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What is Rotstop C?

Rotstop C is a stump treatment used to prevent the introduction and spread of Heterobasidion Root Disease (HRD) in conifer plantations. A biological fungicide, Rotstop C contains spores of the naturally occurring wood decay fungus Phlebiopsis gigantea, which grows into the stump and prevents HRD from becoming established.

How Rotstop C Works

Rotstop C is a wettable powder that is applied as an aqueous mixture. Blue dye is added to the mixture to better observe treatment coverage. P. gigantea grows into the stump and penetrates deep into the infected root system, naturally out-competing H. irregulare and preventing it from becoming established or spreading. Rotstop C was developed for use with automated/mechanized harvesters or with manual spray systems and will provide the most effective protection when applied at the time of felling or soon after.

Related Pest & Pathogens

Rotstop C  Labels
Rotstop C

The product label contains directions and application rates.

Rotstop C Sds
Rotstop C

This Safety Data Sheet contains occupational safety and health data for this product.


Rotstop C is a stump treatment used to protect freshly cut stumps from Heterobasidion (also known as Fomes or Annosum) Root Disease (HRD). Rotstop C is a biological fungicide that contains spores of the naturally occurring wood decay fungus, Phlebiopsis gigantea. Rotstop C is a wettable powder that is applied as an aqueous mixture.

Rostop C is registered by the Environmental Protection Agency (EPA Registration Number: 64137-12) in the following states: Alabama, Florida, Georgia, Michigan, North Carolina, South Carolina, Virginia, and Wisconsin.

Rotstop C is registered in Canada by the Pest Management Regulatory Agency (PMRA) (registration NO. 31140).

Rotstop formulations have been proven to be very effective in protecting conifer plantations from HRD in Europe for over 30 years. Numerous field studies in Europe and North America and years of operational application have demonstrated very high efficacy (in some studies up to 90% effectiveness) of Phlebiopsis gigantea in preventing HRD.

Benefits of using Rotstop C include:

  • Incorporating Rotstop C into conifer plantation management can maximize productivity by preventing tree growth loss and mortality and provides assurance that conifer assets are protected from HRD.
  • According to peer-reviewed research, Phlebiopsis gigantea poses no risk to living trees or agricultural crops, making Rotstop C an ideal treatment option to help sustain forests for future generations.
  • Peer-reviewed research also confirms that Phlebiopsis gigantea naturally decomposes dead wood, aiding in the decay of freshly cut stumps. Other treatment options, such as borate products, act as a wood preservative, increasing the time it takes for a stump to naturally decompose.
  • Rotstop C is a low-cost control option, comparable to other stump treatments available

The following package sizes are available in the US:

  • 0.13oz package yields 1 US gallon
  • 0.67oz package yields 5 US gallons

The following package sizes are available in Canada:

  • 20 x 5 g wettable powder packages
  • 10 x 5 g wettable powder packages

Rotstop C is distributed by BioForest. Orders can be placed by contacting the Order Desk at or by phone at 1-888-236-7378.

Vigorous agitation is not needed. Rotstop C comes in pre-measured packages that, after being mixed with a small amount of water to form a slurry, are poured into volumes of water. Gentle mixing is sufficient to disperse the Phlebiopsis gigantea spores in the water. Refer to the product label for the Directions for Use.

Dye can be added to the mixture to observe treatment coverage. Blue dye can be purchased from BioForest.

During cold times of the year, if the temperature is expected to rise above 40°F (4°C) anytime during the two weeks after felling, Rotstop C should be applied if possible. Because Rotstop C is mixed with water, applying it in very cold weather may not be possible because the product might freeze in the lines of the spray system. However, under these conditions, adding propylene glycol (not ethylene glycol) to the mixture (up to 10%, e.g. 13 fluid oz. [500 mL] propylene glycol in 1 gallon [5 litres] of mix) can prevent freezing to 27°F (-3°C) without reducing the efficacy of Rotstop C, if used the same day.

It is recommended to apply Rotstop C immediately after felling to ensure Heterobasidion spores cannot infect freshly cut stumps.

Unopened packages can be stored up o 12 months in a cool (below 46°F/8°C), dry place and up to 18 months when frozen (0°F/-18°C). Packages taken from cool conditions and thawed to room temperature must be used within one month. Rotstop C contains living fungal spores and should not be exposed to temperatures above 100°F (38°C) in order to ensure maximum efficacy. Use open packages within 24 hours.

Effective Control of Heterobasidion Root Disease (HRD) with Rotstop C

RotStop C is a biological fungicide and is used as a stump treatment to protect freshly cut stumps from Heterobasidion Root Disease (HRD), a serious disease that affects red and white pine plantations.