Macrobrachium americanum is a large prawn living in rivers and coastal water bodies of tropical and subtropical ecosystems of the Pacific side of the Americas. Water temperature and salinity are the main physicochemical variables determining its distribution. Temperature also influences its metabolic rate, which determines growth rate and reproduction. Because of this, preferred temperature, critical thermal maximum (CTMax), and O2 consumption rates at four temperatures (20, 24, 28, and 32°C) were tested from wild prawns in laboratory assays. Those temperatures correspond to the annual temperature fluctuations at the sampling site. The final preferred temperature of this species is close to 26.4°C. The acclimatization temperature has an almost linear effect on the CTMax (R2 = 0.987, P < 0.05), and the oxygen consumption routine rates increased as the acclimation temperature increased from 20 to 32°C.

White mold (Sclerotinia sclerotiorum) reduces potato yield and quality in Sinaloa, Mexico. This study first evaluated the in vitro efficacy of Trichoderma azevedoi, T. afroharzianum, T. asperellum and T. asperelloides in inhibiting S. sclerotiorum mycelial growth and sclerotia production. Field experiments then assessed a combination of these antagonists, their alternating application with synthetic fungicides, and a fungicide-alone treatment for disease control, sclerotia reduction and yield increase. In vitro, all four Trichoderma species significantly inhibited the pathogen, achieving 60.1–63.1% mycelial suppression in dual culture and 90.3–94.1% via volatile metabolites, with the latter also completely suppressing sclerotia formation. In the field, the Trichoderma combination significantly controlled white mold, reducing plant incidence and severity to 66.0 and 27.1% in 2021 and 55.6 and 18.8% in 2022, while lowering sclerotia production to 32.7 and 14.6 on ten plants, respectively. This control extended to tubers, where incidence and severity were reduced to 1.6% and 0.4% in 2021, and 1.3% and 0.3% in 2022. The alternating application of Trichoderma with synthetic fungicides proved statistically equivalent to the Trichoderma-alone treatment in disease control, while the fungicides-alone treatment was significantly less effective. Potato yield was highest in plots treated with the Trichoderma combination (46.0 and 52.9 t ha⁻¹ in 2021 and 2022, respectively). These results highlight the potential of using a mixture of these four Trichoderma species as a cornerstone of sustainable disease management in Sinaloa, offering effective control of potato white mold while significantly reducing dependence on synthetic fungicides.

Leucophyllum frutescens (Scrophulariaceae family), commonly known as Texas sage or cenizo, is an evergreen shrub native to southwestern United States and northern Mexico. This plant is commercially...

A strain isolated from potato common scab superficial lesions in El Fuerte Valley in northern Sinaloa, Mexico, was identified by 16S rRNA and morphological methods. Moreover, the effects of the crude extract of strain V2 was evaluated on radish and potato. The isolate was similar to Streptomyces acidiscabies in its morphological properties; however, the 16S rRNA gene sequence of strain V2 was neither 100% identical to this species nor to the streptomycetes previously reported in Sinaloa, Mexico. Strain V2 did not amplify any specific PCR products for genes nec1 and tomA, which have been found and reported in S. acidiscabies. Strain V2 produced a PCR product for the txtAB operon, which is related to the production of thaxtomin. In vitro assays using crude thaxtomin extract and a spore suspension of the organism caused necrotic symptoms on radish and potato, which were highly virulent in potato. This study reports that Streptomyces sp. V2 has a toxigenic region (TR) that is associated with the thaxtomin gene cluster. Se aisló una cepa de una lesión superficial de sarna común de la papa en un ejemplar procedente del Valle del Fuerte, en el norte de Sinaloa, México. La cepa fue identificada por secuenciación del gen 16S ARNr, y por sus características morfológicas. Los efectos del extracto crudo de dicha cepa, llamada V2, fue evaluado en papa y rábano. El aislado fue similar a Streptomyces acidiscabies en sus características morfológicas, pero la secuencia del gen 16S ARNr de la cepa V2 no fue 100% idéntica a la de dicha especie, ni tampoco a las de cepas identificadas dentro de este taxón previamente en Sinaloa, México. La cepa V2 no amplificó los productos específicos de PCR de los genes nec1 y tomA, los cuales sí se han reportado en S. acidiscabies. La cepa V2 amplificó el producto de PCR para del operón txtAB, relacionado con la producción de taxtomina. A través de ensayos in vitro usando un extracto crudo de taxtomina y una suspensión de esporas del organismo aislado se verificó la producción de síntomas necróticos en rábano y papa, con mayor virulencia en esta última especie. Este estudio indica que Streptomyces sp. V2 tiene una región toxigénica (TR) asociada con el cluster de genes de taxtomina.

Brown spot on the leaf sheath is an emerging disease of sweet corn (Zea mays L.) in Sinaloa, Mexico, with an unknown etiology. This study aimed to identify the causal agent of the disease and assess its pathogenicity on commercial sweet corn hybrids. Bacterial strains were isolated from symptomatic leaf sheaths collected from commercial fields. Identification was performed through biochemical profiling (API 50CHB/E), pathogenicity tests on alternative hosts (potato, onion, celery), and molecular analysis (16S rRNA and recA genes sequencing and phylogenetic reconstruction). Pathogenicity and virulence were confirmed by inoculating four sweet corn hybrids in a greenhouse. The strains were Gram-negative rods, identified as Burkholderia gladioli based on biochemical profiles and molecular data (99% 16S rRNA+ recA similarity; phylogenetic clustering within the B. gladioli clade). In greenhouse trials, the strains induced brown spot lesions on the leaf sheaths of all tested hybrids, replicating field symptoms fulfilling Koch’s postulates. This is the first report of B. gladioli as the causal agent of brown spot on the leaf sheath of sweet corn in Mexico. The pathogen’s broad host range highlights its potential as an emerging threat to horticultural crops in the region.

White mold (Sclerotinia sclerotiorum) affects potato production and quality in Sinaloa, Mexico. This study aimed to determine the in vitro efficacy of Trichoderma azevedoi, T. afroharzianum, T. asperellum and T. asperelloides in inhibiting the mycelial growth and sclerotia production of S. sclerotiorum. Field studies were also conducted to evaluate the effectiveness of a Trichoderma spp. combination in controlling the disease and reducing sclerotia production, as well as increasing crop yield in semi-commercial plots. In parallel, the alternating use of the antagonist combination with synthetic fungicides was assessed; an additional treatment involved using synthetic fungicides alone. The in vitro tests demonstrated the efficacy of all four Trichoderma species against the pathogen. The Trichoderma combination also significantly controlled white mold under field conditions. The alternating application of Trichoderma species with synthetic fungicides was similarly effective, while the fungicides-alone treatment was less effective than the two aforementioned treatments. The results highlight the potential of using a mixture of these four Trichoderma species to control potato white mold in Sinaloa, which could help reduce the reliance on synthetic fungicides for disease management.