Activity of spore-crystal mixtures of new Bacillus thuringiensis strains against Dendrolimus pini (Lepidoptera: Lasiocampidae) and Spodoptera exigua (Lepidoptera: Noctuidae)

Abstract

We estimated the usefulness of spore-crystals preparations of the two B. thuringiensis isolates, MPU B9 and MPU B54, for reducing the number of pests. The potential insecticidal toxicities of B. thuringiensis isolates were assessed by the analysis of the genes coding for crystalline proteins. The activities of spore-crystals preparations were determined against Dendrolimus pini L. (Lepidoptera: Lasiocampidae) and compared with the toxicity of spores and crystals of B. thuringiensis subsp. kurstaki HD-1 from commercial biopesticide Foray. Although the analysis of crystalline toxin gene profiles indicated potentially higher activities of MPU B9 and MPU B54 crystals against the pests than that of HD-1, the toxicities of isolate and HD-1 preparations against D. pini caterpillars were similar. The LC50 amounted to 3.42×104 spores and crystals for HD-1, 3.36×104 for MPU B9 and 3.5×104 for MPU B54. Additionally, the toxicity of the MPU B54 preparation was evaluated against Spodoptera exigua (Hubner) (Lepidoptera: Noctuidae). The LC50 was 4.5×105 spores and crystals of MPU B54, and 2.69×106 spores and crystals of HD-1. The LC50 of the MPU B54 preparation against S. exigua was approximately six-fold higher than that of HD-1. However, due to the very wide fiducidal limits for LC50 values, which for both preparations overlap to a large extent, the toxicity of the preparations should be considered the same. The varied profiles of crystalline toxin genes and important toxicity of spore-crystal mixtures of isolates against S. exigua and D. pini indicate the effectiveness of the mixtures against pests and make the strains an alternative for HD-1 for reducing the number of insects.

Chromosome-Level Genome Assembly Reveals Significant Gene Expansion in the Toll and IMD Signaling Pathways of Dendrolimus kikuchii

“…Pest management of D. kikuchii mostly involves routine technologies, for instance, manual, physical, chemical, and biocontrol methods as well as forestry management. Biocontrol of the genus Dendrolimus with organisms such as Trichogramma dendrolimi, Beauveria bassiana, and Bacillus thuringiensis is safe, environmentally friendly, and effective long-term (Hou, 1987;Hou, 1993;Kunimi, 2007;Konecka et al, 2019). However, despite the broad prospect of utilizing pathogens in the biocontrol of D. kikuchii, the molecular mechanisms of interaction between D. kikuchii and such pathogens are not well understood.…”

Possible interference of Bacillus thuringiensis in the survival and behavior of Africanized honey bees (Apis mellifera)

“…4 Programa de Pós-Graduação em Zootecnia (PPGZO), UTFPR-DV, Dois Vizinhos, Paraná CEP 85.660-000, Brazil. * email: profmichele@gmail.com biological control agents, the bacterium Bacillus thuringiensis (Bt), is considered successful 18 and efficient and is recommended for the control of insects, including those of Lepidoptera, Coleoptera, and Hymenoptera [19][20][21][22][23] . In general, the side effects of a biological agent vary for different organisms, owing to the greater specificity for the target organism.…”

Synergistic interaction between carvacrol and Bacillus thuringiensis crystalline proteins against Cydia pomonella and Spodoptera exigua

“…B. thuringiensis MPU B9 was isolated from the intestinal tract of dead caterpillar of codling moth Cydia pomonella during epizootics caused by naturally occurred bacterial infection in the laboratory-cultured line of the insect (Konecka et al 2007a). B. thuringiensis MPU B54 was cultured from soil sample (Konecka et al 2018c).…”

“…Moreover, mass spectrometry analysis revealed that MPU B9 crystals contained Cry1Aa, 1Ba, 1Ca, 1D, and 9E toxins (Baranek et al 2017). Bacterial crystals alone or with spores showed high insecticidal activity against insect pests (Konecka et al 2018c(Konecka et al , 2015(Konecka et al , 2012(Konecka et al , 2007b. B. thuringiensis strain MPU B54 harbored the following genes: cry1Aa, cry1Ab, cry1C, cry1D, cry1I, cry2Ab, cry9B, and cry9E.…”

“…B. thuringiensis strain MPU B54 harbored the following genes: cry1Aa, cry1Ab, cry1C, cry1D, cry1I, cry2Ab, cry9B, and cry9E. Crystals of the strain MPU B54 exhibited significant insecticidal activity against moths (Konecka et al 2018c).…”