Grower Support Note: August 2017

Myclobutanil is an effective component in some pesticide sprays. That is, it kills fungi such as powderymildew and budrot. You find Myclobutanil in sprays such as “ Eagle 20 EW “. This fungicide belongs to the family of triazoles.

Some countries are contemplating a complete ban on Myclobutanil, because of concerns in the medical profession with regards to triazole resistant Aspergillus. Even so, Eagle 20 EW and similar products are applied frequently in conventional agriculture such as the farming of grapes.

When Myclobutanil is applied to tobacco or to marijuana, very serious health problems do occur: Myclobutanil releases highly toxic gases if heated past its boiling point of 205°C (400°F)  Butane lighters, such as those used to ignite marijuana for consumption, produce temperatures in excess of 450°C. These toxic gases include hydrogen chloride, hydrogen cyanide, and nitrogen oxide. This is why Eagle 20 EW is strictly forbidden by law on those crops in most countries.

However, because of the fact that Eagle 20 EW is an approved fungicide in certain other ag crops, it is relatively easily available to marijuana growers. Some growers of cannabis, large and small, have been known to spray their plants with this dangerous fungicide.

Similar concerns about this and other pesticides, have convinced thousands of sincere US based growers to revert to non-chemical crop protection technologies, such as for example germicidal UV against powdery mildew and Botrytis.

If you are a consumer:

Please ask your supplier for proof that the product is free of Myclobutanil. 

If you are a grower:

Please do not spray any product containing Myclobutanil on a crop that is to be smoked or of which the oil is to be extracted. Doing so is dangerous and against the law.


Arne Aiking