Trichoderma harzianum as fungicide and symbiont: is it safe for human and animals?

Trichoderma species are considered as biological control agents against numerous phytopathogenic fungi. They are also helpful for plants as plant symbiont. This study aimed to identify harmful effects of Trichoderma in laboratory animals. In the first step, inhalation toxicity was studied. Six rats as control received a spray of bio-formulation without spores. Ten rats as treatment A received    1.00 × 10⁶ colony-forming unit (CFU) of Trichoderma spores and ten rats as treatment B received 1.00 × 10⁷ CFU per test of Trichoderma spores. The harmful effects of Trichoderma were obvious especially in the lungs, liver and kidney, and some blood parameters were abnormal. In the second step, we studied acute oral toxicity by gavage. Four rats as control received bio-formulation without spores. Six rats as treatment A received 1.00 × 10⁶ CFU per test of Trichoderma spores. Six rats as treatment B received 1.00 × 10⁷ CFU per test of Trichoderma spores. The harmful effects of Trichoderma were noticeable more in the liver and kidney tissues. For dermal toxicity study, two rabbits as control received bio-formulation without spores by rubbing on the surface of the skin. Treatment groups A and B received 1.00 × 10⁶ and 1.00 × 10⁷ CFU per test of Trichoderma spores, respectively (four rabbits for each group). The liver and kidney and some blood parameters were abnormal. Trichoderma has some harmful effects on tissues and organs and although it is a natural product, it should be used under cautions.