After four years of field trials in Pukekohe to collect supporting data, Intuity Fungicide from Nufarm was approved in May for use against white rot in New Zealand onion crops, and is available in-store now.

Nufarm technical expert Alan Cliffe says Intuity’s launch has already been welcomed by growers looking to mitigate their on-going risk of fungicide resistance and protect existing chemistry in their spray programmes.

The active ingredient in Intuity – mandestrobin – was developed by Sumitomo of Japan, where it was first launched just two years ago.

Mandestrobin is a proprietary strobulurin fungicide which is highly active against the organism that causes white rot, Sclerotium cepivorum, as well as other fungal species.

Just as importantly, it is the only Group 11 fungicide NZ onion growers can now use against white rot that does not come formulated with another active or mode of action (MOA).

This makes it very valuable for growers who need to rotate between three different MOA groups throughout the season as part of recommended best practice for managing fungicide resistance in white rot.

Group 3 comprises DMI fungicides, Group 7 the SDHI’s and Group 11 the Qol’s. NZ Onions advises growers to use no more than three applications of a fungicide from any particular group during the same season, while most product labels recommend no more than two applications of the particular product.

“Where it can get complicated is where growers are using fungicides with multiple actives and multiple MOAs,” Alan Cliffe says.

“In those situations, what might be thought of as ‘one’ application in the field effectively ends up counting as two, because you’re putting on two MOAs in a single spray.”

As a stand-alone Group 11 formulation, Intuity Fungicide will help simplify spray rotation planning.

An added advantage is that it has very good activity against onion downy mildew Peronospora destructor, so onion white rot applications contribute to the spray programme against this disease.

Technically, it has the additional benefits of being an SC liquid formulation, which makes it easy to measure, pour and mix. With systemic, translaminar, protectant and anti-sporulant properties, it has activity against most stages of white rot growth. Toxicity is low (9.1B) and crop safety is excellent.

Alan Cliffe says Intuity’s unique disease spectrum, which also includes Monolinia and botrytis, means onions are likely to be the first of a series of vegetable crop claims for the advanced new fungicide.

For more detail contact your Nufarm territory manager.