Bioinsecticides with lower concentrations of endospores/crystals and without loss of efficiency are economically advantageous for pest biocontrol. In addition to Cry proteins, other Bacillus thuringiensis (Bt) toxins in culture supernatants (SN) have biocontrol potential (e.g., Vip3A, Cry1I, Sip1), whereas others are unwanted (β-exotoxins), as they display widespread toxicity across taxa. A strain simultaneously providing distinct toxin activities in crystals and SN would be desirable for bioinsecticides development; however, strains secreting β-exotoxins should be discarded, independently of other useful entomotoxins. Entomotoxicity of crystals and SN from a Brazilian Bt tolworthi strain (Btt01) was tested against Spodoptera frugiperda to assess the potential for biocontrol-product development based on more than one type of toxin/activity. Tests showed that 107 endospores mL−1 caused >80% of larvae mortality, suggesting Btt01 may be used in similar concentrations as those of other Bt-based biopesticides. When it was applied to cornfields, a significant 60% reduction of larvae infestation was observed. However, bioassays with Btt01 SN revealed a thermostable toxic activity. Physicochemical characterization strongly suggests the presence of unwanted β-exotoxins, with isolate-specific temporal variation in its secretion. Knowledge of the temporal pattern of secretion/activity in culture for all forms of toxins produced by a single strain is required to both detect useful activities and avoid the potential lack of identification of undesirable toxins. These findings are discussed in the contexts of commercial Bt product development, advantages of multiple-activity strains, and care and handling recommended for large-scale fermentation systems.

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Growth promoting rhizobacteria may increase the yield of some crops. Several microbial products that stimulate plant growth have been marketed. Therefore, the objective of this study was to evaluate the effect of bacteria from Bacillus genera on the production of commercial carrot roots (Daucus carota L.) in field conditions. The following isolates: SF 264 (Bacillus spp.), SF 268 (Bacillus spp.) and commercial formulations based on SF 202 (Rizos®, B. subtilis), SF 266 (Quartz®, B. methylotrophicus) and SF 267 (Onix®, B. methylotrophicus) were evaluated in four experiments conducted in commercial fields of carrot production in the municipality of Rio Paranaíba, Minas Gerais-Brazil. Each plot was 6 m long and 1.75 m wide (10.5 m 2) including four double rows. An additional treatment containing only water was the control treatment. The experiment was designed as randomized blocks with five replications. The products Rizos ® , Quartz ® and Onix ® containing Bacillus spp. increased the production of commercial carrots roots of all cultivars and sites. The SF 268 and SF 264 isolates were efficient only in two and three experiments, respectively.

Bacteria belonging to the genus Bacillus can promote plant growth and suppress plant-parasitic nematode populations. Based on this hypothesis, eight strains of the bacterium (SF 262, SF 264, SF 266, SF 267, SF 268, SF 271, SF 292 and SF 629) were formulated and applied as a seed treatment and/or sprayed on the soil surface with the aim of controlling Pratylenchys brachyurus in common bean under field conditions. The application of the bacterial isolates neither improved the grain yield and the root mass nor reduced the number of nematodes in the soil and in the roots of common bean. Thus none of the isolates of Bacillus spp. evaluated in this work are promising for the control of the lesion nematode on common bean.