RESUMEN

We found substantial variation in resistance to the fly-specific pathogen Entomophthora muscae 'Berkeley' (Entomophthoromycota), in 20 lines from the Drosophila melanogaster Genetic Reference Panel (DGRP). Resistance to E. muscae is positively (r = 0.55) correlated with resistance to the broad host range ascomycete entomopathogen Metarhizium anisopliae (Ma549), indicative of generalist (non-specific) defenses. Most of the lines showing above average resistance to Ma549 showed cross-resistance to E. muscae. However, lines that succumbed quickly to Ma549 exhibited the full range of resistance to E. muscae. This suggests fly populations differ in E. muscae-specific resistance mechanisms as well as generic defences effective against both Ma549 and E. muscae. We looked for trade-offs that could account for inter-line variation, but increases (decreases) in disease resistance to E. muscae are not consistently associated with increases (decreases) of resistance to oxidative stress, starvation stress and sleep indices. That these pathogens are dynamic agents of selection on hosts is reflected in this genetic variation for resistance in lines derived from wild populations.

Asunto(s)

Asunto(s)

RESUMEN

Thrips of late are becoming more resurgent in agro-ecosystems especially in India and South Asian countries. One of the reasons attributed is the development of resistance in them to groups of insecticides of organo phosphates, carbamates, synthetic pyrethroids, etc., which form the core of recommendation for thrips management. The chilli thrips, Scirtothrips dorsalis Hood, is no exception and is tending to be an unmanageable pest. In S. dorsalis, besides evidence of resistance, elimination of natural enemies like Orius sp. is evident, which also probably explains the thrips resurgence. Scirtothrips dorsalis is highly polyphagous and of late has become serious on grapes. The damage is manifested as scab on fruit rind, affecting internal and export markets. Fortunately, it does not vector any virus on grapes in India. Farmers have been reporting inefficacy of established chemicals like acephate, dimethoate, monocrotophos, etc. As grapes is an important cash crop of horticulture, management through insecticides, require alternate or new insecticides. So two trials in 2005 on cv. Bangalore Blue following April and October prunings were conducted at the Indian Institute of Horticultural Research (IIHR), Bangalore, S. India to evaluate two doses of a newer molecule viz. Clothianidin [Dantop] on S. dorsalis. Clothianidin 0.006%, Clothianidin 0.008% were compared with monocrotophos 0.05%, dimethoate 0.06% and acephate 0.1125%. There was an untreated check. Each treatment was replicated five times; a vine constituted a replicate. These data were subjected to ANOVA, after arc sine transformation. The critical difference (CD) at p < 0.05 was the test criterion. In the first trial it was found that all the insecticides tried were superior to check and were on par at p < 0.05. However, Clothianidin 0.008% gave the best control with a low mean of 0.26% berry damage/bunch as compared to 4.42% in the unsprayed check. The trend was the same in the second trial also with Clothianidin 0.008% giving the best control with 0.64% berry damage/bunch as compared to 8.49% in the unsprayed check. It was on par with acephate and monocrotophos, but significantly superior to Clothianidin 0.006% and dimethoate.

Asunto(s)

RESUMEN

La conidiobolomicosis es una micosis subcutánea que se localiza generalmente en la línea media facial; es causada por un hongo saprófito de suelos y vegetales secos, propio de regiones intertropicales, que afecta principalmente a hombres adultos. El agente etiológico C onidiobolus coronatus pertenece a la clase de los Zigomicetos, orden Entomoftorales; se caracteriza por hifas cortas y gruesas, generalmente aseptadas, que crece entre 30°C y 37°C y produce granulomas nasales. Se informan a continuación los hallazgos histológicos de un caso de conidiobolomicosis en un paciente de 31 años de raza negra, natural y procedente de la región de Urabá, quien presentaba deformidad mediofacial con edema de nariz, labio superior e imágenes polipoides en senos maxilares con destrucción del tabique nasal. La biopsia demostró inflamación granulomatosa necrosante difusa en la dermis profunda e hipodermis asociada con eosinófilos y fenómeno de Splendore-Hoeppli, en cuya zona central se ubicaban espacios aparentemente vacíos que contenían el hongo que no se tiñó con HE, pero que sí lo hizo con las coloraciones de PAS y Grocott lo cual permitió la observación de hifas de paredes gruesas y rígidas, con torsión central y extremos cónicos

Asunto(s)

Asunto(s)

Asunto(s)

RESUMEN

From 1983 through 1988, a total of 1,762 collections, containing 31,312 individuals of the mole cricket, Scapteriscus borellii, were made, principally in the State of São Paulo, Brazil. Collections were found to fit a negative binomial distribution both as whole and when divided into monthly collections. In these collections, an iridovirus, a entomogenous nematode, and the fungi Metarhizium anisopliae, Beauveria bassiana, Paecilomyces sp., and Entomophtora sp., were found to be agents of natural mortality, although usually as endozootics and relatively rarely as epizootics and panzootics. As a group, these diseases were also distributed in a binomial negative. These data suggest that the temporal and spatial aggregations of the mole crickets, produced by high rates of migration among suitable habitats, are adaptations to outbreaks of epidemics, which also serve as mole cricket population regulators. These ideas are develop and derived from simple mathematical models of population change.

Asunto(s)

RESUMEN

Durante levantamentos realizados de 1983 a 1988, um total de 1.762 coletas, totalizando 3.312 indivíduos da paquinha, Scapteriscus borellii, foram feitas, principalmente no Estado de Säo Paulo, Brasil. As coletas ajustavam-se bem na totalidade, a uma distribuiçäo binomial negativa e também quando decomposta a coletas mensais. Das coletas, um iridovirus, um nematóide entomogênico, e os fungos Metarhizium anisopliae, Beauveria bassiana, Paecilomyces sp., Aspergillus sp., Sorsporella sp., e Entomophtora sp., foram encontrados como agentes de mortalidade natural, ainda que como endozoóticos e relativamente rara como epizoóticos ou panzoóticos. Como um conjunto, as doenças também foram distribuídas em forma binomial negativa. Estes dados implicam que as agregaçöes temporais e espaciais das paquinhas, determinadas por taxas elevadas de migraçäo entre habitats apropriados, säo respostas para enfrentar os surtos de doenças que também servem como reguladoras dos níveis populacionais da paquinha. Essas idéias säo desenvolvidas e derivadas de modelos matemáticos simples de mudanças de populaçöes

Asunto(s)

Asunto(s)

RESUMEN

No one of the 3 specific egg yolk fractions (neutral lipids, polar lipids and proteins) was necessary for growth and sporulation of species such as Entomophthora aphidis, E. phalloides and E. thaxteriana, normally grown on egg yolk media. Egg yolk could be replaced by a sunflower oil-yeast extract mixture. E. thaxteriana was especially well studied. Various animal and vegetable fats and even chemically pure triglycerides could replace sunflower oil as a carbon source. Yeast extract was the best nitrogen source tested. In liquid culture, sporulation was directly dependent on yeast extract concentration. When yeast extract concentration was held constant, an increase in oil concentration did not produce an increase in sporulation. High dextrose concentrations inhibited resting spore formation. Liquid cultures of E. thaxteriana regularly produced 3 x 10(6) azygospores/ml in a 20 l fermentor.

Asunto(s)

RESUMEN

A comparative study was made of the production of extracellular proteolytic enzymes, which were originated from two different strains, one pathogenic and one saprophytic, of E. coronata in stable culture at 30 degrees C. Quantitative differences were found: the maximal activity of the three enzymes (collagenase, esterase, elastase) produced by the strain isolated from soil was always lower than that observed with the human strain.

Asunto(s)

RESUMEN

The results obtained in 15 years of research on the Entomophthorales pathogen of aphids showed the importance of the action of these fungi in the regulation of natural aphid populations and their possible use in agriculture as a biological control agent. Recent ecological studies on natural populations of aphids established the seasonal variation of the different fungal species and the diverse degrees of specificity between the species or groups of species of aphid and the various species of Entomophthora. The study of populations dynamics of an aphid species on a cultivated plant permitted the determination of the way a certain number of biotic and abiotic factors, such as temperature, humidity, thresholds of the insect population and of the infecting fungus lead to an epizootic development. If the air propagation of the disease by conidia is understood for a long time, the role of the soil as a reservoir for the infecting fungus has been demonstrated recently. Under favourable climatic conditions, the use of industrially produced resistant resting spores would allow the regulation of aphid populations in nature.

Asunto(s)

RESUMEN

A review was made about human entomophthoromycosis observed in tropical areas due to fungi of the order Entomophthorales. Rhinophycomycosis is caused by Entomophthora coronata, a cosmopolitan fungus which is only pathogen in wet tropical and subtropical climates. The disease, a muco-cutaneous infection of the face, induces monstruous deformations. Basidiobolomycosis is caused by Basidiobolus meristosporus, a saprophyte of different amphibians and reptiles very often present in the family Agamidae. The disease interests the subcutaneous tissues and is mainly located at the trunk, shoulders and upper part of the limbs. The epidemiology, clinic and therapeutic were reported. Histopathological lesions and morphology of both fungi were studied. The etiology of the casual agents of these mycoses was discussed.

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)