In this study, five new recently described Monosporascus species, M. brasiliensis, M. caatinguensis, M. mossoroensis, M. nordestinus, and M. semiaridus, which were found on weeds collected from cucurbit cultivation fields in northeastern Brazil, are characterized regarding mycelial growth at different pH levels and salinity (NaCl) concentrations, their pathogenicity to selected cucurbit species, and their sensitivity to fungicides with different modes of action. Our results reveal great variability among the representative isolates of each Monosporascus spp. All of them showed a wide range of tolerance to different pH levels, and NaCl significantly reduced their in vitro mycelial growth, although no concentration was able to inhibit them completely. In pathogenicity tests, all seedlings of cucurbits evaluated, melon, watermelon, cucumber, and pumpkin, were susceptible to the five Monosporascus spp. in greenhouse experiments using artificial inoculation of roots. Moreover, all Monosporascus spp. were highly susceptible to the fungicides fludioxonil and fluazinam. Our findings provide relevant information about the response of these new Monosporascus spp. to environmental factors, plant genotypes and fungicides.

Biological control employs beneficial microorganisms to suppress phytopathogens and mitigate the incidence of associated plant diseases. This study investigated the in vitro development and survival of Trichoderma spp. isolates derived from commercial formulations under different temperatures, pH levels, and sodium chloride (NaCl) concentrations and with synthetic fungicides with distinct modes of action. Three isolates were analyzed: URM-5911 and TRA-0048 (T. asperellum) and TRL-0102 (T. longibrachiatum). The results revealed substantial variability among the isolates, with the optimal mycelial growth temperatures ranging from 24.56 to 29.42 °C. All the isolates exhibited broad tolerance to the tested pH (5–9) and salinity levels (250–1000 mM), with TRL-0102 demonstrating the highest salt resistance. The fungicide treatments negatively affected mycelial growth across all the isolates, with Azoxystrobin + Difenoconazole and Boscalid causing growth reductions of up to 50%. Notably, Boscalid enhanced conidial production more compared to the control (126.0% for URM-5911, 13.7% for TRA-0048, and 148.5% for TRL-0102) and decreased the percentage of inactive conidia to less than 10% in all the isolates. These results provide strategic information for the application of Trichoderma spp. in agricultural systems, supporting the selection of more adapted and suitable isolates for integrated disease management programs.

-With the recent discovery of five new species of the Monosporascus genus, a fungal genus involved in "Monosporascus root rot and vine decline," pathogenicity studies have become important to understand the impact of these new species on cultivated plants, mainly on plant species used as an alternative for crop rotation. This study aimed to evaluate the pathogenicity of Monosporascus spp. in non-cucurbitaceous cultures. The tests were carried out in duplicate in a greenhouse in a completely randomized design, with the treatments: One isolate of each species of Monosporascus (M. brasiliensis, M. caatinguensis, M. cannonballus, M. mossoroensis, M. nordestinus, and M. semiaridus) and the absolute control, and five cultures (cowpea, jack bean, corn, sorghum, and bell pepper). Seeds of these cultures were sown in pots containing soil + Tropstrate HT (R) (ratio 2:1, v / v), previously inoculated with wheat seeds colonized with the species ofMonosporascus. After 50 days of sowing, plants were evaluated for incidence, disease severity, length of shoot and roots, fresh and dry weight of shoots and roots. All inoculated Monosporascus species were able to induce damage in cowpea and bell pepper cultures, with M. cannonballus being the most aggressive. Corn, jack beans, and sorghum presented few or no symptoms of the disease and may be indicated as alternative cultures to be used in crop rotation with cucurbits. Studies with a greater number of isolates and cultivars for each culture tested in this study should be carried out to strengthen the data obtained.