Browsing by Autor "Yordanys Ramos"

Now showing 1 - 6 of 6

Biological control potential of two Beauveria bassiana isolates against the stink bugs Nezara viridula L. and Piezodorus guildinii Westwood (Hemiptera: Pentatomidae) in common bean
(Springer Nature, 2024) Yordanys Ramos; Orelvis Portal; Nicolai V. Meyling; Ingeborg Klingen
Abstract Background The stink bugs, Nezara viridula L. and Piezodorus guildinii Westwood (Hemiptera: Pentatomidae) are the most important and widespread species of polyphagous stink bugs in the tropical and subtropical regions of Latin America, which affect the quality and yield of the common bean ( Phaseolus vulgaris L.). The use of synthetic chemical insecticides is the major control strategy to manage stink bugs in common beans and alternatives are needed. In this study, mortality and median Lethal Time (LT 50 ) of two Cuban isolates of the entomopathogenic fungus Beauveria bassiana (18 S-O-R and 96 P-O-E), as well as one commercial Cuban isolate (Bb-18), at a concentration of 1 × 10 8 conidia/ml were evaluated. These evaluations were conducted against both stink bug species using Petri dish bioassays and a semi-field experiment in common beans. Results In Petri dish bioassays, the isolates 18 S-O-R and 96 P-O-E caused 100% mortality of both N. viridula and P. guildinii . This was significantly higher than for isolate Bb-18, which caused 86.3% N. viridula and 81.3% P. guildinii mortality. In the semi-field experiment, when pooling both stink bug species, total mortality after 14 days was 91.3% for 18 S-O-R, 80.0% for 96 P-O-E and 73.8% for Bb-18 isolates. LT 50 value for isolate 18 S-O-R tested under laboratory conditions was 6.04 ± 0.18 days for N. viridula and 5.32 ± 0.14 days for P. guildinii at the same concentration of 1 × 10 8 conidia/ml . LT 50 value for isolate 18 S-O-R in semi field was 6.79 ± 0.37 days for N. viridula and 7.71 ± 0.32 days for P. guildinii at 1 × 10 8 conidia/ml. Conclusion The study highlights the potential of B. bassiana 18 S-O-R as a promising candidate for control of stink bugs in common bean under tropical conditions as an alternative to conventional chemical insecticides in integrated pest management (IPM) programs. Moving forward, further research should focus on validating the efficacy under diverse field conditions and integrating application methods into practical IPM approaches. Future use of B. bassiana will enhance sustainability and reduce environmental impacts associated with pesticide use.
Diversity and abundance of stink bugs egg parasitoids from organic and conventional fields in Cuba
(Springer Nature, 2024) Yordanys Ramos; Daniel Ricardo Sosa‐Gómez; Orelvis Portal
EFFECT OF SYNTHETIC PESTICIDES ON CONIDIAL GERMINATION AND ENDOPHYTIC ACTIVITY OF Beauveria bassiana AND Metarhizium anisopliae IN COMMON BEAN PLANTS
(University of Concepción, 2022) Yordanys Ramos; Alberto D. Taibo; Celeste Paola D’Alessandro
Common bean (Phaseolus vulgaris L.) is an important legume crop worldwide. Endophytic fungi have proven effective as biocontrol agents in several crops, but they can be affected by pesticides. The aim of this study was to evaluate the effect of synthetic pesticides on the conidial germination and endophytic activity of Beauveria bassiana and Metarhizium anisopliae in P. vulgaris. Three fungicides (Mancozeb, Tebuconazole and Zinc Ethylene-bis), three insecticides (Abamectin, Diazinon and Spirotetramat) and one herbicide (Glufosinate) were evaluated. Each pesticide was applied at the application rate recommended by the manufacturer and also using one-half of the application rate on the commercial strains B. bassiana Bb-18 and M. anisopliae Ma-30. Tebuconazole, Mancozeb and Glufosinate totally inhibited conidial germination. Spirotetramat and Diazinon resulted in a less pronounced negative effect on B. bassiana and M. anisopliae germination. However, Spirotetramat has the lowest impact on the entomopathogenic fungi, allowing for 86 and 74% germination of B. bassiana and M. anisopliae, respectively. Tebuconazole and Mancozeb affected the endophytic activity of the entomopathogenic fungi studied. At one-half of the recommended concentration, Spirotetramat and Zinc Ethylene-bis allowed for the total colonization of B. bassiana in roots of common bean, whereas M. anisopliae reached a colonization of 75%. These results indicate that Spirotetramat, Zinc Ethylene-bis and Diazinon can be used in combination with B. bassiana Ba-18 and M. anisopliae Ma-30. However, Tebuconazole, Mancozeb and Glufosinate should not be combined with these entomopathogenic fungi in Integrated Pest Management programs.
Endophytic establishment of Beauveria bassiana and Metarhizium anisopliae in maize plants and its effect against Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) larvae
(Springer Nature, 2020) Yordanys Ramos; Alberto Daniel Taibo; Jorge Ariel Jiménez; Orelvis Portal
Abstract The aim of the present study was to evaluate the artificial establishment of Beauveria bassiana and Metarhizium anisopliae as endophytes in maize plants, and its effect in controlling the fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) larvae. The commercial strains B. bassiana Bb-18 and M. anisopliae Ma-30 were concentrated at 1 × 10 8 conidia ml −1 , and the soil drench method was used to establish them as endophytes in maize plant parts. The biological control assays were conducted under laboratory conditions on second and fourth larval instars of S. frugiperda . B. bassiana colonized roots, stems, and leaves of maize tissues. However, a high occurrence of B. bassiana was obtained in roots than leaves and stems with 25, 10, and 5 isolations, respectively, whereas M. anisopliae was only acquired on roots. Both entomopathogenic fungi caused (100%) mortality on the second instar larvae. In addition, B. bassiana and M. anisopliae killed (87 and 75%) of the fourth larval instars, respectively. The fungus M. anisopliae caused the highest sporulation rates during the study. These results suggest that the entomopathogenic fungi might contribute to a sustainable S. frugiperda management in maize production in Cuba.
First report of Nezara viridula transmitting Eremothecium sp. to common bean grains in Cuba
(Springer Science+Business Media, 2025) Yordanys Ramos; Orelvis Portal
Host weed plant preference of Piezodorus guildinii Westwood (Hemiptera: Pentatomidae) and its susceptibility to Beauveria bassiana in common beans management
(Springer Nature, 2024) Yordanys Ramos; Daniel Ricardo Sosa‐Gómez; Orelvis Portal