Fungicide Activity Made Simple

The terms used to classify fungicide activity on the various stages of fungal development can be misunderstood (ie. curative activity will ‘cure’ a well-established infection). Below are definitions of the 3 categories of activity, referencing work from Australia, which hopefully helps provide some clarity and may be of value as efforts are turned towards crop planning for the upcoming season. 

When it comes to multiple modes of action products, like MAXENTIS^® and SORADUO^™, these products exhibit attributes from multiple categories that show curative, protective, and eradicative properties.

Protectant or Preventative Activity: 

Fungicides that are meant to stay on the surface; they do not enter into the vegetative tissue. Fungal spores which land on a treated plant encounter a protective barrier which stops germination and ensuing infections. These products are most effective on diseases which grow and develop on the surface of the plant. FOLPAN 80 WDG and CAPTAN 80 WSP are examples of true protectant fungicides.

Curative Activity: 

Also known as penetrant activity, fungicides that enter the tissue of the plant and work to stop or reduce fungal growth. These products only have activity on the early stages of fungal colonization so should be applied prior to, or within a few days, of infection. BUMPER^® 432 EC is an example of a curative product.

Eradicant Activity: 

These are fungicides that act on the later stages of colonization, stopping or reducing disease development, and in some instances can help suppress spore production. Eradicant products are generally able to move within the plant, but are most useful for localized infections; they will not eradicate an infection which has gone systemic. As such, best used in the early stages of a disease’s life cycle. ORIUS^® 430 SC is an example of a fungicide with eradicant activity.