Reason - Outstanding control of Onion Downy Mildew and Early & Late Blight in Potatoes.

Reason is a locally systemic (translaminar) foliar fungicide, exhibiting strong protectant activity at key stages of the disease life cycle. It is temperature independent and acts rapidly against both direct and indirect disease germination.

Reason prevents disease spread (Anti-Sporulant), and exhibits translaminar movement to protect the underside of leaves, plus new and expanding leaves.

While Reason does exhibit curative properties under certain conditions, application is advised prior to the onset of disease.


  • Reason is fast acting rapidly killing disease spores, resulting in more consistent and effective disease prevention.
  • Translaminar movement - Reason penetrates and moves through the leaf tissue to protect the untreated side of the leaf, so preventing the progression of diseases, as well as pathogen sporulation on both sides of the leaf.
  • Strong anti-sporulant activity - Reason prevents sporulation, effectively stopping pathogens before they can spread to healthy leaf tissue and other plants within the field.
  • Proven performance - Practical use in Pukekohe has demonstrated Reason's efficacy in downy mildew.
  • Reason provides double performance in potatoes - equally effective in controlling early and late blight.
  • Reason is temperature independent, so is equally effective on direct and indirect germination of late blight sporangia.
Please download product label for full usage guidelines.

Using Reason on Onions

Disease: Downy mildew

Dose: 300 ml/ha

Using Reason on Potatoes

Disease: Early blight and Late blight

Dose: 300 ml/ha