Compatibility of the commercial biological control agents Trichoderma asperellum (ICC 012) and Trichoderma gamsii (ICC 080) with selected herbicides

• Published in: Journal of plant diseases and protection (2006) 2022-02, Vol.129 (1), p.85-92
• Main Authors: Celar, Franci Aco, Kos, Katarina
• Format: Article
• Language: English
• Subjects: Biomedical and Life Sciences; Life Sciences; Original Article; Plant Pathology; Plant Physiology; Plant Sciences
• ISSN: 1861-3829; 1861-3837
• DOI: 10.1007/s41348-021-00547-7

The in vitro effects on mycelial growth of the antagonistic fungi Trichoderma asperellum (ICC 012) and Trichoderma gamsii (ICC 080) were studied based on the active ingredients of 12 commonly used herbicides: amidosulfuron, dicamba, fluazifop-P-butyl, fluorochloridone, foramsulfuron, isoxaflutole, metribuzin, pendimethalin, prosulfocarb, pyridate, S-metolachlor and tembotrione. The fungal growth rates were evaluated at 20 °C and 25 °C using PDA plates that included 100%, 75%, 50%, 25%, 12.5%, 6.25% and 0% of the recommended herbicide application rates. These herbicides were classified into four categories based on inhibition of mycelial growth in the toxicity testing. Growth inhibition of Trichoderma spp. was seen for all of these herbicides at almost all doses and at both temperatures, although some major differences were seen. Lower herbicide concentrations in the agar also reduced the inhibitory effects, but generally not linearly. Temperature had no significant effects on the levels of inhibition of mycelial growth. Amidosulfuron, dicamba and isoxaflutole showed the least inhibition of mycelial growth of both Trichoderma spp., and the lowest doses with amidosulforone (6.25%, 12.5%) even significantly stimulated mycelial growth of both Trichoderma spp. Fluazifop-P-butyl, pyridate and tembotrione showed moderately harmful to harmful effects on mycelial growth, with 70% to 80% inhibition at the recommended herbicide application rates. Fluorochloridone, S-metolachlor, prosulfocarb, metribuzin and pendimethalin inhibited mycelial growth the most, in descending order of inhibition. At 50% to 100%, fluorochloridone, prosulfocarb and S-metolachlor had fungicidal effects. Fluorochloridone and prosulfocarb had significant inhibitory effects (> 75%) even at the lowest concentration of 6.25%. Of these herbicides tested, the least adverse effects were seen for amidosulfuron, dicamba and isoxaflutole, which are thus likely to be compatible with Trichoderma spp. in the field.