The latest independent trials have shown promising but mixed results for biological fungicide product Serenade for controlling Rhizoctonia solani (blackleg) in potato crops.
The product, which contains the bacteria Bacillus subtilis, has an off-label approval for use in potatoes to control a range of disease-causing pathogens, applied either in-furrow at planting or as a seed treatment.
After Bayer CropScience acquired US biopesticide company AgraQuest in 2012, it gained the rights to market Serenade and in 2013 commissioned various trials to learn more about the product and how it is used.
Scotland’s Rural College (SRUC) potato expert Stuart Wale carried out one of the experiments and told Crops that although results were variable, it is still a useful product in an integrated disease control approach.
Dr Wale explains the bacteria contained in Serenade are very active on the soil-borne pathogen Rhizoctonia solani, which causes black scurf and stem canker.
He also suspects that it has good activity against a wider range of pathogens but, so far, trials in the UK have been limited to validate his suspicion.
“The difficulty with these biological controls is that their efficacy can be seriously influenced by the conditions at application and it has to compete with all the other soil biota,” he adds.