides (carbendazim, chlorothalonil, iprodione and propiconazole) reduced the severity of phomopsis stem blight. Postharvest disinfection with sodium hypochlorite or with calcium hypochlorite at 150 ppm was highly effective at reducing Pu. asparagi and Ph. asparagi spore germination on water agar. Integrated disease management based on field and postharvest methods are suggested to reduce the risk of importation of the diseases to New Zealand. Similar methods could be used for controlling these diseases if they establish.