Distribución espacial de bracónidos (Hymenoptera) reportados en el estado de Oaxaca

Se presenta un listado de 300 morfoespecies, de las cuales se determinaron 83 especies y 146 géneros de Braconidae en el estado de Oaxaca. Se analizó la distribución espacial de los bracónidos registrados y se georreferenciaron los datos. Elaborándose un Sistema de Información Geográfica con los datos de cada especie registrada en literatura y material depositado en colecciones científicas. Las regiones con mayor abundancia de géneros fueron Costa, Valles Centrales e Istmo y las subfamilias más diversas fueron Agathidinae y Doryctinae. Para la selva mediana subperennifolia, se registró el mayor número de géneros (81), entre los más representativos se encontraron Heterospilus, Opius y Bracon.  En zonas con temperaturas cálidas se registró el 85 % de los géneros, incluyendo representantes de las subfamilias Alysiinae, Euphorinae, Doryctinae y Microgastrinae. El clima con mayor presencia de bracónidos fue el cálido subhúmedo y las subfamilias más abundantes fueron Doryctinae y Microgastrinae. En el clima semicálido subhúmedo se encontraron especialmente especímenes de Agathidinae. Los parasitoides se distribuyeron desde los 20 a 2900 msnm, pero el mayor número de registros se encontró a una altitud de 736 m y el género Heterospilus fue el mejor representado

Alternativas biorracionales para el control de paratrioza bactericera cockerelli sulcer (hemiptera: psyllidae) en laboratorio

Aún cuando el empleo de sustancias químicas para el control de insectos plagas se considera hasta hoy, como el método más efectivo para mantener las poblaciones a niveles no perjudiciales, actualmente su uso resulta impráctico debido, entre otras razones, al desarrollo de poblaciones resistentes, a la presencia de residuos inherentes a su uso y a las fuertes restricciones comerciales que prevalecen. El psílido de la papa, Bactericera cockerelli (Sulc) (Hemíptera: Psyllidae), se ha convertido recientemente en motivo de gran preocupación debido a su impacto destructivo sobre la papa, tomate y otros cultivos de solanáceas en los Estados Unidos, México, América Central y Nueva Zelanda

Antimicrobial engineered nanoparticles in the built cultural heritage context and their ecotoxicological impact on animals and plants: a brief review

Abstract Nanoparticles (NPs) of metal oxides, sometimes referred to as engineered nanoparticles have been used to protect building surfaces against biofilm formation for many years, but their history in the Cultural Heritage world is rather short. Their first reported use was in 2010. Thereafter, a wealth of reports can be found in the literature, with Ti, Ag and Zn oxides being the major protagonists. As with all surface treatments, NPs can be leached into the surrounding environment, leading to potential ecotoxicity in soil and water and associated biota. Dissolution into metal ions is usually stated to be the main mode of toxic action and the toxic effects, when determined in the marine environment, decrease in the order Au > Zn > Ag > Cu > Ti > C60, but direct action of NPs cannot be ruled out. Although ecotoxicity has been assessed by a variety of techniques, it is important that a suitable standard test be developed and the European Unions’s Biocidal Product Registration group is working on this, as well as a standard test for antimicrobial efficacy to determine their impact on ecological processes of surrounding non-target organisms and their transformation products under realistic scenarios

Effects of aqueous and ethanol extract of dried leaves of Pseudocalymma alliaceum (Bignonaceae) on haematological and biochemical parameters of wistar rats

Objective: To perform the toxicological evaluation of aqueous and ethanol extract of dried leaves of Pseudocalymma alliaceum (P. alliaceum) in male Wistar rats by oral administration for 14 days, and to determine the biochemical and haematological status of blood. Methods: The animals were completely randomized into four groups of three rats each. Results: No deaths were reported after oral administration of the extracts, no physical signs of toxicity or adverse effects were observed. Hematological indices of red blood cell count, hemoglobin concentration and mean corpuscular hemoglobin showed no significant abnormality; however, white series levels decrease presenting a leukopenia. Glucose, creatinine and albumin increased, while urea decreased; aspartate aminotransferase values decreased with the aqueous extract at 50 and 100 mg/kg and increased with dose of 200 mg/kg, in contrast ethanol extract caused an increase in this parameter to the doses used. The alanine aminotransferase decreased with aqueous extract and increased with ethanol extract. Triglycerides decreased when used aqueous extract and reduced with ethanol extract at 100 and 200 mg/kg, in contrast to 50 mg/kg decreased to be compared with control group. Conclusions: The daily intake of P. alliaceum did not produce acute toxicity to 50 mg/kg which may be interpreted as toxic signs or biological damage, but liver and renal function changes at dosages of 100 and 200 mg/kg; however, the reduction ability of white blood cells count could be used as a basis for specific studies on the treatment of patients with leukemia

Effect of Habitat Complexity on Parasitic Efficiency of Romanomermis iyengari1 on Larvae of the Mosquito Culex quinquefasciatus

Indiscriminate use of insecticides to control vectors of malaria, dengue, and yellow fever contaminates the environment and with time, gradually increases insecticide-resistant mosquitoes, making their control increasingly difficult. Use of the parasitic nematode Romanomermis iyengari (Mermithidae) is efficient biological control against mosquitoes, but little is known of the effect of habitat complexity on the success of infection. We determined lethal doses of the nematode on Culex quinquefasciatus (Culicidae) and analyzed the effect of habitat complexity (0, 25, 50, 75, and 100% aquatic debris cover) on successful infection by two lethal loads (10 and 100 parasites per larva). Habitat complexity had no effect on parasitic efficiency of R. iyengari at high concentrations (100 parasites per larva) and significantly decreased parasitic efficiency at low concentrations (10 parasites per larva). Use of combined biological control agents (water bugs (Hemiptera), odonate nymphs (Odonata), and air-breathing fish) of mosquito larvae commonly found in larval habitats should be studied more. Habitat complexity could have a density-dependent effect on parasitic efficiency of R. iyengari on Cx. quinquefasciatus. Complex habitat could affect mobility and ability of a parasite to search for a host. High parasite loads were not affected by habitat complexity and caused high parasite burdens on sampled hosts. Mosquito larvae could reach maturity without being infected by R. iyengari in low parasite loads

Colletotrichum brevisporum and C. musicola Causing Leaf Anthracnose of Taro (Colocasia esculenta) in Mexico

Taro (Colocasia esculenta var. antiquorum), family Araceae, is an important tropical crop cultivated throughout the world for its edible corms. During the summer of 2017, irregular brown lesions, typical of anthracnose were observed on approx. 40% of taro plants in a commercial orchard located in San Juan Bautista Tuxtepec, Oaxaca, Mexico. Small pieces of the lesions of five symptomatic leaves were surface disinfected with 1% NaOCl for 2 min followed by rinsing with sterile distilled water and plated on potato dextrose agar plates which were then incubated at 25°C for 5 days in darkness. Colletotrichum-like colonies were consistently isolated and 10 monoconidial isolates were obtained. Two isolates were selected as representatives for morphological characterization, multilocus phylogenetic analysis, and pathogenicity tests. The isolates were designated as UACH289 and UACH290 and were deposited in the Culture Collection of Phytopathogenic Fungi at the Chapingo Autonomous University. Conidia (n = 100) of isolate UACH289 were cylindrical, hyaline, aseptate, 15.1 to 18.4 × 4.4 to 5.2 μm, with the apex rounded and the base, rounded to truncate; appressoria (n = 20) were single, dark brown, and with undulate or lobate margin. Whereas conidia (n = 100) of isolate UACH290 were cylindrical to ellipsoidal, hyaline, aseptate, 12.3 to 17.0 × 3.8 to 5.0 μm; appressoria (n = 20) were irregular, bullet-shaped to elliptical, dark brown, with undulate or lobate margin. For molecular identification, the internal transcribed spacer (ITS) region (White et al. 1990), and fragments of actin (ACT), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and β-tubulin (TUB2) genes were amplified by PCR (Weir et al. 2012), and sequenced. A phylogenetic analysis based on Bayesian inference and including published ITS, ACT, GAPDH, and TUB2 data for Colletotrichum species was performed. After phylogenetic analysis, isolates UACH289 and UACH290 clustered with C. brevisporum (Accessions nos. ITS: MK862121; ACT: MK862124; GAPDH: MK862122; and TUB2: MK862123) and C. musicola (Accessions nos. ITS: MK882586; ACT: MK882589; GAPDH: MK882587; and TUB2: MK882588), respectively. Pathogenicity of the fungi was verified by spraying conidial suspensions (1 × 106 spores ml-1) on the upper surface of 10 taro leaves. Ten control leaves were sprayed using sterilized water. All plants were kept under greenhouse conditions at 25°C for 10 days. Anthracnose symptoms were observed on all inoculated leaves after 12 days, whereas control leaves remained symptomless. Koch´s postulates were fulfilled when the fungi were re-isolated 100% from the diseased leaves. The experiment was performed twice. Colletotrichum brevisporum has been previously reported as a pathogen on several crops including Annona muricata, Carica papaya, Sechium edule, Capsicum annuum, Passiflora edulis, Citrus medica, P. edulis, Cucurbita moschata, and C. pepo (Farr and Rossman 2019), whereas Colletotrichum musicola only has been associated with Musa sp. in Mexico (Damm et al. 2019). To our knowledge, this is the first report of C. brevisporum and C. musicola causing leaf anthracnose of taro in Mexico and worldwide.Fil: Vásquez-López, Alfonso. Instituto Politécnico Nacional. Unidad Oaxaca; MéxicoFil: Palacios-Torres, Rogelio Enrique. Universidad del Papaloapan, Instituto de Agroingeniería; MéxicoFil: Camacho-Tapia, Moises. Universidad Autónoma de Chapingo; MéxicoFil: Granados-Echegoyen, Carlos. Universidad Autónoma de Campeche; MéxicoFil: Bernardi Lima, Nelson. Instituto Nacional de Tecnologia Agropecuaria. Centro de Investigaciones Agropecuarias. Unidad de Fitopatologia y Modelizacion Agricola. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Cordoba. Unidad de Fitopatologia y Modelizacion Agricola.; ArgentinaFil: Vera-Reyes, Ileana. Universidad Autonoma Chapingo; MéxicoFil: Tovar Pedraza, Juan Manuel. Universidad Autonoma Chapingo; MéxicoFil: Leyva-Mir, Santos Gerardo. Universidad Autonoma Chapingo; Méxic

Functional and Quality Assessment of a Spore Harvester for Entomopathogenic Fungi for Biopesticide Production

The Green Revolution led to an increased use of synthetic pesticides, causing environmental pollution. As an alternative, biopesticides made from entomopathogenic agents such as fungi have been sought. This study aimed to design and evaluate the performance of a harvester machine for efficiently collecting entomopathogenic spores of Metarhizium anisopliae and Beauveria bassiana grown on rice and corn substrates. The spore yield was estimated, and a spore count and a colony-forming unit (CFU) count were performed. Statistical analysis was conducted to compare the mean values of spores obtained from different combinations of solid substrate and fungi. The Corn-Metarhizium combination produced 34.15 g of spores per kg of substrate and 1.51 × 109 CFUs mL−1. Similarly, the Rice-Metarhizium combination produced 57.35 g per kg and 1.59 × 109 CFUs mL−1. Meanwhile, the Corn-Beauveria combination yielded 35.47 g per kg and 1.00 × 109 CFUs mL−1, while the Rice-Beauveria combination had a yield of 38.26 g per kg and 4.50 × 108 CFUs mL−1. Based on the reported results, the Rice-Metarhizium combination appears to be the most effective, yielding the highest number of harvested spores per kg of substrate. The study estimated a total cost of approximately $409.31 for manufacturing the harvester, considering only the cost of the materials. These results could potentially increase the availability and affordability of entomopathogenic fungi in integrated pest management

Efficiency of Schinus molle Essential Oil against Bactericera cockerelli (Hemiptera: Triozidae) and Sitophilus zeamais (Coleoptera: Dryophthoridae)

The present study determines the chemical composition of Schinus molle essential oil and its mortality and repellent effect on Bactericera cockerelli immature stage and Sitophilus zeamais adults. Twenty-four compounds were identified and the most abundant were o-Cymene (29.04), 1R-α-Pinene (15.52), camphene (14.00), and β-myrcene (11.54). On the fifth-instar psyllid nymph, the LC50 and LC90 at 48 h were 442.67 and 864.29 ppm, and for the fourth-instar were 273.41 and 534.67 ppm. The maize-weevil registered an LC50 and LC90 of 343.25 and 986.96 ppm for the fifteenth day. A selection index (Si) of 0.37 with 800 ppm was registered, showing the highest repellent activity, while with the lowest concentration (50 ppm), non-repellent activity was recorded. However, all concentrations above 100 ppm showed repellency against the maize weevil. The study reveals, for the first time, the essential oil’s insecticidal effects on the fourth and fifth nymphal stage of the potato/tomato psyllid B. cockerelli and the usefulness of the essential oil as a repellent against adult of S. zeamais. The Si effect on maize weevil was grouped into categories

Efficiency of <i>Schinus molle</i> Essential Oil against <i>Bactericera cockerelli</i> (Hemiptera: Triozidae) and <i>Sitophilus zeamais</i> (Coleoptera: Dryophthoridae)

The present study determines the chemical composition of Schinus molle essential oil and its mortality and repellent effect on Bactericera cockerelli immature stage and Sitophilus zeamais adults. Twenty-four compounds were identified and the most abundant were o-Cymene (29.04), 1R-α-Pinene (15.52), camphene (14.00), and β-myrcene (11.54). On the fifth-instar psyllid nymph, the LC50 and LC90 at 48 h were 442.67 and 864.29 ppm, and for the fourth-instar were 273.41 and 534.67 ppm. The maize-weevil registered an LC50 and LC90 of 343.25 and 986.96 ppm for the fifteenth day. A selection index (Si) of 0.37 with 800 ppm was registered, showing the highest repellent activity, while with the lowest concentration (50 ppm), non-repellent activity was recorded. However, all concentrations above 100 ppm showed repellency against the maize weevil. The study reveals, for the first time, the essential oil’s insecticidal effects on the fourth and fifth nymphal stage of the potato/tomato psyllid B. cockerelli and the usefulness of the essential oil as a repellent against adult of S. zeamais. The Si effect on maize weevil was grouped into categories