The prospection of bioherbicides has been an alternative to weed control, aiming at mitigating chemical risks to human, animal and environmental health due to extreme use of synthetic herbicides. In the present study, various fungi were isolated from plants with symptoms of fungal diseases for bioherbicide purposes against weeds (Urochloa plantaginea, Euphorbia heterophylla and Bidens pilosa). Fungi isolated were identified by molecular methods and enzymatic products obtained by fungi fermentation (cellulase, lipase, peroxidase, and amylase) were quantified. Bioherbicide selectivity study was performed on crops (soybean and corn), as well as on resistant weeds. Among the isolated fungi, Fusarium oxysporum, Fusarium ploriferatum, and Trichoderma koningiopsis presented bioherbicide potential. T. koningiopsis, in particular, presented the highest effect on Euphorbia heterophylla (popular name - Mexican fire plant), causing up to 60% of foliar damage, without presenting phytotoxicity against corn crop. New perspectives for weeds control and their use in corn crops were prospected, considering the bioherbicide selectivity described in this study.

This study aims to evaluate the production of compounds (fungal extract) from Trichoderma koningiopsis with herbicidal activity, as well as to analyze the effects of its application and acute toxicity using the microcrustacean Daphnia magna. Plackett & Burman Experimental Design (PB) was selected, followed by a triplicate fermentation with the best conditions after a Central Composite Rotatable Design (DCCR 23). The dependent variables (responses) evaluated were the enzymatic activities of amylases, cellulases, lipases and peroxidases, and the fungal biomass produced was also quantified. A statistical analysis was performed on the variables to verify their significance and evaluate the validity of the proposed model. Two different fungal extracts were used for evaluation of acute toxicity, and were also applied in the Euphorbia heterophylla plant to verify the effects of phytotoxicity. Thus, the results obtained for the acute toxicity tests were EC50-48h of 58,637.99 mg/L and 13,583.17 mg/L for the first and second extract, respectively. The first one showed yellowing of the leaves of the plant. The results showed that the produced compounds are promising alternatives for reducing the use of chemical herbicides, since the microorganism showed potential for the biological control of weeds.