Fruit Damage Patterns Caused by Ovipositing Females of Conotrachelus dimidiatus

We evaluated the damage patterns produced by females of the guava weevil Conotrachelus dimidiatus Champion, 1904 (Coleoptera: Curculionidae), according to the position of the damaged fruit in guava trees Psidium guajava L. in Calvillo, Aguascalientes, Mexico. The trees were subdivided in eight zones, and during one year the level of fruit lesions due to oviposition was registered. Results showed a higher level of damage in the upper and external zone of the trees (P≤.05). We found no significant differences in damage between the four cardinal points (P≥.05). During the year, the level of damage was recorded and was higher in the months of August and September (P≤.05) associated with rainfall (0.86, P=.06) and increase in temperature (0.84, P=.03). The most susceptible fruits were in the size range of 2.1–4.0 cm (polar diameter). The information from this study will be used to design and establish effective control strategies for the guava weevil, taking into account location of the most susceptible fruits, seasonality of the pest, and the abiotic factors

Características morfológicas y genéticas permiten la identificación de cultivares de ajo en las regiones Norte y Central de México

"The objective of this study was to compare the yield and genetic relationships between two Perla garlic selections, obtained by individual selection of cloves, and commercial varieties and cultivars adapted to diverse regions of Mexico (which did not have a selection process). Varieties with fewer cloves showed higher yields. Coreano and California produced 20 ton/ha (fresh weight) and Perla selections between 17-1.9 ton/ha (fresh weight). Six primers of the series OPB were tested for frenetic characterization and OPB-17 was selected. With the. amplified DIVA fragments, a binary matrix was generated; afterwards, a dissimilarity matrix and dendrogram were developed. High genetic diversity was found among all varieties, which were separated into two groups through differential analysis. Varieties of smaller yield were included in one group. The other group was constituted by the best production varieties with fewer cloves per plant (Perla, California, Coreano and Chino). Dissimilarity was found among Perla varieties. The selection method used to obtain plants with better yield characteristics can be applied to the genetic improvements of garlic.

Aprendizaje en línea durante COVID-19 con estudiantes de ingeniería de zonas rurales marginadas en México

COVID-19 has affected education worldwide, in Mexico. In this study, the impact of the extraordinary online modality because of the pandemic on the accreditation of courses for engineering students was evaluated, of the 64 students officially registered in three courses of microbiology, only 90% registered on the Moodle platform to take the online course, 71% of the dynamics were delivered, 67% of the final project and 80% of the delivery of the team's activities were not reached, there was an approval of 54%. Some problems were that videoconferences were not attended and assignments were not turned in

Characterization and in vitro spread of mesquite (Prosopis laevigata (Humb. & Bonpl. ex Willd.) M.C.Johnst.)

Objective: To analyze fruit characteristics, genetic diversity, and in vitro spread of mesquite genotypes (Prosopis laevigata (Humb. & Bonpl.) ex Willd.) from the plains of Ojuelos-Aguascalientes, Mexico. Design/Methodology/Approach: Fruit and leaf samples were collected from 20 mesquite genotypes to analyze and extract DNA to determine their diversity using RAPDs. Simultaneously, in vitro spread tests were performed. Results: The Ojuelos de Jalisco genotype stood out for the weight of its fruits, while La Presa genotype stood out for its degrees Brix. Genotypes were grouped according to their best growth condition for their genetic analysis. In in vitro spread, AG3 with IBA allowed stem/shoot elongation and root formation; meanwhile, AgNO3 prevents leaf fall, allowing rooting and transfer to the soil. Study Implications/Limitations: This study about mesquite (P. laevigata) was limited to the plains of Ojuelos-Aguascalientes. Findings/Conclusions: Mesquite plants from the Ojuelos-Aguascalientes subregion, Mexico, were identified and georeferenced; likewise, a methodology for its in vitro spread was developed

Fruit Damage Patterns Caused by Ovipositing Females of Conotrachelus dimidiatus (Coleoptera: Curculionidae) in Guava Trees

We evaluated the damage patterns produced by females of the guava weevil Conotrachelus dimidiatus Champion, 1904 (Coleoptera: Curculionidae), according to the position of the damaged fruit in guava trees Psidium guajava L. in Calvillo, Aguascalientes, Mexico. The trees were subdivided in eight zones, and during one year the level of fruit lesions due to oviposition was registered. Results showed a higher level of damage in the upper and external zone of the trees (P ≤ .05). We found no significant differences in damage between the four cardinal points (P ≥ .05). During the year, the level of damage was recorded and was higher in the months of August and September (P ≤ .05) associated with rainfall (0.86, P = .06) and increase in temperature (0.84, P = .03). The most susceptible fruits were in the size range of 2.1-4.0 cm (polar diameter). The information from this study will be used to design and establish effective control strategies for the guava weevil, taking into account location of the most susceptible fruits, seasonality of the pest, and the abiotic factors

Control del clavo de la guayaba con extractos de plantas

Los extractos elaborados por maceración alcohólica presentaron la mayor inhibición del crecimiento del hongo P. clavispora con respecto de la maceración en agua o de la infusión. En bioensayos con extractos alcohólicos concentrados con rotovapor y filtrados, los extractos de jaral (Cistus sp.), aceitilla (Bidens odorata Cav.), mezquite (Prosopis laevigata Humb. & Bonpl. ex Willd.), paraíso (Melia azedarach L.), olivo (Olea europaea L.), trompillo (Solanum eleagnifolium Cav.), lantana (Lantana sp.), romero (Rosmarinus sp.), ruda (Ruta graveolens L.), venadilla (Bursera simaruba (L.) SARG.), lengua de vaca (Rumex crispus L.) y eucalipto australiano (Corymbia (=Eucalyptus) gummifera (Gaertn.) Hill & Johnson) mostraron reducciones del crecimiento del hongo, superiores al 90%. En campo, los extractos de plantas de eucalipto rojo (Eucalyptus camaldulensis) y eucalipto australiano (Corymbia gummifera) mostraron menores daños que los fungicidas de síntesis química evaluados. Lo anterior, indica que es factible el uso de estos extractos en el control del hongo P. clavispora, disminuyendo el impacto ambiental.Extracts made by alcoholic maceration, showed the greatest inhibition of the growth of the P. clavisporafungus with respect to water maceration or infusion. In bioassays with alcoholic extracts concentrated with rotary evaporator and filtered, extracts ofjaral (Cistussp.), olives (Bidens odorataCav.), Mesquite (Prosopis laevigataHumb. & Bonpl. Ex Willd.), paradise (Melia azedarachL.), olive tree (Olea europaeaL.), trompillo (Solanum eleagnifoliumCav.), lantana (Lantanasp.), rosemary (Rosmarinussp.), rue (Ruta graveolensL.), venadilla (Bursera simaruba(L.) SARG.), cow tongue (Rumex crispusL.) and Australian eucalyptus (Corymbia (=Eucalyptus) gummifera(Gaertn.) Hill & Johnson) showed fungal growth reductions, greater than 90%. In the field, extracts of red eucalyptus plants (Eucalyptus camaldulensis) and Australian eucalyptus (Corymbia gummifera) showed less damage than chemical synthesis fungicides evaluated. The foregoing indicates that the use of these extracts isfeasible in the control of the P. clavisporafungus, reducing the environmental impact

Phytophthora capsici Epidemic Dispersion on Commercial Pepper Fields in Aguascalientes, Mexico

Chili pepper blight observed on pepper farms from north Aguascalientes was monitored for the presence of Phytophthora capsici during 2008–2010. Initially, ELISA tests were directed to plant samples from greenhouses and rustic nurseries, showing an 86% of positive samples. Later, samples of wilted plants from the farms during the first survey were tested with ELISA. The subsequent survey on soil samples included mycelia isolation and PCR amplification of a 560 bp fragment of ITS-specific DNA sequence of P. capsici. Data was analyzed according to four geographical areas defined by coordinates to ease the dispersal assessment. In general, one-third of the samples from surveyed fields contained P. capsici, inferring that this may be the pathogen responsible of the observed wilt. Nevertheless, only five sites from a total of 92 were consistently negative to P. capsici. The presence of this pathogen was detected through ELISA and confirmed through PCR. The other two-thirds of the negative samples may be attributable to Fusarium and Rhizoctonia, both isolated instead of Phytophthora in these areas. Due to these striking results, this information would be of interest for local plant protection committees and farmers to avoid further dispersal of pathogens to new lands