5 July 2001
Resistant take-all fears ‘unfounded’
By FARMERS WEEKLY staff
SUGGESTIONS that some strains of take-all are resistant to silthiofam overstate the situation, says a co-author of the research paper behind the rumours.
The seed treatment from Monsanto was launched recently as Latitude, but doubts have already been cast over its effectiveness.
Isolates of the disease which are less susceptible to the fungicide have been identified, says Derek Holloman, formerly of IACR-Long Ashton.
But he maintains the effect and distribution of these strains is not known.
Even where a field was found to contain these isolates, the fungicide still gave normal responses and a build up in their number is unlikely, he says.
“Obviously there is a risk [of resistance to silthiofam], but the risk is no different from that with fluquinconazole.
“Fluquinconazole has the disadvantage of being a dmi fungicide which adds to the risk of resistance to dmi fungicides in foliar pathogens,” he says.