At least 59 maize races (Zea mays L.) have been registered in Mexico. The feeding damage caused by insects and mites to maize crops generates up to ~30% of maize yield losses. Spider-mite-resistant plants are needed. The red spider mite, Tetranychus merganser Boudreaux (Acari: Tetranychidae), is distributed in the United States, China, Mexico, and Thailand. It is considered a potential pest in Mexican agriculture. The aim of this study was to evaluate the resistance mechanisms (antixenosis and antibiosis) of 11 native maize populations, representative of each race of maize grown in Tamaulipas, Mexico, to T. merganser under laboratory conditions. The aim was also to obtain information on the chemical composition and some morphological characteristics of these maize races and to identify resistant maize races for incorporation into a breeding program. Antixenosis was assessed by non-preference for oviposition and feeding. Antibiosis was measured by growth rate (ri). The presence of secondary metabolites in the 11 maize races were different. In the 11 maize races, quantitative analysis of total phenol concentration, total flavonoid concentration, and antioxidant capacity were significantly different. The multivariate analysis of variance showed that there is evidence of antixenosis noted by maize race differences in egg laying and percentage feeding damage but not of antibiosis noted by growth rate. Red spider mites laid significantly more eggs on the Celaya (24 h: 25.67 ± 17.04, 48 h: 42.67 ± 26.86, 72 h: 49.33 ± 28.54) race than on Raton (24 h: 7.00 ± 5.00, 48 h: 12.67 ± 8.02, 72 h: 14.67 ± 9.29) and Elotes Occidentales × Tuxpeño (24 h: 9.67 ± 5.85, 48 h: 15.33 ± 10.69, 72 h: 17.67 ± 10.97) races. However, the growth rate and mortality of T. merganser in the 11 corn races were similar. The Vandeño (24 h: 11.67 ± 2.89, 48 h: 27.67 ± 7.64, 72 h: 30.00 ± 18.03) and Tabloncillo × Tuxpeño (24 h: 18.33 ± 7.64, 48 h: 25.00 ± 8.66, 72 h: 25.00 ± 8.66) races were the most resistant to red spider mite damage, whereas the most susceptible race was Celaya (24 h: 26.67 ± 15.28, 48 h: 48.33 ± 29.30, 72 h: 65.00 ± 30.00). Further analysis by PCA at 24, 48, and 72 h found the Celaya race positively correlated to growth rate and oviposition of T. merganser and to a lesser extent with the percentage of feeding damage, suggesting that the Celaya race was most susceptible to T. merganser. At 24 h, the Vandeño race was most resistant, given a negative correlation to growth rate and oviposition by T. merganser. The PCA at 48 and 72 h noted the Elotes Occidentales × Tuxpeño race was most resistant to red spider mite, with negative relationships to growth rate and oviposition and, to a lesser extent, to feeding damage. This resistance is due to the differences in both its morphological characteristics and the secondary metabolites present in their leaves.

In vitro antibacterial activity of Magnolia tamaulipana against tomato phytopathogenic bacteria | Julio Chacón-Hernández, Roberto Arredondo-Valdés, Francisco Reyes-Zepeda, Francisco D. Hernández-Castillo, Julia C. Anguiano-Cabello, Rapucel T. Q. Heinz-Castro, Sandra G. Mora-Ravelo | Agricultural Journals

Systematic reviews and meta-analytical approach are a tool used in different social and biological disciplines, but its application in evaluating ethnobiological information is scarce. Thus, through this analytical approach, we seek to answer if there are any patterns in the mexican ethnozoological scientific production. We searched for studies published between 2005 and 2015 in catalogues, repositories and databases. For evaluating significative differences among seven variable datasets, we first used non parametric Kruskal-Wallis tests and then Tukey multiple comparison tests. We also determined the link between researchers and institutions with a multidimensional non-metric scaling analysis. We found 295 published studies, book chapters were the most representative (27%), diffusion articles (20%), impact factor articles (15%) and indexed articles (14%). There are significant differences in the number of publications among the evaluated years, among thematic areas, study focus (qualitative/quantitative), ethnographic and biological methods. Regarding academic linking, we identified 94 author adscription institutions, however, no research networks were identified. Our results suggest that the amount, diffusion and reach of mexican ethnozoological production show a tendency to non-periodic publishing, predilection for qualitative approach, a low use of statistical and ethnobiological analysis, as well as an inadequate selection of biological methods. We suggest this data analysis approach will allow a better standardization for information taking and processing, aiding the discipline in its growth and consolidation.

Magnolia tamaulipana powder extract inhibited egg laying and food intake of adult female Tetranychus urticae. These effects increased according to concentration, being highly effective between 500 and 1000 µg/mL. Thus, this powder extract shows promise as a control agent for spider mites.

Red spider mite, Tetranychus merganser Boudreaux (Acari: Tetranychidae), has increased its host plants and causes severe damage and defoliation. Control of pest mites depends mostly on the use of agrochemicals. Mite-resistant plants are needed. Piquin chili, Capsicum annuum var. glabriusculum (Dunal) Heiser & Pickersgill, is a wild species of chili pepper and a major source of phytochemical compounds such as phenolic compounds, flavonoids, capsaicinoids, carotenoids, tocopherols, ascorbic acid, and volatile compounds. The aim of this study was to evaluate antibiosis and antixenosis as resistance mechanisms in three accessions (BGH-425, BGH-426, and Ch) of piquin chili in laboratory and greenhouse conditions. In the laboratory, antixenosis was evaluated by non-preference for oviposition, antibiosis by infinitesimal rate of increase (r) and finite rate of increase (λ), and repellency by percentage of mites killed. In the greenhouse, antibiosis was evaluated by r and λ. Preference for the lower or upper leaf surface was evaluated. Antixenosis, antibiosis, and repellency were observed in the three piquin chili accessions. In the laboratory, females survival was 60, 80, 80 and 93.33% on BGH-426, BGH-425, Ch and bean (Phaseolus vulgaris L.), respectively. The lower r was observed on Ch accession (0.3857 day-1) and the higher on bean (0.6105 day-1). The λ ranged from 1.47 on Ch to 1.84 on bean. In the greehouse, the highest and the lowest values of the r y λ were obtained at bean (0.6014 day-1 and 1.82) and Ch accession (0.3591 day-1 and 1.43), respectively. Red spider mite preferred to colonize the lower leaf surface of the three piquin chilis and bean. The three accessions of piquin chili were most resistant to T. merganser.