against fungi, bacteria and insects

The antibiotic activity of 70 isolates belonging to the genera Aspergillus, Penicillium, Fusarium, Alternaria and Trichoderma was tested as preliminary screening. The highest activity was obtained with three Penicillium oxalicum iso-lates, one Penicillium decumbens isolate and the Trichoderma harzianum isola-te. After that, we chose these five isolates in order to carry out other studies with bacteria, fungi and insects. Extracts from these isolates were obtained. The extracts were tested for antibiotic activity with positive results, which implies that metabolite production is involved in this antagonistic effect. The highest activity was shown by T. harzianum and P. oxalicum extracts, but there was high variabi-lity among P. oxalicum isolates. Bactericidal and fungicidal activity, Secondary metabolites, Penicillium oxalicum, Penicillium decumbens, Trichoderma harzianum Actividad antagonista de Penicillium oxalicum Corri