Grower Reference
Fungicides & Mycorrhizae
Not all fungicides are compatible with mycorrhizal inoculants. Use this chart to identify which products are safe to use, which to avoid, and which need more data.
Applying an incompatible fungicide at or near the time of mycorrhizal inoculation can reduce or eliminate colonization. The chart below - sourced from Mycorrhizal Applications, Inc. - covers common horticulture and turf fungicides and their effects on both endo and ecto mycorrhizal fungi.
Fungicide Compatibility Chart for Mycorrhizal Inoculants
OK to use
Avoid use
Insufficient data
| Trade Name | Active Ingredient | Endomycorrhizae | Ectomycorrhizae | ||||
|---|---|---|---|---|---|---|---|
| OK | Avoid | Insuf. Data | OK | Avoid | Insuf. Data | ||
| 3336 | Thiophanate-methyl | OK | ? | ||||
| Aliette | Fosetyl-AL | OK | OK | ||||
| Banner MAXX II | Propiconazole | Avoid | ? | ||||
| Banol | Propamocarb hydrochloride | OK | ? | ||||
| Banrot | Etridiazole + Thiophanate-methyl | ? | Avoid | ||||
| Bayleton | Triadimefon | Avoid | ? | ||||
| Captan | Captan | Avoid | No effect at low rate, tends to suppress at high rate. | ||||
| Chipco 26019 | Iprodione | OK | ? | ||||
| Daconil | Chlorothalonil | OK | No effect at low rate, tends to suppress at high rate. | ||||
| Dithane | Mancozeb | OK | ? | ||||
| Dorado | Propiconazole | Avoid | ? | ||||
| Eagle 20EW | Myclobutanil | OK | ? | ||||
| Fore | Mancozeb | OK | Avoid | ||||
| Fungo | Thiophanate-methyl | OK | ? | ||||
| Heritage | Azoxystrobin | OK | OK | ||||
| Lesan | Fenaminosulf | ? | Avoid | ||||
| Phaltan | Folpet | Avoid | Avoid | ||||
| Prodigy Signature | Fosetyl-AL | OK | OK | ||||
| Proplant | Propamocarb | OK | ? | ||||
| Rally | Myclobutanil | OK | ? | ||||
| Rubigan | Fenarimol | Avoid | ? | ||||
| Senator WSB | Thiophanate-methyl | OK | ? | ||||
| Sentinel | Cyproconazole | OK | ? | ||||
| Signature | Fosetyl-AL | OK | OK | ||||
| Strike | Triadimefon | Avoid | ? | ||||
| Subdue Maxx | Mefenoxam | OK | OK | ||||
| Systec 1998 | Thiophanate-methyl | OK | ? | ||||
| Systhane | Myclobutanil | OK | ? | ||||
| Terraclor | Pentachloronitrobenzene (PCNB) | No effect at low rate, tends to suppress at high rate. | Avoid | ||||
| Terraneb SP | Chloroneb | No effect at low rate, tends to suppress at high rate. | Avoid | ||||
| Terrazole | Etridiazole | ? | Avoid | ||||
| Teremec SP | Chloroneb | No effect at low rate, tends to suppress at high rate. | Avoid | ||||
| Tersan 1991 | Benomyl | Avoid | No effect at low rate, tends to suppress at high rate. | ||||
| Tersan 75 | Thiram | OK | Avoid | ||||
| Turfcide | Pentachloronitrobenzene (PCNB) | No effect at low rate, tends to suppress at high rate. | Avoid | ||||
| Ziram | Zinc dimethyldithiocarbamate | Avoid | Avoid | ||||
General Observations
- The longer you wait to apply any fungicide after mycorrhizal inoculation, the better for mycorrhizal fungi development.
- Most foliar sprays of any fungicide (except systemic products such as Bayleton) have little effect on mycorrhizal fungi.
- This chart covers horticulture and turf applications. Source: Mycorrhizal Applications, Inc. (updated May 2017).