Mulching with coffee husk and pulp in strawberry affects edaphic predatory mite and spider mite densities.

Mulching of soil beds of strawberry fields is usually done with polyethylene film in southern Minas Gerais state, Brazil. This material is relatively expensive and difficult to discard after use. In some countries, mulching is done with the use of organic material that could have an advantage over the use of plastic for its easier degradation after use, and for favoring edaphic beneficial organisms. Predatory mites (especially Gamasina, Mesostigmata) may be abundant in the soil and could conceivably move to the soil surface and onto the short-growing strawberry plants at night, helping in the control or pest arthropods. The two-spotted spider mite, Tetranychus urticae Koch, is considered an important strawberry pest in that region, where the fungus Neozygites floridana (Weiser and Muma) has been found to infect it. Different mulching types could affect the incidence of this pathogen. Dehydrated coffee husk and pulp (DCHP) is a byproduct readily available in southern Minas Gerais, where could be used as organic mulching in strawberry beds. The temporary contact of that material with the soil of a patch of natural vegetation could facilitate its colonization by edaphic predatory mites helpful in the control of strawberry pests. The objective of this work was to study the effect of mulching type on the population dynamics of the two-spotted spider mite, associate mites and N. floridana, in a greenhouse and in the field. The use of DCHP increased the number of edaphic Gamasina on strawberry plants-Proctolaelaps pygmaeus (Müller) (Melicharidae) and Blattisocius dentriticus (Berlese) (Blattisociidae) were observed on strawberry leaflets, mainly in nocturnal samplings, indicating their possible daily migration from soil to plants. Lower levels of two-spotted spider mite occurred on plants from pots or soil beds mulched with DCHP instead of polyethylene film, possibly because of the slightly higher levels of mites of the family Phytoseiidae and infection by N. floridana. Adding DCHP onto the floor of natural vegetation did not result in higher diversity or levels of gamasine mites on DCHP. Complementary studies should be conducted to find ways to increase diversity and density of those organisms in strawberry beds, in an attempt to improve biological control of strawberry pests. The decision to use DCHP for mulching should also take into account other factors such as strawberry yield, costs and efficiency of weed management, to be evaluated in subsequent studies.

Alkane-grown Beauveria bassiana produce mycelial pellets displaying peroxisome proliferation, oxidative stress, and cell surface alterations.

The entomopathogenic fungus Beauveria bassiana is able to grow on insect cuticle hydrocarbons, inducing alkane assimilation pathways and concomitantly increasing virulence against insect hosts. In this study, we describe some physiological and molecular processes implicated in growth, nutritional stress response, and cellular alterations found in alkane-grown fungi. The fungal cytology was investigated using light and transmission electron microscopy while the surface topography was examined using atomic force microscopy. Additionally, the expression pattern of several genes associated with oxidative stress, peroxisome biogenesis, and hydrophobicity were analysed by qPCR. We found a novel type of growth in alkane-cultured B. bassiana similar to mycelial pellets described in other alkane-free fungi, which were able to produce viable conidia and to be pathogenic against larvae of the beetles Tenebrio molitor and Tribolium castaneum. Mycelial pellets were formed by hyphae cumulates with high peroxidase activity, exhibiting peroxisome proliferation and an apparent surface thickening. Alkane-grown conidia appeared to be more hydrophobic and cell surfaces displayed different topography than glucose-grown cells. We also found a significant induction in several genes encoding for peroxins, catalases, superoxide dismutases, and hydrophobins. These results show that both morphological and metabolic changes are triggered in mycelial pellets derived from alkane-grown B. bassiana.

The Xenon Test Chamber Q-SUN® for testing realistic tolerances of fungi exposed to simulated full spectrum solar radiation.

The low survival of insect-pathogenic fungi when used for insect control in agriculture is mainly due to the deleterious effects of ultraviolet radiation and heat from solar irradiation. In this study, conidia of 15 species of entomopathogenic fungi were exposed to simulated full-spectrum solar radiation emitted by a Xenon Test Chamber Q-SUN XE-3-HC 340S (Q-LAB® Corporation, Westlake, OH, USA), which very closely simulates full-spectrum solar radiation. A dendrogram obtained from cluster analyses, based on lethal time 50 % and 90 % calculated by Probit analyses, separated the fungi into three clusters: cluster 3 contains species with highest tolerance to simulated full-spectrum solar radiation, included Metarhizium acridum, Cladosporium herbarum, and Trichothecium roseum with LT50 > 200 min irradiation. Cluster 2 contains eight species with moderate UV tolerance: Aschersonia aleyrodis, Isaria fumosorosea, Mariannaea pruinosa, Metarhizium anisopliae, Metarhizium brunneum, Metarhizium robertsii, Simplicillium lanosoniveum, and Torrubiella homopterorum with LT50 between 120 and 150 min irradiation. The four species in cluster 1 had the lowest UV tolerance: Lecanicillium aphanocladii, Beauveria bassiana, Tolypocladium cylindrosporum, and Tolypocladium inflatum with LT50 < 120 min irradiation. The QSUN Xenon Test Chamber XE3 is often used by the pharmaceutical and automotive industry to test light stability and weathering, respectively, but it was never used to evaluate fungal tolerance to full-spectrum solar radiation before. We conclude that the equipment provided an excellent tool for testing realistic tolerances of fungi to full-spectrum solar radiation of microbial agents for insect biological control in agriculture.

Responses of entomopathogenic fungi to the mutagen 4-nitroquinoline 1-oxide.

Survival of entomopathogenic fungi under solar ultraviolet (UV) radiation is paramount to the success of biological control of insect pests and disease vectors. The mutagenic compound 4-nitroquinoline 1-oxide (4-NQO) is often used to mimic the biological effects of UV radiation on organisms. Therefore, we asked whether tolerance to 4-NQO could predict tolerance to UV radiation in thirty isolates of entomopathogenic fungi and one isolate of a xerophilic fungus. A dendrogram obtained from cluster analyses based on the 50 and 90 % inhibitory concentrations (IC50 and IC90, respectively) divided the fungal isolates into six clusters numbered consecutively based on their tolerance to 4-NQO. Cluster 6 contained species with highest tolerance to 4-NQO (IC50 > 4.7 µM), including Mariannaea pruinosa, Lecanicillium aphanocladii, and Torrubiella homopterorum. Cluster 1 contained species least tolerant to 4-NQO (IC50 < 0.2 µM), such as Metarhizium acridum (ARSEF 324), Tolypocladium geodes, and Metarhizium brunneum (ARSEF 7711). With few exceptions, the majority of Metarhizium species showed moderate to low tolerances (IC50 between 0.4 and 0.9 µM) and were placed in cluster 2. Cluster 3 included species with moderate tolerance (IC50 between 1.0 and 1.2 µM). In cluster 4 were species with moderate to high tolerance (IC50 between 1.3 and 1.6 µM). Cluster 5 contained the species with high tolerance (IC50 between 1.9 and 4.0 µM). The most UV tolerant isolate of M. acridum, ARSEF 324, was the least tolerant to 4-NQO. Also, L. aphanocladii, which is very susceptible to UV radiation, showed high tolerance to 4-NQO. Our results indicate that tolerance to 4-NQO does not correlate with tolerance to UV radiation. Therefore this chemical compound is not a predictor of UV tolerance in entomopathogenic fungi.

Zoophthora radicans (Entomophthorales), a fungal pathogen of Bagrada hilaris and Bactericera cockerelli (Hemiptera: Pentatomidae and Triozidae): Prevalence, pathogenicity, and interplay of environmental influence, morphology, and sequence data on fungal identification.

The exotic bagrada bug or painted bug, Bagrada hilaris, and the native potato/tomato psyllid, Bactericera (=Paratrioza) cockerelli, are key pests of horticulture in western North America. In 2014-2015, adult and juvenile B. hilaris and B. cockerelli killed by fungi in the genus Zoophthora were detected near Saltillo, northeastern Mexico. We report the field prevalence and observations of Zoophthora on these hosts. The morphology and growth characteristics of field-collected specimens and pure in vitro cultures, as well as molecular markers (ITS1 and ITS4) were analyzed to identify these Zoophthora populations. Although there were morphological spore differences detected among field collections from both insect hosts, the fungi causing these mycoses can be identified as the same species (Zoophthora radicans), according to morphometric data from in vitro cultures (where differences observed in field material were attenuated) and sequence data (96-99% identity for ITS1 and 4). These results underscore the plasticity of field collections and in vitro cultures, and the relevance of comprehensive morphological and molecular analysis from cultures under standard conditions. Dose-response bioassays were conducted with one Z. radicans strain against bagrada bug nymphs. Exposure to conidial showers from cultures induced 30-90% mortality. This is the first report of a natural enemy of bagrada bug in Mexico, and the first published report of entomophthoralean fungi naturally attacking bagrada bugs and potato psyllids. Z. radicans should be further investigated as a tool in the biological control of hemipterans.

Fine-scale spatial genetic structure of a fungal parasite of coffee scale insects.

The entomopathogenic fungus Lecanicillium lecanii persists in a highly dynamic network of habitat patches (i.e., a metapopulation) formed by its primary host, the green coffee scale Coccus viridis. Lecanicillium lecanii is an important biological control of both C. viridis and the coffee rust, Hemileia vastatrix. Successfully managing this biocontrol agent will depend on an increased understanding of the characteristics of its dispersal, as migration between occupied and unoccupied patches is essential for the persistence of this metapopulation. In the present study, we employ a population genetics approach, and show that in our study system, a coffee farm in the Soconusco region of southern Mexico, L. lecanii is characterized by clear spatial genetic structure among plots within the farm but a lack of apparent structure at smaller scales. This is consistent with dispersal dominated by highly localized transport, such as by insects or rain splash, and less dependence on longer distance dispersal such as wind transport. The study site was dominated by a few multi-locus microsatellite genotypes, and their identities and large-scale locations persist across both study years, suggesting that local epizootics (outbreaks) are initiated each wet season by residual propagules from the previous wet season, and not by long-distance transport of propagules from other sites. The index of association, a measure of linkage disequilibrium, indicates that epizootics are primarily driven by asexual, clonal reproduction, which is consistent with the apparent lack of a teleomorph in the study site and the presence of only a single mating type across the site (MAT-1-2-1). Although the same predominant clonal genotypes were found across years, a drastic difference in genotypic diversity was witnessed across two sites between the two years, suggesting that interclonal selection was occurring. In light of the dispersal limitation of L. lecanii, spatial structure may be an essential axis of management to ensure the persistence of L. lecanii and preserve the ecosystem services provided by this versatile biocontrol agent in this and similar coffee farms.

Pandora bullata (Entomophthoromycota: Entomophthorales) affecting calliphorid flies in central Brazil.

Fungi are where one finds them, and if one seeks fungal pathogens affecting flies, then a garbage dump may be an ideal place to find both persistent, abundant fly populations and their fungal pathogens. An obvious fungal epizootic affecting the oriental latrine fly, Chrysomya megacephala (Diptera: Calliphoridae), was observed over several days in mid-February 2015 at the local garbage dump adjacent to the city of Cavalcante, northern Goiás. This site harbored large populations of both C. megacephala and a Musca sp. (Diptera: Muscidae) but only the population of oriental latrine fly was affected by any fungal pathogen and presented unusually dense populations of fresh cadavers. The fungus was identifiable as Pandora bullata (Entomophthorales: Entomophthoraceae) only after a very small number of characteristically decorated resting spores were found in these flies two months later; this represents the first Brazilian (and South American) record of this species. P. bullata is known previously from a small number of North American, European and Australian collections, all of which have included relatively abundant production of resting spores. We cannot dismiss the possibility that the extremely sparse formation of resting spores at this Brazilian site may be due to abiotic factors such as latitude (13°46'40.53″S), day length, ambient temperatures, or even the precipitation patterns in this mid-tropical montaine site. Epizootic events affecting calliphorids in Brazil strengthen the interest in entomophthoran pathogens for biological control of flies.

Selection of reference genes for expression analysis in the entomophthoralean fungus Pandora neoaphidis

Abstract The selection of suitable reference genes is crucial for accurate quantification of gene expression and can add to our understanding of host–pathogen interactions. To identify suitable reference genes in Pandora neoaphidis, an obligate aphid pathogenic fungus, the expression of three traditional candidate genes including 18S rRNA(18S), 28S rRNA(28S) and elongation factor 1 alpha-like protein (EF1), were measured by quantitative polymerase chain reaction at different developmental stages (conidia, conidia with germ tubes, short hyphae and elongated hyphae), and under different nutritional conditions. We calculated the expression stability of candidate reference genes using four algorithms including geNorm, NormFinder, BestKeeper and Delta Ct. The analysis results revealed that the comprehensive ranking of candidate reference genes from the most stable to the least stable was 18S (1.189), 28S (1.414) and EF1 (3). The 18S was, therefore, the most suitable reference gene for real-time RT-PCR analysis of gene expression under all conditions. These results will support further studies on gene expression in P. neoaphidis.

Selection of reference genes for expression analysis in the entomophthoralean fungus Pandora neoaphidis.

The selection of suitable reference genes is crucial for accurate quantification of gene expression and can add to our understanding of host-pathogen interactions. To identify suitable reference genes in Pandora neoaphidis, an obligate aphid pathogenic fungus, the expression of three traditional candidate genes including 18S rRNA(18S), 28S rRNA(28S) and elongation factor 1 alpha-like protein (EF1), were measured by quantitative polymerase chain reaction at different developmental stages (conidia, conidia with germ tubes, short hyphae and elongated hyphae), and under different nutritional conditions. We calculated the expression stability of candidate reference genes using four algorithms including geNorm, NormFinder, BestKeeper and Delta Ct. The analysis results revealed that the comprehensive ranking of candidate reference genes from the most stable to the least stable was 18S (1.189), 28S (1.414) and EF1 (3). The 18S was, therefore, the most suitable reference gene for real-time RT-PCR analysis of gene expression under all conditions. These results will support further studies on gene expression in P. neoaphidis.

Selection of reference genes for expression analysis in the entomophthoralean fungus Pandora neoaphidis

The selection of suitable reference genes is crucial for accurate quantification of gene expression and can add to our understanding of hostpathogen interactions. To identify suitable reference genes in Pandora neoaphidis, an obligate aphid pathogenic fungus, the expression of three traditional candidate genes including 18S rRNA(18S), 28S rRNA(28S) and elongation factor 1 alpha-like protein (EF1), were measured by quantitative polymerase chain reaction at different developmental stages (conidia, conidia with germ tubes, short hyphae and elongated hyphae), and under different nutritional conditions. We calculated the expression stability of candidate reference genes using four algorithms including geNorm, NormFinder, BestKeeper and Delta Ct. The analysis results revealed that the comprehensive ranking of candidate reference genes from the most stable to the least stable was 18S (1.189), 28S (1.414) and EF1 (3). The 18S was, therefore, the most suitable reference gene for real-time RT-PCR analysis of gene expression under all conditions. These results will support further studies on gene expression in P. neoaphidis. (AU)

Prevalence of entomophthoralean fungi (Entomophthoromycota) of aphids in relation to developmental stages.

BACKGROUND: Transmission of fungal pathogens of aphids may be affected by the host developmental stage. Brassica and Lactuca sativa L. crops were sampled in Santa Fe, Argentina, to determine the prevalence of fungal-diseased aphids and investigate the differences between developmental stages of aphids. RESULTS: The fungal pathogens identified were Zoophthora radicans (Bref.) A. Batko, Pandora neoaphidis (Remaud. & Hennebert) Humber and Entomophthora planchoniana Cornu. Their prevalence on each crop was calculated. The numbers of infected aphids were significantly different between the different developmental stages on all crops except B. oleracea var. botrytis L. CONCLUSIONS: The entomophthoralean fungi identified are important mortality factors of aphids on horticultural crops in Santa Fe. The numbers of infected nymphs and adults were significantly different, nymphs being the most affected developmental stage. © 2015 Society of Chemical Industry.

The effect of synthetic pesticides and sulfur used in conventional and organically grown strawberry and soybean on Neozygites floridana, a natural enemy of spider mites.

BACKGROUND: The beneficial fungus Neozygites floridana kills the two-spotted spider mite Tetranychus urticae, which is a serious polyphagous plant pest worldwide. Outbreaks of spider mites in strawberry and soybean have been associated with pesticide applications. Pesticides may affect N. floridana and consequently the natural control of T. urticae. N. floridana is a fungus difficult to grow in artificial media, and for this reason, very few studies have been conducted with this fungus, especially regarding the impact of pesticides. The aim of this study was to conduct a laboratory experiment to evaluate the effect of pesticides used in strawberry and soybean crops on N. floridana. RESULTS: Among the pesticides used in strawberry, the fungicides sulfur and cyprodinil + fludioxonil completely inhibited both the sporulation and conidial germination of N. floridana. The fungicide fluazinam affected N. floridana drastically. The application of the fungicide tebuconazole and the insecticides fenpropathrin and abamectin resulted in a less pronounced negative effect on N. floridana. Except for epoxiconazole and cyproconazole, all tested fungicides used in soybean resulted in a complete inhibition of N. floridana. Among the three insecticides used in soybean, lambda-cyhalothrin and deltamethrin resulted in a significant inhibition of N. floridana. CONCLUSION: The insecticides/ acaricides abamectin and lambda-cyhalothrin at half concentrations and fenpropathrin and permethrin and the fungicide tebuconazole at the recommended concentrations resulted in the lowest impact on N. floridana. The fungicides with the active ingredients sulfur, cyprodinil + fludioxonil, azoxystrobin, azoxystrobin + cyproconazole, trifloxystrobin + tebuconazole and pyraclostrobin + epoxiconazole negatively affected N. floridana. © 2015 Society of Chemical Industry.

Cryptococcus: isolamento ambiental e caracterização bioquímica / Cryptococcus: environmental isolation and biochemical characterization

O gênero Cryptococcus caracteriza-se por ser uma levedura responsável por infecção sistêmica, causada pelas espécies Cryptococcus neoformans e Cryptococcus gattii. O fungo é encontrado em substratos de origem animal e vegetal, e a infecção ocorre com a inalação de basidiósporos ou leveduras desidratadas infectantes presentes no ambiente. O presente trabalho teve por objetivo pesquisar a existência de microfocos de Cryptococcussp.em amostras ambientais da cidade de Araçatuba, São Paulo, com a finalidade de minimizar os riscos de contaminação do homem e dos animais, buscando o conhecimento da ecoepidemiologia do Cryptococcus. Foram colhidas 50 amostras oriundas de ocos e troncos de árvores (Cassiasp., Ficussp., Caesalpinea peltophorides) de 10 locais representativos do perímetro urbano, as quais foram encaminhadas ao Laboratório de Bacteriologia e Micologia da Faculdade de Medicina Veterinária de Araçatuba-Unesp, onde foram processadas e semeadas em placas de Petri contendo ágar semente de Níger e Sabouraud dextrose com clorafenicol e incubadas à temperatura de 30ºC, por um período não inferior a cinco dias. Posteriormente, foram submetidas às provas bioquímicas: produção de urease, termotolerância a 37ºC e quimiotipagem em ágar CGB (L-canavanina-glicina-azul de bromotimol). A análise dos resultados revelaram que 17 (34%) dos cultivos foram positivos para o gênero Cryptococcus, sendo nove (18%) para Cryptococcus gattiie oito (16%) para Cryptococcus neoformans. Outras leveduras correlacionadas, como Rhodotorula sp. e Candida sp., também foram isoladas. Conclui-se que os basidiósporos de Cryptococcusencontram-se dispersos na natureza, constituindo microfocos ambientais, não vinculados necessariamente a um único hospedeiro.(AU)

Cryptococcosis is an opportunistic fungal infection caused by Cryptococcusyeasts, especially C. neoformans and Cryptococcus gattii. The fungus is found in substrates of animal and vegetable origin, and infection occurs through inhalation and seedlings present in the environment. The present study aimed to investigate the existence of microfocus Cryptococcus sp. from the environmental samples of Araçatuba city, São Paulo, featuring new niches, by decoupling the direct relationship between fungus and host in order to minimize the risk of contamination of man and animals, understanding the ecoepidemiology of Cryptococcus. Fifty samples from hollows and tree trunks were harvested (Cassia sp., Ficus sp., Caesalpinea peltophorides) from ten representatives in the urban perimeter. The samples were immediately sent to the Laboratory of Bacteriology and Mycology, Faculty of Veterinary Medicine Araçatuba - Unesp where they were processed and plated on Petri dishes containing agar seed Niger and Sabouraud dextrose agar with chloramphenicol, incubated at 30ºC for a period of no less than 5 days. Afterwards they were subimitted to biochemical tests: urease production, thermotolerance at 37°C and quimiotipagem in CGB agar (L- Canavanine-Glycine-Bromothymol blue). The results showed that 17 (34%) cultures were positive for Cryptococcus, 9 (18%) for Cryptococcus gattii and 8 (16%) for Cryptococcus neoformans. Other yeast correlated as Rhodotorula sp. and Candida sp. were isolated. We conclude that the infectious propagules of Cryptococcus are dispersed in nature and constitute an environmental microfocus, not necessarily being bound to a single host.(AU)

Cryptococcus: isolamento ambiental e caracterização bioquímica / Cryptococcus: environmental isolation and biochemical characterization

O gênero Cryptococcus caracteriza-se por ser uma levedura responsável por infecção sistêmica, causada pelas espécies Cryptococcus neoformans e Cryptococcus gattii. O fungo é encontrado em substratos de origem animal e vegetal, e a infecção ocorre com a inalação de basidiósporos ou leveduras desidratadas infectantes presentes no ambiente. O presente trabalho teve por objetivo pesquisar a existência de microfocos de Cryptococcussp.em amostras ambientais da cidade de Araçatuba, São Paulo, com a finalidade de minimizar os riscos de contaminação do homem e dos animais, buscando o conhecimento da ecoepidemiologia do Cryptococcus. Foram colhidas 50 amostras oriundas de ocos e troncos de árvores (Cassiasp., Ficussp., Caesalpinea peltophorides) de 10 locais representativos do perímetro urbano, as quais foram encaminhadas ao Laboratório de Bacteriologia e Micologia da Faculdade de Medicina Veterinária de Araçatuba-Unesp, onde foram processadas e semeadas em placas de Petri contendo ágar semente de Níger e Sabouraud dextrose com clorafenicol e incubadas à temperatura de 30ºC, por um período não inferior a cinco dias. Posteriormente, foram submetidas às provas bioquímicas: produção de urease, termotolerância a 37ºC e quimiotipagem em ágar CGB (L-canavanina-glicina-azul de bromotimol). A análise dos resultados revelaram que 17 (34%) dos cultivos foram positivos para o gênero Cryptococcus, sendo nove (18%) para Cryptococcus gattiie oito (16%) para Cryptococcus neoformans. Outras leveduras correlacionadas, como Rhodotorula sp. e Candida sp., também foram isoladas. Conclui-se que os basidiósporos de Cryptococcusencontram-se dispersos na natureza, constituindo microfocos ambientais, não vinculados necessariamente a um único hospedeiro.

Cryptococcosis is an opportunistic fungal infection caused by Cryptococcusyeasts, especially C. neoformans and Cryptococcus gattii. The fungus is found in substrates of animal and vegetable origin, and infection occurs through inhalation and seedlings present in the environment. The present study aimed to investigate the existence of microfocus Cryptococcus sp. from the environmental samples of Araçatuba city, São Paulo, featuring new niches, by decoupling the direct relationship between fungus and host in order to minimize the risk of contamination of man and animals, understanding the ecoepidemiology of Cryptococcus. Fifty samples from hollows and tree trunks were harvested (Cassia sp., Ficus sp., Caesalpinea peltophorides) from ten representatives in the urban perimeter. The samples were immediately sent to the Laboratory of Bacteriology and Mycology, Faculty of Veterinary Medicine Araçatuba - Unesp where they were processed and plated on Petri dishes containing agar seed Niger and Sabouraud dextrose agar with chloramphenicol, incubated at 30ºC for a period of no less than 5 days. Afterwards they were subimitted to biochemical tests: urease production, thermotolerance at 37°C and quimiotipagem in CGB agar (L- Canavanine-Glycine-Bromothymol blue). The results showed that 17 (34%) cultures were positive for Cryptococcus, 9 (18%) for Cryptococcus gattii and 8 (16%) for Cryptococcus neoformans. Other yeast correlated as Rhodotorula sp. and Candida sp. were isolated. We conclude that the infectious propagules of Cryptococcus are dispersed in nature and constitute an environmental microfocus, not necessarily being bound to a single host.

Two-spotted spider mite and its natural enemies on strawberry grown as protected and unprotected crops in Norway and Brazil.

Cultivation of strawberry in plastic tunnels has increased considerably in Norway and in southeastern Brazil, mainly in an attempt to protect the crop from unsuitable climatic factors and some diseases as well as to allow growers to expand the traditional production season. It has been hypothesized that cultivation under tunnels could increase the incidence of one of its major pests in many countries where strawberry is cultivated, including Norway and Brazil, the two spotted spider mite, Tetranychus urticae. The objective of this study was to evaluate the effect of the use of tunnels on the incidence of T. urticae and on its natural enemies on strawberry in two ecologically contrasting regions, Norway (temperate) and southeastern Brazil (subtropical). In both countries, peak densities of T. urticae in tunnels and in the open fields were lower than economic thresholds reported in the literature. Factors determining that systematically seem to be the prevailing relatively low temperature in Norway and high relative humidity in both countries. The levels of occurrence in Norway and Brazil in 2010 were so low that regardless of any potential effect of the use of tunnel, no major differences were observed between the two cropping systems in relation to T. urticae densities. In 2009 in Norway and in 2011 in Brazil, increase in T. urticae population seemed to have been restrained mainly by rainfall in the open field and by predatory mites in the tunnels. Phytoseiids were the most numerous predatory mite group of natural occurrence on strawberry, and the prevalence was higher in Brazil, where the most abundant species on strawberry leaves were Neoseiulus anonymus and Phytoseiulus macropilis. In Norway, the most abundant naturally occurring phytoseiids on strawberry leaves were Typhlodromus (Anthoseius) rhenanus and Typhlodromus (Typhlodromus) pyri. Predatory mites were very rare in the litter samples collected in Norway. Infection rate of the pest by the fungus Neozygites floridana (Neozygitaceae) was low. The results of this work suggest that in Norway the use of tunnels might not affect the population densities of T. urticae on strawberry in years of lower temperatures. When temperature is not a limiting factor for the development of T. urticae in that country (apparently always the case in southern Brazil), strawberry cultivation in the tunnels may allow T. urticae to reach higher population levels than in open fields (because of the provided protection from the direct impact of rainfall), but natural enemies may prevent higher levels from being reached.

Confirmation of Neozygites floridana azygospore formation in two-spotted spider mite (Tetranychus urticae) in strains from tropical and temperate regions.

Neozygites floridana is an obligate fungal pathogen of mites in the family Tetranychidae and is an important natural enemy of the two-spotted spider mite (Tetranychus urticae). Until now, information about the formation of azygospores remained to be fully confirmed. In this study, we document the formation of azygospores by a Brazilian N. floridana strain and the formation of azygospores and zygospores by a Norwegian N. floridana strain, both in the host T. urticae. Evidence of both zygosporogenesis and azygosporogenesis was also found in the same individual in the Norwegian stains. Further we report the presence of immature azygospores with 1-3 nuclei for the Norwegian strains, immature resting spores (probably azygospores) with 1-8 nuclei for the Brazilian strain, and mature resting spores with 2 nuclei for both the Norwegian and the Brazilian strains (azygo- or zygospores). Our observations suggest that the immature resting spore (prespore) of both strains begins in a multinucleate condition but that the nuclear number is reduced during maturation until mature resting spore is binucleate regardless of its origin as a zygospore or azygospore.

Natural occurrence of entomophthoroid fungi of aphid pests on Medicago sativa L. in Argentina.

Four species of entomophthoroid fungi, Pandora neoaphidis (Entomophthorales: Entomophthoraceae), Zoophthora radicans (Entomophthorales: Entomophthoraceae), Entomophthora planchoniana (Entomophthorales: Entomophthoraceae) and Neozygites fresenii (Neozygitales: Neozygitaceae) were found to infect Aphis craccivora, Therioaphis trifolii, and Acyrthosiphon pisum and unidentified species of Acyrthosiphon on lucerne in Argentina. Samples were collected from five sites (Ceres, Rafaela, Sarmiento, Monte Vera and Bernardo de Irigoyen) in the province of Santa Fe. In this study, Zoophthora radicans was the most important pathogen and was recorded mainly on Acyrthosiphon sp. Zoophthora radicans was successfully isolated and maintained in pure cultures. This study is the first report of entomophthoroid fungi infecting lucerne (Medicago sativa L.) aphids in Argentina.

Ocurrencia natural de hongos entomophthorales de áfidos plaga de Medicago sativa L. en Argentina / Natural occurrence of entomophthoroid fungi of aphid pests on Medicago sativa L. in Argentina

Se encontraron cuatro especies de hongos Entomophthorales, Pandora neoaphidis, Zoophthora radicans, Entomophthora planchoniana (Entomophthorales: Entomophthoraceae) y Neozygites fresenii (Neozygitales: Neozygitaceae) infectando a Aphis craccivora, Therioaphis trifolii, Acyrthosiphon pisum y a especies no identificadas pertenecientes al género Acyrthosiphon en cultivos de alfalfa (Medicago sativa L.), en la Argentina. Los muestreos fueron realizados en cinco sitios (Ceres, Rafaela, Sarmiento, Monte Vera y Bernardo de Irigoyen) de la provincia de Santa Fe. Zoophthora radicans fue el patógeno más importante registrado principalmente en Acyrthosiphon sp. Zoophthora radicans fue exitosamente aislado y mantenido en cultivos puros. Este estudio documenta por primera vez en la Argentina la presencia de hongos Entomophthorales infectando áfidos en alfalfa

Four species of entomophthoroid fungi, Pandora neoaphidis (Entomophthorales: Entomophthoraceae), Zoophthora radicans (Entomophthorales: Entomophthoraceae), Entomophthora planchoniana (Entomophthorales: Entomophthoraceae) and Neozygites fresenii (Neozygitales: Neozygitaceae) were found to infect Aphis craccivora, Therioaphis trifolii, and Acyrthosiphon pisum and unidentified species of Acyrthosiphon on lucerne in Argentina. Samples were collected from five sites (Ceres, Rafaela, Sarmiento, Monte Vera and Bernardo de Irigoyen) in the province of Santa Fe. In this study, Zoophthora radicans was the most important pathogen and was recorded mainly on Acyrthosiphon sp. Zoophthora radicans was successfully isolated and maintained in pure cultures. This study is the first report of entomophthoroid fungi infecting lucerne (Medicago sativa L.) aphids in Argentina

Natural occurrence of entomophthoroid fungi of aphid pests on Medicago sativa L. in Argentina. / Natural occurrence of entomophthoroid fungi of aphid pests on Medicago sativa L. in Argentina.

Four species of entomophthoroid fungi, Pandora neoaphidis (Entomophthorales: Entomophthoraceae), Zoophthora radicans (Entomophthorales: Entomophthoraceae), Entomophthora planchoniana (Entomophthorales: Entomophthoraceae) and Neozygites fresenii (Neozygitales: Neozygitaceae) were found to infect Aphis craccivora, Therioaphis trifolii, and Acyrthosiphon pisum and unidentified species of Acyrthosiphon on lucerne in Argentina. Samples were collected from five sites (Ceres, Rafaela, Sarmiento, Monte Vera and Bernardo de Irigoyen) in the province of Santa Fe. In this study, Zoophthora radicans was the most important pathogen and was recorded mainly on Acyrthosiphon sp. Zoophthora radicans was successfully isolated and maintained in pure cultures. This study is the first report of entomophthoroid fungi infecting lucerne (Medicago sativa L.) aphids in Argentina.