The entomopathogenic fungus Beauveria pseudobassiana strain RGM 2184 can reach a maximum efficacy of 80% against the quarantine pest Lobesia botrana in field assays. In this study, the RGM 2184 genome was sequenced, and genome mining analyses were performed to predict the factors involved in its insecticidal activity. Additionally, the metabolic profiling of the RMG 2184 culture’s supernatants was analyzed by mass spectrometry, and the insecticidal activity from one of these extracts was evaluated in Galleria mellonella larvae. The genome analysis resulted in 114 genes encoding for extracellular enzymes, four biosynthetic gene clusters reported as producers of insecticidal and bactericidal factors (oosporein, beauvericin, desmethylbassianin, and beauveriolide), 20 toxins, and at least 40 undescribed potential biocontrol factors (polyketides and nonribosomal peptides). Comparative genomic analysis revealed that 65–95% of these genes are Beauveria genus-specific. Metabolic profiling of supernatant extracts from RGM 2184 cultures exhibited secondary metabolites such as beauveriolide, oosporein, inflatin C, and bassiatin. However, a number of detected metabolites still remain undescribed. The metabolite extract caused 79% mortality of Galleria mellonella larvae at 28 days. The results of this research lay the groundwork for the study of new insecticidal molecules.
Lobesia botrana (Denis and Shiffermüller) (Lepidoptera: Tortricidae) is one of the main pests that affect the production and export of table grapes in Chile. Because this pest has quarantine status, the fruit must be fumigated with methyl bromide, which reduces the fruit’s export competitiveness in the destination market. In the present study, to help resolve this issue, six native entomopathogenic fungi were identified through multilocus analysis, including three Beauveria pseudobassiana and three Metarhizium robertsii. These fungi were evaluated in the laboratory to control L. botrana in its pupal stage in a silk cocoon and compared against a biological control product. Formulations with additional carbon sources improved the performance of the fungi. The treatments with outstanding performance contained the fungal strains B. pseudobassiana RGM 2184 and M. robertsii RGM 678. These strains were evaluated in the field during the winter season in two different regions of the country; the strains reached maximum efficacies of 80% and 88%, respectively, at 21 days post first application. Therefore, entomopathogenic fungi can contribute to reducing pupal populations in winter, thereby decreasing the moth population in spring–summer.
Objective Lobesia botrana, the European grapevine moth, affects Vitis vinifera L. and other species of economic importance in a number of countries through damage caused by its larvae in berries and associated secondary diseases such as Botrytis cinerea . Control of the moth in urban areas is difficult due to poor chemical management of infested plants in houses. Additionally, in winter, L. botrana is in its pupal stage covered with a cocoon that prevents the penetration of chemical pesticides. For this reason, the objective of this work was to control the pupal stage with a formulation based on the entomopathogenic fungus Beauveria pseudobassiana in urban areas. Results The strain RGM 1747 was identified as B. pseudobassiana by multilocus sequence analysis . The biocontrol activity of this formulated fungus against the infestation of vines with breeding pupae without cocoons showed 100% infection 21 days after inoculation under winter conditions. Finally, the biocontrol activity of the formulated fungus against natural infestations of L. botrana in winter in urban areas reached an efficacy of 51%. This result suggests that the B. pseudobassiana formulation is able to penetrate the cocoon and contributes to the integrated pest management of L. botrana .
Objective: Lobesia botrana, the European grapevine moth, affects Vitis vinifera L. and other species of economic importance in a number of countries through damage caused by its larvae in berries and associated secondary diseases such as Botrytis cinerea. Control of the moth in urban areas is difficult due to poor chemical management of infested plants in houses. Additionally, in winter, L. botrana is in its pupal stage covered with a cocoon that prevents the penetration of chemical pesticides. For this reason, the objective of this work was to control the pupal stage with a formulation based on the entomopathogenic fungus Beauveria pseudobassiana in urban areas. Results: The present study of the biocontrol activity of the formulated fungus against the infestation of vines with breeding pupae without cocoons showed 100% infection 21 days after inoculation under winter conditions. Finally, the biocontrol activity of the formulated fungus against natural infestations of L. botrana in winter in urban areas reached an efficacy of 51%. This result suggests that the B. pseudobassiana formulation is able to penetrate the cocoon and contributes to the integrated pest management of L. botrana.
N. Vitta, P. Estay, and Chorbadjian, R.A. 2016. Characterization of resistance expression in genotypes of Solanum Section Lycopersicon against Tuta absoluta (Lepidoptera: Gelechiidae). Cien. Inv. Agr. 43(3):366-373. Two studies were conducted with the aim of characterizing the antixenosis and antibiosis resistance expression of genotypes in the Solanum section Lycopersicon against Tuta absoluta (Meyrick). The species used were S. lycopersicum (Fiorentino, Naomi and Belle), S. habrochaites (RCAT030597, PI126446), S. chilense (INIABB79), S. peruvianum (RCAT031296, RCAT039874 and RCAT030403) and S. pimpinellifolium (PI390739). For the antixenosis bioassay, a leaf was removed from plants of each genotype and placed in a cup with a floral foam soaked in water. The cups were stored in cages covered with anti-aphid mesh. The number of eggs per plant was determined seven days after releasing the adults. For the antibiosis bioassay, one leaf per genotype and replication was placed in a plastic cup with floral foam soaked in water, and first-stage tomato leaf miner larvae were placed individually on the leaves. Larval survival, total average male and female pupal weight and consumed foliar area were assessed for each genotype. It was determined that most wild species showed resistance to Tuta absoluta by antixenosis and antibiosis mechanisms. The genotype S. habrochaites (RCAT030597) presented more resistance by antibiosis based on larval survival. Nonetheless, the resistance-level characterization depended on the insect response that was considered because S. chilense was less preferred for oviposition; however, in this genotype, the larval survival in the no-choice assays was among the highest observed. Thus, this study provides comprehensive information on the resistance level of several Solanum genotypes that could be used in further efforts to understand the complex mechanisms underlying Solanum resistance to the tomato leaf miner.
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