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Resumen. Para identificar las especies de hemipteros que inciden en el cultivo de fresa (Fragaria × ananassa) (Weston) Duchesne (Rosaceae) producida en campo y en macrotunel, en tres localidades de Irapuato, Guanajuato, Mexico y la influencia de las condiciones ambientales sobre la fluctuacion de sus poblaciones, se cuantifico el numero de ninfas y adultos mediante capturas semanales, de octubre de 2010 a diciembre de 2011, registrando ademas la temperatura y la humedad relativa. En total se recolectaron 9,822 especimenes de tres especies identificadas, de los cuales, 9% fueron de Lygus lineolaris Hahn, 1833; 22% de Neopamera bilobata (Say, 1832), y 69% de Nysius raphanus Howard, 1872, constituyendo estas ultimas dos especies, el primer registro en fresa para Mexico. De acuerdo con los coeficientes de correlacion de Spearman, se concluyo que la humedad relativa tuvo mayor influencia que la temperatura sobre la densidad de chinches, ya que las ninfas de N. raphanus disminuyeron a medida que la humedad rela...

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Zymography of alcohol dehydrogenase (ADH) activity in the entomopathogenic fungus Metarhizium anisopliae grown under various conditions revealed that micro-aerobic growth was associated with increased ADH activity. The major ADH protein, AdhIp, was purified to homogeneity by affinity chromatography and has an estimated molecular weight of 41 kDa and an isoelectric point (p I ) of 6.4. Peptide mass fingerprint analysis allowed the identification and cloning of the gene that encodes this protein, Adh1 , as annotated in the M. anisopliae genome database. AdhIp is related to the medium-chain dehydrogenase/reductase (MDR)/zinc-dependent alcohol dehydrogenase-like family and contains conserved ADH sequence motifs, such as the zinc-containing ADH signature, the FAD/NAD binding domain and amino acid residues that are conserved in most microbial ADHs. Semi-quantitative RT-PCR analysis revealed that Adh1 gene expression occurs at low levels during early Plutella xylostella infection and that the Adh1 gene was primarily expressed at larval death and as mycelia emerge from the insect cuticle before conidiation. Antisense-RNA experiments indicated that NAD + -dependent ADH activity was diminished by 20–75% in the transformants, and the transformants that had lower ADH activity showed allyl alcohol resistance, which indicates that reduction in ADH activity also occurs in vivo . Bioassays performed using antisense adh1 transformants, which have lower ADH activity, showed that LC 50 values were two to five times higher than the wild-type, indicating that AdhIp is required for full capability of the fungus to penetrate and/or colonize the insect.

The external morphologies of the eggs of seven species of grasshoppers were studied with the aid of an electron microscope. The species were Boopedon diabolicum Bruner, Schistocerca cohni Song, Sphenarium purpurascens (Charpentier), Brachystola mexicana Bruner, Melanoplus differentialis (Thomas), Syrbula admirabilis (Uhler), and Melanoplus lakinus (Scudder). The eggs were elongated with rounded ends and provided reliable characteristics that allow identification of the seven species. Eggs of some of the seven species were hexagonal. Brachystola mexicana and Sphenarium purpurascens produced fewer eggs that were larger. The differential characteristics of the seven species and their general systematics are described to differentiate the taxa.

This work outlines the factors that influence the adecuate use of biological control agents such as: the precise identification of the species of the insect pest and the biological control agent that will be used, the parasitic ability and the consumption of the parasite and plunderer respectively, the factors that should be considered in a Biological Control program, and the biotic and a bioticfactors that influence the liberations of the natural enemies.Este trabajo señala los factores que influyen en el uso adecuado de los agentes de control biológico tales como: la identificación precisa de la especie del insecto plaga y del agente de control biológico que se empleará, la capacidad de parasitismo y consumo del parásito y depredador respectivamente, los factores que se deben tomar en cuenta para establecer un programa de Control Biológico, y los factores bióticos y abióticos que influyen en las liberaciones de los enemigos naturales.

The population dynamics of the agave scale, Acutaspis agavis (Townsend and Cockerell), on Agave tequilana Weber var. azul were studied in the state of Guanajuato, Mexico. Weekly samples were taken of plants to monitor for the presence of scales and to quantify the different developmental stages of the diaspid, together with its parasitoids and predators. Results showed some reproductive activity throughout the year, with two peaks in the abundance of eggs and first-instar nymphs in May and September, suggesting two generations annually of scales occur in the study area. First-instar nymphs within scales and “crawlers” increased in abundance from April through May and from August through early October, with these differences generally being significantly greater than during winter and mid-summer months. The predatory coccinellid Chilocorus cacti fed on the scale and increased in abundance from August to December when eggs and young scales were most abundant. Parasitism by Aphytis spp. occurred thr...

Population growth curves in three species of Diabrotica in the region of Irapuato, Guanajuato, Mexico, were estimated using multivariate multiple regression techniques through a third-degree polynomial function defined by: where T is the average monthly standard temperature, PP is the average monthly accumulated rainfall, and Y1, Y2, and Y3 are the numbers of Diabrotica undecimpunctata (Harold), Diabrotica balteata (LeConte), and Diabrotica virgifera (Krysan & Smith) adults, respectively. The Roy criterion was used in the multivariate analysis of variance (MANOVA) of the multivariate multiple regression, which statistical test value was 95.2 with a probability for its corresponding approximation F of 8.548e-05. Consequently, the estimated polynomials for the population growth curves were adequate. Multivariate association measures Wilks (Λ = 0.9984) and Roy (θ = 0.9896) were calculated, allowing estimation of growth curves as prediction tools. These models of polynomial growth curves were compar...