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

Soares, Flávia Barbosa; Monteiro, Antonio Carlos; Barbosa, José Carlos; Mochi, Dinalva Alves

doi:10.4025/actasciagron.v39i4.32816

Flávia Barbosa Soares

Departamento de Produção Vegetal, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Via de Acesso Prof. Paulo Donato Castellane, s./n., 14884-900, Jaboticabal, São Paulo, Brazil.

Antonio Carlos Monteiro

Departamento de Produção Vegetal, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Via de Acesso Prof. Paulo Donato Castellane, s./n., 14884-900, Jaboticabal, São Paulo, Brazil.

José Carlos Barbosa

Departamento de Ciências Exatas, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual de São Paulo, Jaboticabal, São Paulo, Brasil.

Dinalva Alves Mochi ^**Author for correpondence. E-mail: dmochi@hotmail.com

Departamento de Produção Vegetal, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Via de Acesso Prof. Paulo Donato Castellane, s./n., 14884-900, Jaboticabal, São Paulo, Brazil.

*Author for correpondence. E-mail: dmochi@hotmail.com

Figures (4)
Tables (3)

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Figure 1
Interactions between Beauveria bassiana population and other naturally-occurring microbial populations in soil treated with fungicide containing the active ingredient thiophanate-methyl, applied A) 1 hour before inoculation with fungus, B) 1 hour after inoculation with fungus, C) 48 hours after inoculation with fungus. D is the control, to which no fungicide was added. Means (± standard deviation) with the same lower case letters for the incubation period of the same population were not significantly different (Tukey’s test, 5% probability). Statistical analysis performed and graphs plotted with data transformed in log (x+5).

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Figure 2
Interactions between Beauveria bassiana population and other naturally-occurring microbial populations in soil treated with fungicide containing the active ingredient pyraclostrobin, applied A) 1 hour before inoculation with fungus, B) 1 hour after inoculation with fungus, C) 48 hours after inoculation with fungus. D is the control, to which no fungicide was added. Means (± standard deviation) with the same lower case letters for the incubation period of the same population were not significantly different (Tukey’s test, 5% probability). Statistical analysis was performed and graphs plotted with data transformed in log (x+5).

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Figure 3
Interactions between Beauveria bassiana population and other naturally-occurring microbial populations in soil treated with fungicide containing the active ingredient mancozeb, applied A) 1 hour before inoculation with fungus, B) 1 hour after inoculation with fungus, C) 48 hours after inoculation with fungus. D is the control, to which no fungicide was added. Means (± standard deviation) with the same lower case letters for the incubation period of the same population were not significantly different (Tukey’s test, 5% probability). Statistical analysis performed and graphs plotted with data transformed in log (x+5).

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Figure 4
Interactions between Beauveria bassiana population and other naturally-occurring microbial populations in soil treated with fungicide containing the active ingredient copper oxychloride, applied A) 1 hour before inoculation with fungus, B) 1 hour after inoculation with fungus, C) 48 hours after inoculation with fungus. D is the control, to which no fungicide was added. Means (± standard deviation) with the same lower case letters for the incubation period of the same population were not significantly different (Tukey’s test, 5% probability). Statistical analysis performed and graphs plotted with data transformed in log (x+5).

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Table 1
Fungicides^a used in this study with the entomopathogenic fungus Beauveria bassiana isolate JAB 06.

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Table 2
Percent germination of Beauveria bassiana conidia cultivated on media containing fungicides at the recommended doses, Biological Index (BI) and fungal toxicity rating of the fungicides.

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Table 3
Correlations between Beauveria bassian a population and populations of bacteria, fungi and actinomycetes obtained for treatments with different fungicides.

Active ingredient	Chemical group	Recommended dose	Spray volume
Thiophanate-methyl	Benzimidazoles	250 g of c.p. 100 liters^-1 of water	1000 liters ha^-1
Pyraclostrobin	Strobilurins	15 ml of c.p. 100 liters^-1 of water	2000 liters ha^-1
Mancozeb	Dithiocarbamates	200 g of c.p. 100 liters^-1 of water	400 liters ha^-1
Copper oxychloride	Cuprics	250 g of c.p. 100 liters^-1 of water	1000 liters ha^-1

Fungicide	Germination	BI	Toxicological classification
Control	97.07±1.48 a
Copper oxychloride	93.95±0.66 a	9	Toxic
Thiophanate-methyl	93.69±0.82 a	9	Toxic
Pyraclostrobin	74.26±27.41 ab	7	Toxic
Mancozeb	50.10± 6.18 b	3	Toxic
F-test	8.37**
C.V. (%)	12.77

Treatment	Pearson coefficients of correlation (r)^a
Treatment	Bacteria	Fungi	Actinomycetes
Thiophanate-methyl	-0.17005^NS	0.91740**	-0.49914*
Addition 1 hour BIBb	-0.29284^NS	0.78532**	-0.57798**
Addition 1 hour AIBb	-0.32250^NS	0.88365**	-0.51566*
Addition 48 hours AIBb	-0.55585*	0.82688**	-0.40840^NS
Control
Pyraclostrobin	0.21512^NS	-0.65064**	0.58913**
Addition 1 hour BIBb	0.27867^NS	-0.17031^NS	0.32915^NS
Addition 1 hour AIBb	0.04262^NS	-0.58207**	0.61853**
Addition 48 hours AIBb	0.22528^NS	-0.75968**	0.35766^NS
Control
Mancozeb	0.05629^NS	0.06766^NS	-0.48714*
Addition 1 hour BIBb	0.08069^NS	0.19538^NS	0.28576^NS
Addition 1 hour AIBb	0.34106^NS	0.19314^NS	0.16840^NS
Addition 48 hours AIBb	0.18944^NS	0.58354**	-0.41728^NS
Control
Copper oxychloride	0.69148**	0.84943**	-0.46717*
Addition 1 hour BIBb	0.01847^NS	0.91818**	-0.37650^NS
Addition 1 hour AIBb	0.82772**	0.72213**	-0.22961^NS
Addition 48 hours AIBb	0.58644**	0.95867**	-0.36780^NS

[1] *Author for correpondence. E-mail: dmochi@hotmail.com

Brasil

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Population density of Beauveria bassiana in soil under the action of fungicides and native microbial populations

Densidade populacional de Beauveria bassiana no solo sob a ação de fungicidas e de populações microbianas nativas

ABSTRACT.