Host selection behavior of diaeretiella rapae mclntosh [hymenoptera: braconidae] attacking cereal aphids in Upper Egypt

The present investigation was carried out in Assiut Governorate to study the relative abundance of cereal aphid parasitoids and evaluate the host selection and host-instar preference of Schizaphis graminum [Rondani] and Rhopalosiphum padi L. by the braconid parasitoid, Diaeretielia rapae Mclntosh during 2015 wheat growing season

The obtained results revealed that the dominance percentages of the primary parasitoids were so high and presented by 81.53% of the total caught parasitoids* However, the secondary parasitoids showed low dominance percentages and presented by 18.47%

The parasitoids, D. rapae and Alloxysta australiae [Ashmead] revealed the highest dominance percentage and presented by 76.38 and 47.93% of the total collected primary and secondary parasitoids, respectively

The aphid, S. graminum appeared as more relatively preferred for. rapae than K. padi species

The development of D. rapae was found to be possible in any instar of 5. graminum and R. padi

The second and third instars of S. graminum presented the optimal response for D. rapae growth and survival, while the third and fourth instars of R. padi presented the optimal response for parasitization by the same parasitoid species

The averages of the development times from oviposition until the appearance of the mummified aphid were 7.68 and 8.01 days for S. graminum and R. padL respectively. Offspring production per female was high in the adult stage than others. Nymphs parasitized and mummified by D. rapae during the first and second instars may be reach to maturity but not produce any progeny

Structural and functional analysis of cathepsin S of Heterodera spp: A promising candidate for its control.

Cysteine proteinases are required for a wide range of physiological processes in all living organisms. In parasitic nematodes, they are particularly crucial for the digestion of host tissues and evasion of host immune responses. Therefore, in general, these are identified as primary targets for the control of parasitic nematodes. Herein, cathepsin S-like cysteine proteinase of Heterodera avenae (Hacp-s) has been cloned and analysed for the first time. The predicted protein is 298 amino acids long and showed significant similarity with cathepsin S of Heterodera glycines (Hgcp-s). The sequence of cathepsin S contains a signal peptide of 30 amino acids which suggests its role in extracellular functions. Multiple sequence alignment revealed the presence of ERFNIN motif and conserved catalytic residues. Three dimensional structure (3D) of Hgcp-s was modelled using homology modelling. In order to illustrate the plausible mode of interaction of cathepsin S (Hgcp-s), docking analysis was performed with E-64 cysteine proteinase inhibitor. Docking studies revealed the hydrogen bonding of E-64 with Gln153, His299 and Gly203 as well as close interaction with catalytic residues Cys159 and Asn320. Expression analysis of Hacp-s using qRT-PCR showed high expression of cathepsin S in pre parasitic J2s and female stages suggesting its significant role in both pre-parasitic and parasitic stages of the nematode life cycle.

Spread of phosphine resistance among brazilian populations of three species of stored product insects

The resistance to fumigant insecticides in stored-products insects is often recorded. Several factors influence the evolution of insecticide resistance. Among these, the frequency of applications and the migration of resistant populations are of primary importance for the stored-product insects. The aim of this study was to characterize the spectrum and investigate the status of phosphine resistance in Brazil, in 13 populations of the Coleoptera Tribolium castaneum Herbst (Tenebrionidae), ten populations of Rhyzopertha dominica (Fabr.) (Bostrichidae), and eight populations of Oryzaephilus surinamensis (L.) (Silvanidae). The pattern of resistance dispersion in the populations of these species was also verified. The bioassays for the detection of phosphine resistance followed the FAO standard method. To test the influence of migration in the evolution of the phosphine resistance, the difference of mortality in the discriminating concentration and the geographical distance among each pair wise combination of collection sites were correlated. None of the populations exhibited mortality above 90 percent in the discriminating concentration, for the three species. Mortality in the discriminating concentration increased with the geographical distance for R.dominica and O.surinamensis. However, no significant linear response was observed among the variables for T.castaneum populations. These results suggest that the dispersion of insects and the local selection are relevant in the evolution of the phosphine resistance in populations of R.dominica and O.surinamensis. In contrast, grain trade and local selection are probably the factors that determine the evolution of the phosphine resistance in populations of T. castaneum.

Classificaçäo macroscópica, identificaçäo da microbiota fúngica e produçäo de aflatoxinas em híbridos de milho / Macroscopic classification, identification of fungal microbiota and aflatoxins production in cron hybrids

Com o objetivo de medir o potencial de resistência de 5 diferentes híbridos de milho, logo após a colheita, ao crescimento de fungos e produçäo de aflatoxinas (AFs), foram avaliados os seguintes parâmetros: 1) aspecto macroscópico dos gräos, sendo os gräos de cada híbrido classificados como íntegros, danificados por insetos (DI) ou danificados por fungos (DF); 2) contaminaçäo fúngica dos híbridos; 3) potencial para resistência à produçäo de AFs, através do cultivo de Aspergillus parasiticus, linhagem NRRL 2999, sobre gräos de cada híbrido estudado; 4) consumo de matéria seca dos híbridos pelo cultivo fúngico. Como resultado, observou-se que 38 por cento do milho de todos os híbridos apresentaram comprometimento macroscópico, sendo 26,7 por cento DI e 11,3 por cento DF. Os híbridos recém-colhidos apresentaram contaminaçäo fúngica por Penicillium sp. (14,3 por cento); Aspergillus sp. (23,6 por cento) e Fusarium sp. (57,1 por cento). O potencial de produzir AFs pelos diferentes híbridos em cultivos por 5 e 10 dias apresentou diferença somente com relaçäo à aflatoxina G2 em cultivos por 5 dias. A média de consumo de matéria seca dos híbridos de milho foi de 1,25 e 2,69 por cento submetidos ao cultivo de fungos por períodos de 5 e 10 dias, respectivamente.

Alcaloides del claviceps spp en sorgo del estado de Morelos, México / Claviceps spp alkaloids in sorghum from the state of Morelos in Mexico

La información del presente escrito es con el fin de dar a conocer la identificación de alcaloides del hongo Claviceps spp en sorgo proveniente del estado de Morelos, México. Se describe el ciclo de vida de Claviceps purpurea (ergot o cornezuelo), sus caracterísicas macroscópicas, toxicidad, número de esclerosis necesarias para inducir la intoxicación, efectos farmacológicos de los alcaloides (ergonovina y engotamina), signos clínicos y hallazgos de necropsia de la intoxicación por alcaloides del Claviceps purpurea. Y finalmente se describe la identificación de tres compuestos (alcaloides) por cromatografía de capa fina en el sorgo del estado de Morelos; con comportamiento igual al de derivados del maleato de ergonovina, pero sin reaccionar al colorante de van Urk

Aislamiento, identificación y determinación de la capacidad toxicogénica de hongos contaminantes de cereales y productos alimenticios / Isolation, identification and determination of the toxicogenic capacity of fungi contaminating cereals and alimentary products

Se determinó en la ciudad de Santa Fe y su zona de influencia, la capacidad toxicogénica, mediante la aplicación de ensayos biológicos rápidos, a hongos contaminantes de cereales y productos alimenticios elaborados con ellos. Los alimentos estudiados fueron: soja, maíz, trigo y sus derivados: los géneros frecuentes aislados fueron: aspergillus, penicillium y fusarium, identificandose las especies de aquellos que resultaron toxicogénicos. Las acciones citotóxicas detectadas mediante los ensayos aplicados fueron: capacidad mutagénica, hemólisis de glóbulos rojos humanos y elongación e inhibición de células de bacillus thuringiensis

Interacción de dos hongos toxicogénicos con una cepa de streptomyces sobre el desarrollo de plantas de trigo / Interaction of 2 toxigenic fungi with a strain of streptomyces on the development of wheat seeds

Entre los microorganismos antagonistas de los suelos donde se cultivan cereales se hallan Streptomyces capaces de producir sustancias inhibidoras que pueden afectar la viabilidad y capacidad de diseminación de distintas especies de Aspergillus y Fusarium y su capacidad para producir aflatoxinas y trichotecenos. El objetivo del presente estudio fue evaluar el efecto de la interacción entre hongos toxicogénicos (Aspergillus parasiticus y Fusarium tricinctum NRRL 3299) y Streptomyces sp.antagónicos del crecimiento de tales hongos sobre el desarrollo de plantas de trigo. Se realizaron las siguientes actividades: a)inoculación de semillas de trigo, con el Streptomyces inhibidor, b) estudio del poder germinativo de las semillas de trigo, c) cultivo en cámara invernáculo de semillas inoculádas y sin inocular sembradas en tierras con y sin los hongos toxicogénicos, d) comprobación de la invasividad o ataque de los hongos mediante el rociado de espigas de plantas provenientes de suelos infectados con una suspensión de conidios de los hongos infectantes, e) determinación de las variaciones en las características botánicas de las plantas de trigo. Se pudo concluir que: 1) la presencia de hongos toxicogénicos no alteró el poder germinativo de las semillas de trigo, 2) el desarrollo vegetal, número y peso promedio de los granos de las plantas provenientes de suelos infectados con los hongos toxicogénicos fué significativamente mayor al de las plantas crecidas en tierra estéril, 3) el estudio anatómico de las plantas no puso en evidencia invasión o ataque por parte de los hongos