Storage case clear for imazalil users

13 October 2000

Storage case clear for imazalil users

DUTCH potato growers doubts about the efficacy of imazalil as an in-store silver scurf treatment have been shown to be unfounded by recent research at the PAV institute in Lelystad.

But the research has raised questions about imazalils efficacy as a seed treatment against the disease and the way it is applied on farm, says PAVs Daniel Bos.

"We think the big problem is the way they are spraying the tubers. If they are sprayed on a conveyor, only the top is covered.

"Roller-tables are much better, but they have a smaller capacity. They cant do the 40-60t/hr that is needed."

Increase doubled

In the work, where tubers were treated effectively, silver scurf only increased from 6% of one side of the tuber affected before storage, to 8% at the end of the storage period. However, on untreated tubers, the increase was more than double that, resulting in 13% silver scurf.

Loading stores so that boxes are tight against ventilation walls could help reduce the spread, says Mr Bos. That would allow growers to force ventilation through the boxes to dry tubers more quickly and prevent condensation.

"But there are many practical problems with stacking against the walls. Boxes have to be perfectly stacked or you will lose a lot of the ventilation capacity."

Although imazalil is effective on silver scurf in store, preliminary findings from work with five pre-planting fungicide treatments suggest that it is far from the best in the field. "It didnt really work," says Mr Bos. &#42

Potato storage research has raised questions about the way imazalil is applied, says Daniel Bos of the Dutch research organisation PAV.

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