Bacillus thuringiensis monogenic strains: screening and interactions with insecticides used against rice pests

Pinto, Laura Massochin Nunes; Dörr, Natália C; Ribeiro, Ana Paula A; Salles, Silvia Martins de; Oliveira, Jaime Vargas de; Menezes, Valmir Gaedke; Fiúza, Lidia Mariana

doi:10.1590/s1517-83822012000200025

Cited by 11 publications

(8 citation statements)

References 33 publications

(32 reference statements)

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“…Soil samples from jhum, aquatic and fallow habitats were used as a source material for isolation of native Bt strains which led to the discovery of isolates with higher toxicity Ramalakshmi and Udayasuriyan, 2010;Martin and Travers, 1989;Liang et al, 2011;Pinto et al, 2012;Xue et al, 2008 . Results showed that about 52.38% of the 42 samples were positive for Bt and yielded 82 isolates in jhum-forest and jhum-agriculture soils.…”

Section: Biochemical Characterization and Morphology Of Crystalline Imentioning

confidence: 99%

Diversity and Toxicity of <i>Bacillus thuringiensis</i> from Shifting Cultivation (Jhum) Habitat

2016

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Bacillus thuringiensis (Bt) strains were isolated from jhum-agriculture, jhum-forest, aquatic and fallow soil samples from Mizoram by acetate selection method. Isolates were characterized for biochemical typing, cry gene and protein profiling, growth curve study and toxicity against Culex tritaeniorhynchus. Bt frequency was high in jhum-agriculture land (69.56%) whereas low in jhum-forest soils (31.57%). Bt was found to be abundant in jhum shifting cultivation soil with an index ranging between 0.010 and 0.015. Majority of the isolates from jhum soils produced oval and spherical crystals and showed eleven types of crystal proteins groups. PCR analysis revealed predominance of dipteran-active cry genes (cry4 and cry9). The variations in crystal morphology, cry genes and Cry protein (s) from the isolates of Bt revealed molecular diversity. Higher mortality, lower lethal dose, and lesser time to kill were observed in Bt isolates from jhum soils than aquatic and fallow habitats. Based on the toxicity test, SC1 and HP7 isolates containing cry 4 and cry 9 genes showed higher activity. Growth curve analysis showed significant variations among Bt isolates to reach the sporulating stage. Higher growth index and lower mean generation time were observed in SC1 and HP7 Bt isolates. Bt strains express different endotoxin genes and crystal proteins and their harvesting time also varied from strain to strain. Significant variation was found in Bt isolates from jhum habitats in relation to the cry gene composition, protein profiling and toxicity. Results from this study suggest that novel Bt entomopathogens may complement for regulating mosquito vectors.

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Section: Biochemical Characterization and Morphology Of Crystalline Imentioning

confidence: 99%

Diversity and Toxicity of <i>Bacillus thuringiensis</i> from Shifting Cultivation (Jhum) Habitat

2016

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“…This variable can be used to promote compatibility (Batistafilho et al, 2001;Manachini, 2002;Fadare and Amusa, 2003;Pinto et al, 2012). However, we observed in some cases that the highest concentration of a chemical product allowed better development of the bacterium (Figures 1 and 2).…”

mentioning

confidence: 63%

“…The sensitivity of B. thuringiensis to bifenthrin and bifenthrin + carbosulfan, besides being related to the chemical molecule of each active ingredient, can also be negatively influenced by the presence of additional compounds in the commercial products, such as emulsifiers and other additives (Dougherty et al, 1970;Morris and Armstrong, 1975;Morris, 1977). Among the active ingredients of the endosulfan insecticide class, profenofos + lufenuron and malathion also lowered the development of B. thuringiensis in vitro Batista-filho et al, 2003;Pinto et al, 2012), indicating a high sensitivity of this microrganism to a range of toxic synthetic chemical compounds. Alves et al (1998) emphasizes that the high toxicity of a tested commercial pesticide under laboratory conditions does not always have the same behavior in field, but infer an occurrence of future problems due to incompatibility.…”

mentioning

confidence: 99%

Compatibility among insecticides, acaricides, and Bacillus thuringiensis used to control Tetranychus urticae (Acari: Tetranychidae) and Heliothis virescens (Lepidoptera: Noctuidae) in cotton fields

Agostini¹,

Duarte²,

Volpe³

et al. 2014

Afr. J. Agric. Res.

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Tetranychus urticae and Heliothis virescens are major pests of cotton and have been managed by the indiscriminate use of acaricides and insecticides. The combined use of chemical and biological products, in particular Bacillus thuringiensis-based products, and the rotation of active ingredients can reduce the negative effects of pesticides and can contribute to the management of resistance, control costs, and help the environment. Therefore, research on the compatibility of control tactics is essential to successful integrated pest management (IPM). The objective of this research was to determine the compatibility of chemical pesticides and a B. thuringiensis-based product in the control of T. urticae and H. virescens in cotton fields. Spiromesifen was compatible with B. thuringiensis var. kurstaki. However, it reduced the development of B. thuringiensis by 40 to 65% relative to the control. Bifenthrin was toxic or moderately toxic to B. thuringiensis depending on the concentration used. Compared to the control, the vegetative growth of B. thuringiensis was 20% lower when used with bifenthrin. Bifenthrin + carbosulfan was highly toxic to B. thuringiensis, decreasing its vegetative growth to less than 1% compared to the control. Spiromesifen was compatible with the recommended concentrations of B. thuringiensis var. kurstaki.

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“…The inhibition or reduction of Bt vegetative growth is common when the doses of pesticides, such as thiamethoxan, malathion, and fipronil, in combination with Bt biopesticides are increased. However, at the doses recommended by the manufacturers, there are no incompatibility issues between Bt biopesticides and chemical insecticides 29 , 30 . Therefore, altering the recommended doses of chemicals used for preparing Bt biopesticide spray mixtures increases the probability of incompatibility.…”

Section: Discussionmentioning

confidence: 99%

Compatibility of Bt biopesticides and adjuvants for Spodoptera frugiperda control

Santos

Nascimento

Gonçalves

et al. 2021

Sci Rep

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Spodoptera frugiperda is a pest of economic importance for several crops with resistance reports to Bt crops and pesticides. Eco-friendly Bt biopesticides may be an alternative to chemical insecticides due to their selectivity and specificity. However, the efficacy of Bt biopesticides may be influenced by the association with other chemicals, such as adjuvants. This study evaluated the compatibility and toxicity of Bt biopesticides mixed with adjuvants for the control of S. frugiperda. The treatments included the association of Dipel SC and Dipel PM with adjuvants. Compatibility tests were used to evaluate the Bt mixture. Bt suspensions obtained from mixtures of Bt and adjuvants at 106 and 3 × 108 spores/mL−1 were used to evaluate S. frugiperda mortality and distilled water was used as the control. The addition of the adjuvant LI increased growth and sporulation, indicating compatibility with Bt biopesticides. The other adjuvants were toxic to reducing Bt growth and sporulation. Only the mixture of Bt with LI and Bt alone was effective to S. frugiperda. The addition of adjuvants to Bt biopesticide affect the Bt sporulation, growth and mortality.

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Bacillus thuringiensis monogenic strains: screening and interactions with insecticides used against rice pests

Cited by 11 publications

References 33 publications

Diversity and Toxicity of <i>Bacillus thuringiensis</i> from Shifting Cultivation (Jhum) Habitat

Diversity and Toxicity of <i>Bacillus thuringiensis</i> from Shifting Cultivation (Jhum) Habitat

Compatibility among insecticides, acaricides, and Bacillus thuringiensis used to control Tetranychus urticae (Acari: Tetranychidae) and Heliothis virescens (Lepidoptera: Noctuidae) in cotton fields

Compatibility of Bt biopesticides and adjuvants for Spodoptera frugiperda control

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