Effect of pH and water activity over Nomuraea rileyi (Hyphomycetes) development
Main Article Content
The armyworm Spodoptera frugiperda causes important economical losses in corn, cotton and sorghum crops. an alternative for its control is the use of the entomopathogenic fungus Nomuraea rileyi, which causes natural epizootics in the field. At the Biological Control Laboratory of Corpoica, two mycopesticides were developed based on a native isolate of this fungus, formulated as an emulsifiable concentrate and as a dispersible granule. The insecticidal activity of the products was significantly lower than that obtained with the unformulated fungus, possibly due to the formulation, considering the high susceptibility of this fungus to abiotic factors. For this reason, the main objective of the present work was to evaluate the effect of pH and water activity (Wa) on the germination, sporulation, radial growth and insecticidal activity of N. rileyi. These parameters were evaluated by using Ym culture media adjusted to pH values from 4 to 9 and Wa values from 0.950 to 0.998. Results showed that both development and insecticidal activity of the microorganism were affected by pH, the best results being obtained with a pH range from 5 to 7. The microorganism needed high values of Wa (> 0.99) for germinating, growing and developing an infection in the insect. Results will allow the optimization of formulations, adjusting to the most adequate conditions for development and efficacy of the microorganism.
ABBOTT, W. 1925. A method of computing the effectiveness of an insecticide. Journal of Economic Entomology 18:265-267.
BOSA, C.; CHAVEZ, D.; TORR ES, L.; PAR ÍS, A.; VILLAMIZAR, L.; COTES, A. 2004. Evaluación de aislamientos nativos de Nomuraea rileyi para el control de Spodoptera frugiperda (Lepidoptera: Noctuidae). Revista Colombiana de Entomología 30 (1): 93-97.
CLARCKSON, J.; CHARNLEY, K. 1996. New insights into the mechanisms of fungal pathogenesis in insects. Trends in Microbiology 4 (5): 197-203.
GARCÍA, I.; DEL POZO, E. 1999. Aislamiento y producción de conidios de Nomuraea rileyi (Farlow) Samson y su virulencia en larvas de Spodoptera frugiperda (J. E. Smith). Revista Protección Vegetal 14 (2): 95 -100.
GARCÍA, F.; MOSQUERA, M.; VARGAS, C.; ROJAS, L. 2002. Control biológico, microbiológico y físico de Spodoptera frugiperda (Lepidoptera: Noctuidae) plaga del maíz y otros cultivos en Colombia. Revista Colombiana de Entomología 28 (1): 53-60.
GARCIA, M.; VILLAMIZAR, L.; COTES, A. 2007a. Compatibility of Trichoderma koningii with chemical fungicides. IOBC/ wprs Bulletin 30 (6): 441-445.
GARCIA, M.; VILLAMIZAR, L; TORR ES, L.; COTES, A. 2007b. Efecto de subcultivos sucesivos de Beauveria bassiana sobre sus características y actividad contra Premnotrypes vorax. Revista Manejo Integrado de Plagas y Agroecología 77: 50-56
HALLSWORT H, J.; MAGAN, N. 1995. Manipulation of intracellular glycerol and erythritol enhances germination of conidia at low water availability. Microbiology 141: 1109-1115.
HALLSWORT H, J.; MAGAN, N. 1997. Culture age, temperature and pH affect the polyol and trehalose contents of fungal propagules. Applied and Environmental Microbiology 62 (7): 2435-2442.
HALLSWORT H, J.; MAGAN, N. 1999. Water and temperature relations of growth of the entomogenous fungi Beauveria bassiana, Metarhizium anisopliae, and Paecilomyces farinosus. Journal of Invertebrate Pathology 74 (3): 261-266.
HUMPHREYS, A.; MAT EWELE, P.; TRINCI, A. 1989. Effects of water activity on morphology, growth and blastospore producpH y agua en Nomuraea rileyi 144 tion of Beauveria bassiana, Metarhizium anisopliae and Paecilomyces farinosus in batch and fed batch culture. Mycological research 92 (3): 257-264.
LAZZARINNI, G.; NUNES, F.; LUZ, C. 2006. Impact of moisture on in vitro germination of Metarhizium anisopliae and Beauveria bassiana and their activity on Triatoma infestans. Mycological Research 110: 485-492.
MADIGAN, M.; MARTINKO, J.; PARKER, J. 1999. Brock Biología de los microorganismos. Octava Edición. Prentice Hall. 984p
MINGOT, J.; ESPESO, E.; ELÍECER, D.; PEÑALVA, M. 2001. Ambient pH signaling regulates nuclear localization of the Aspergillus nidulans PacC Transcription Factor. Molecular and Cellular Biology 21 (5): 1688-1699.
MOORE, E. 1996. Fundamentals of the fungi. Cuarta Edición. Prentice Hall. New Jersey. 574 p.
RONCAL, T.; CORDOBE, S.; STERNER, O.; UGALDE, U. 2002. Conidiation in Penicillium cycloium induced by conidiogenone, an endogenous diterpene. Eukaryotic cell 1: 823-829.
RONCAL, T.; UGALDE, U. 2003. Conidiation induction in Penicillium. Research in Microbiology 154: 539-546.
SAUTOUR , M.; ROUGET, A.; DANTIGNY, P.; DIVIES, C.; BENSOUSSAN, M. 2001. Prediction of conidial germination of Penicillium chrysogenum as influenced by temperature, water activity and pH. Letters in Applied Microbiology 32: 131-134.
SCHMIT, J.; BRODY, S. 1975. Neurospora crassa conidial germination: role of endogenous aminoacids pools. Journal of Bacteriology 124: 232-242.
St. LEGER, R.; JOSHI, L.; ROBERTS , D. 1998. Ambient pH is a major determinat in the expression of cuticle degrading enzymes and hydrophobin by Metarhizium anisopliae. Applied and Environmental Microbiology 64 (2): 709-713.
TRUMPER, E.; EDELSTEIN, J.; LECUONA, R. 2004. Selection of culture media and in vitro assessment of temperature-dependent development of Nomuraea rileyi. Neotropical Entomology 33 (6): 737-742.
VILLAMIZAR, L.; ARRIERO, C.; BOSA, C.; COTES, A. 2004.Desarrollo de preformulados a base de Nomuraea rileyi para el control de Spodoptera frugiperda (Lepidoptera: Noctuidae). Revista Colombiana de Entomología 30 (1): 99-105.
YPSILOS, K.; MAGAN, N. 2004. Impact of waterstress and washing treatments on production, synthesis and retention of endogenous sugar alcohols and germinability of Metarhizium anisopliae blastospores. Mycological Research 108 (11): 1337-1345.
- CARLOS FELIPE BOSA-O., ALBA MARINA COTES-P., Effect of culture conditions on the entomopathogenic activity of Serratia marcescens against Tocia solanivora (Lepidoptera: Gelechiidae) , Revista Colombiana de Entomología: Vol. 30 No. 1 (2004)
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Authors retain the copyright on their work and are responsible for the ideas expressed in them. Once a manuscript is approved for publication, authors are asked for a publication license for the term of legal protection, for all territories that allows the use, dissemination and disclosure of the same.