&lt;b&gt;Population density of &lt;i&gt;Beauveria bassiana&lt;/i&gt; in soil under the action of fungicides and native microbial populations

Soares, Flávia Barbosa; Monteiro, Ana Ruth Macêdo; Barbosa, José Carlos; Mochi, Dinalva Alves

doi:10.4025/actasciagron.v39i4.32816

Cited by 6 publications

(4 citation statements)

References 26 publications

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“…This index classifies chemical compounds according to their toxic effects on fungi cultured in vitro on a solid‐poisoned medium (Silva, Quintela, Mascarin, Barrigossi, & Lião, ). The BIs were calculated using the B. bassiana colony mean vegetative growth (VG), sporulation (SP) and conidia germination (GR) percentages, as compared with the controls (Soares, Monteiro, Babosa, & Mochi, ), as follows:

BI = \frac{47 [VG] + 43 [SP] + 10 [GR]}{100}

where the BI defines the level of fungicide toxicity against the entomopathogenic fungus ( B. bassiana ) in vitro, and GR, VG and SP are the proportions of conidia germination, fungus vegetative growth and conidia numbers, respectively, of the fungicide treatments compared with the controls. The classification of the BI in terms of the effects of the chemical products on a fungus was: 0–41, toxic (T); 42–66, moderately toxic (MT) and >66, compatible (C).…”

Section: Methodsmentioning

confidence: 99%

In vitro compatibility of Beauveria bassiana strain ATCC 74040 with copper fungicides

Celar

Kos

2020

J Applied Entomology

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Copper fungicides and mycoinsecticides based on entomopathogenic fungi Beauveria spp. are the most common pesticides used in organic crop production systems. The in vitro effects of the copper fungicides copper oxide, copper hydroxide, copper oxychloride, copper sulphate, dicopper chloride trihydroxide and tribasic copper sulphate were investigated for mycelial growth, sporulation and conidial germination of the ATCC 74040 commercial strain of Beauveria bassiana. Mycelial growth was evaluated on potato dextrose agar plates with 100%, 75%, 50%, 25%, 12.5%, 6.25% and 0% of the recommended application rates of each fungicide at 15 and 25°C. Sporulation and conidial germination were determined at the recommended field doses of each fungicide at 25°C. All copper fungicides had fungistatic or fungicidal effects on B. bassiana that varied according to the dose. Only in two cases, copper oxide at 15°C and copper hydroxide at 25°C, at the lowest concentration of 6.5%, was mycelial growth not statistically significantly inhibited. Inhibition of mycelial growth depended both on the fungicide and its concentration, and partly on temperature. Both sporulation and conidial germination of B. bassiana were significantly inhibited by all fungicides. All fungicides inhibited the sporulation in a similar way (99.8%–100%). With the exception of copper oxychloride (inhibition, 13.6%), the other fungicides showed high detrimental effects on conidial germination (inhibition, 91.7%–100%). The fungus was strongly affected by some fungicides even at the lowest doses. The biological index used for the B. bassiana with copper fungicides ranged from 0.6 (copper sulphate) to 18.1 (copper oxychloride). Therefore, the tested fungicides were classified into the upper half of the highly toxic (T) category and are considered incompatible with the entomopathogenic fungus B. bassiana strain ATCC 74040 under in vivo experimental conditions. These results need to be further verified in vitro under both greenhouse and open‐field conditions.

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BI = \frac{47 [VG] + 43 [SP] + 10 [GR]}{100}

Section: Methodsmentioning

confidence: 99%

In vitro compatibility of Beauveria bassiana strain ATCC 74040 with copper fungicides

Celar

Kos

2020

J Applied Entomology

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“…Actinobacteria with antifungal activity are reported to show high species richness in certain types of soil [27][28][29]. Because entomopathogenic fungi are also widely distributed in soil [30][31][32][33], we hypothesize that some soil-dwelling insects may choose soil types with the highest abundance of actinobacteria for nest building to avoid being infected by some soil-derived entomopathogenic fungi.…”

Section: Plos Pathogensmentioning

confidence: 96%

The nesting preference of an invasive ant is associated with the cues produced by actinobacteria in soil

et al. 2020

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Soil-dwelling animals are at risk of pathogen infection in soils. When choosing nesting sites, animals could reduce this risk by avoiding contact with pathogens, yet there is currently little evidence. We tested this hypothesis using Solenopsis invicta as a model system. Newly mated queens of S. invicta were found to nest preferentially in soil containing more actinobacteria of Streptomyces and Nocardiopsis and to be attracted to two volatiles produced by these bacteria, geosmin and 2-methylisoborneol. Actinobacteria-rich soil was favored by S. invicta and this soil contained fewer putative entomopathogenic fungi than adjacent areas. Queens in such soil benefited from a higher survival rate. In culture, isolated actinobacteria inhibited entomopathogenic fungi, suggested that their presence may reduce the risk of fungal infection. These results indicated a soil-dwelling ant may choose nest sites presenting relatively low pathogen risk by detecting the odors produced by bacteria with anti-fungal properties.

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“…Pohlan et al [ 62 ] showed that cover crops can reduce CBB populations, since they provide habitats for natural enemies. This hypothesis could explain why there were more CBB, and therefore associated BB, under conventional treatments, whereas the contrary could have been expected [ 63 ]. Moreover, cultivation generally does not seem to affect the level of the presence of BB in soils, whether natural or cultivated [ 64 ].…”

Section: Discussionmentioning

confidence: 99%

Organic Farming Practices and Shade Trees Reduce Pest Infestations in Robusta Coffee Systems in Amazonia

Piato

Subía

Pico

et al. 2021

Life

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Coffee agroforestry systems could reconcile agricultural and environmental objectives. While pests and diseases can reduce yield, their interactions with shade and nutrition have been rarely researched, and are particularly lacking in perennial systems. We hypothesized that intermediate shade levels could reduce coffee pests while excess shade could favor fungal diseases. We hypothesized that organic rather than mineral fertilization would better synchronize with nutrient uptake and higher nutrient inputs would be associated with reduced pest and disease damage due to higher plant vigor, yet effects would be less obvious in shaded plots as coffee growth would be light-limited. Using three-year-old trees of Coffea canephora var. Robusta (robusta coffee) in the Ecuadorian Amazon, we compared a full-sun system with four shading methods creating different shade levels: (1) Myroxylon balsamum; (2) Inga edulis; (3) Erythrina spp.; or, (4) Erythrina spp. plus Myroxylon balsamum. Conventional farming at either (1) moderate or (2) intensified input and organic farming at (3) low or (4) intensified input were compared in a split-plot design with shade as the main plot factor and farming practice as the sub-plot factor. The infestation of the following pests and disease incidences were evaluated monthly during the dry season: brown twig beetle (Xylosandrus morigerus), coffee leaf miner (Leucoptera coffeella), coffee berry borer (Hypothenemus hampei), anthracnose disease (Colletotrichum spp.), thread blight (Pellicularia koleroga), and cercospora leaf spot (Cercospora coffeicola). Coffee berry borer and brown twig beetle infestation were both reduced by 7% in intensified organic treatments compared to intensified conventional treatments. Colonization of coffee berry borer holes in coffee berries by the entomopathogenic fungus Beauveria bassiana was also assessed. Brown twig beetle infestation was significantly higher under full sun than under Inga edulis, yet no other shade effects were detected. We demonstrate for the first time how intensified input use might promote pest populations and thus ultimately lead to robusta coffee yield losses.

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<b>Population density of <i>Beauveria bassiana</i> in soil under the action of fungicides and native microbial populations

Cited by 6 publications

References 26 publications

In vitro compatibility of Beauveria bassiana strain ATCC 74040 with copper fungicides

In vitro compatibility of Beauveria bassiana strain ATCC 74040 with copper fungicides

The nesting preference of an invasive ant is associated with the cues produced by actinobacteria in soil

Organic Farming Practices and Shade Trees Reduce Pest Infestations in Robusta Coffee Systems in Amazonia

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