Development of white rot disease in onion transplants in Canterbury

Abstract

White rot disease was monitored in onions grown from transplants in two field sites in Canterbury and compared with disease development in direct seeded crops Onion seedlings cv Pukekohe Long Keeper (May and Ryan) were grown in seedling trays (25 ml volume) in the glasshouse for 12 weeks and transplanted to the field in August 1999 At both sites onset of disease occurred earlier in onion transplants and was more severe at all assessment times with 6070 disease recorded at harvest compared to 110 for direct seeded crops The benefits of an earlier harvest date for transplanted onions (January compared to March) was outweighed by the higher disease levels