Biorational and conventional insecticides efficacy to control thrips (Frankliniella occidentalis Perg.) on strawberries (Fragaria x ananassa Duch.) at Morelos state, Mexico: Spanish

Strawberry cultivation presents multiple phytosanitary limitations among which the “western flower thrips” stands out. Adults and nymphs of F. occidentalis produce severe damage to flowers and fruits, reducing the yield and quality of the product. In Mexico, thrips control is based on the use of synthetic chemical insecticides. The objective of this research was to evaluate the insecticidal effectiveness of biorational and conventional products as control alternatives and their phytotoxic effects in strawberry cultivation. The study was carried out in strawberry cv. Camino Real in flowering stage - fruiting established in open ground. A completely randomized design with seven treatments and four replications was used. Significant differences between treatments could be identified; Imidacloprid + Lambda Cyhalothrin and Bifenthrin caused the highest mortality of thrips with an efficiency of 92 and 93% respectively. Spinosad obtained good results, ranking as the second best option with 90% control efficiencies; neem extract stood out as an excellent biorational pest management alternative with 77% control efficacy in the last evaluation. No phytotoxic effects were observed from any of the treatments on the crop.Objective: To evaluate the insecticidal effectiveness of biorational and conventional products as alternatives to control thrips and their phytotoxic effects in strawberry cultivation. Design / methodology / approach: The research was carried out in strawberry cv. Camino Real during its flowering stage - fruiting established in open ground; A completely randomized experimental design with seven treatments and four replications was used. The treatments evaluated were: T1: neem oil extract, T2: paraffin oil, T3: garlic extract + hot chili pepper + cinnamon, T4: spinosad, T5: imidacloprid + lambda cyhalothrin, T6: bifenthrin, and T7: control. Applications were made weekly and the mortality evaluation was carried out by counting the number of live thrips per flower. With the obtained data, an analysis of variances and a mean comparison test (Tukey, p ≤ 0.05) were performed. Results: Significant differences between treatments could be identified (p ≤ 0.05); imidacloprid + lambda cyhalothrin and bifenthrin caused the highest mortality of thrips with 92 and 93 % efficacy, respectively. Spinosad obtained good results, ranking as the second-best option with 90 % control efficiencies; neem extract stood out as an excellent biorational pest management alternative with 77 % control efficacy in its last evaluation. No phytotoxic effects were observed from any of the treatments on the crop. Limitations on study / implications: It is important to continue the study in the laboratory to obtain the LD50 and LD90 of the management alternatives, as well as an MRL analysis of the molecules used. Findings / conclusions: The proposed protocol evidenced the efficacy of biorational and ecological thrips control treatments in intensive horticultural systems

Antagonismo enzimático de Trichoderma spp. sobre Fusarium oxysporum y Phytophthora parasitica en Hibiscus sabdariffa L.

Mexico is the seventh largest producer of jamaica (Hibiscus sabdariffa), and Guerrero State agglomerates more than 70 % of the national production. The crop presents important phytosanitary limitations, highlights the "black leg" associated with a complex of pathogens (Fusarium oxysporum and Phytophthora parasitica). Losses up to 100 % are reported in areas without phytosanitary management. Due to the nature of the consumption of the final product, it is necessary to implement ecological strategies to manage the disease. The objective of the study was to quantify the chitinases and glucanases activity of Trichoderma spp. isolates, and to evaluate their inhibitory effect in vitro on F. oxysporum and P. parasitica. Strains Ta10, Ta11, Ta6 and Ta9 of T. asperellum and Ti14 of T. inhamatum from soils cultivated with jamaica and high incidence of the pathogens were evaluated. The levels of chitinases and glucanases produced in all Trichoderma spp. were significant (P0,05), and it was found that Ta9 had the highest specific chitinase activity, and Ti14 the highest for glucanase. All the filtrates from the different isolates of Trichoderma spp. generated a substantial inhibition of mycelial growth of F. oxysporum and P. parasitica. Consistently, the strain Ta9 produced inhibition percentages greater than 90 % in both tests. A significant correlation was detected between the enzymatic activity and the inhibition of the growth of the Trichoderma spp. isolates on pathogensMéxico es el séptimo productor de jamaica (Hibiscus sabdariffa), y el estado de Guerrero concentra más del 70 % de la producción nacional. El cultivo presenta limitantes fitosanitarias importantes, destacando la “pata prieta” asociada a un complejo de patógenos (Fusarium oxysporum y Phytophthora parasitica), con pérdidas de hasta 100 % en áreas sin manejo fitosanitario. Debido a la naturaleza del consumo del producto final, es necesaria la implementación de estrategias ecológicas de manejo de la enfermedad. El objetivo del estudio fue cuantificar la actividad de quitinasas y glucanasas de aislados Trichoderma spp., y evaluar su efecto inhibitorio in vitro sobre F. oxysporum y P. parasitica. Se evaluaron las cepas Ta10, Ta11, Ta6 y Ta9 de T. asperellum y Ti14 de T. inhamatum provenientes de suelos cultivados con jamaica y alta incidencia de los patógenos. Los niveles de quitinasas y glucanasas en todos los aislados de Trichoderma spp. fueron significativos (P0,05); la cepa Ta9 mostró la mayor actividad específica de quitinasas, y la cepa Ti14 la mayor de glucanasas. Todos los filtrados provenientes de los diferentes aislados de Trichoderma spp. generaron una inhibición sustancial del crecimiento micelial de F. oxysporum y P. parasitica. De manera consistente, la cepa Ta9 alcanzó porcentajes de inhibición mayores al 90 % en ambos ensayos. Se detectó correlación significativa entre la actividad enzimática y la inhibición del crecimiento de los aislados de Trichoderma spp. sobre los agentes patógenos

MORPHOLOGICAL DIVERSITY OF APAXTLECO CHILLI PEPPER NATIVE OF GUERRERO, MEXICO

Background. Mexico has a great diversity of chili peppers, especially in C. annuum L., which includes local morphotypes that have been little studied. Apaxtleco chili pepper is only found in Guerrero State, Mexico, and it is important in Apaxtla region due to economic resources it generates, and because it is used in preparation of typical mole in this region; however, its morphological diversity has not been described and this visualizes the state of this plant genetic resource to define use and conservation strategies. Objective. To analyze and describe morphological diversity of a group of Apaxtleco chili pepper populations, identify characteristics that most support its diversity and establish similarity relationship between the populations studied. Methodology. Twenty-four populations of apaxtleco chili pepper collected from Apaxtla de Castrejón, Guerrero were evaluated under randomized complete block experimental design, with four replications. The evaluation was carried out under greenhouse conditions at Tuxpan Unit of Autonomous University of Guerrero. Sowing was carried out in July 2020 in polyethylene pots with 16 L capacity. Fifty-nine morphological variables from IPGRI descriptors for Capsicum were recorded, and variance, discriminant, principal components (CP) and conglomerated analysis were performed by SAS V9.3 software. Results. Statistical significant differences were found in 72.9 % of variables registered and seventeen were selected by its contribution to variation according discriminant analysis, which were mostly fruits characteristics. In CP, with the first six, 76 % of total morphological variation was explained; length fruit and pedicel, width seed, weight fruit per plant, color of fruit at intermediate stage, number fruits per plant, width fruit, fruit and seed texture, filament color, number seeds per fruit and shape fruit appendage had greater contribution to total morphological diversity and were useful to differentiate populations under study. As well, four groups of apaxtleco chili pepper with different fruit, vegetative and flower characteristics were identified, however, it was possible to group them by shape and texture of fruits. Implications. Contribute to description of diversity of local populations of apaxtleco chili, native to Guerrero, Mexico, and that allows the establishment of use and conservation mechanisms for food security. Conclusion. Morphological diversity of native apaxtleco chili of Guerrero is presented mainly in fruit characteristics and lesser degree in vegetative and seed traits, which were useful to explain greater total variation in this local chili. The shape and texture fruits were important characteristics in grouping