Articles
KRESOXIM-METHYL: A CONTRIBUTION TO THE POWDERY MILDEW (SPHAEROTECA PANNOSA (WALL. EX FR.)) CONTROL IN ROSES
Article number
482_33
Pages
223 – 226
Language
Abstract
Rose powdery mildew (Sphaeroteca pannosa (Wallr. ex Fr.)) is the most limiting disease worldwide and the Bogota plateau (Colombia) is not the exception.
Its chemical control is based only in Sterol Biosynthesis Inhibitors (SBI). Therefore, the inclusion of a new fungicide molecule with a completely new mode of action is extremely valuable.
Strobilurins are a good example (Hijwegen et al., 1996). Strobilurins were synthesized in laboratory using Strobilurin A, produced by the fungus Strobilurus tenacellus used as model.
The further improvement of the molecule subsequently led to the discovery of Kresoxim-methyl (Beautement et al., 1991). Kresoxim-methyl works through the interruption of the electron transport in the mitochondrial respiratory chain, at the position of the cytochrome-bc1 complex.
This way, the mitochondria stop providing vital energy in the form of ATP, which is necessary for the metabolic processes occurring in the fungus (Clough, 1993). The present work was realized in Flores La Fragancia S.A., La Herradura farm, located in Subachoque (Cundinamarca) in order to establish the protective and curative-eradicative effects of Kresoxim-methyl on Rose Powdery Mildew (Sphaeroteca pannosa (Wallr. ex Fr.)). Results showed an incidence reduction in the floral buds zone (shoots and renewals) after the second application, from an initial level of 84 % to 19 %. Kresoxim-methyl was proved to be very effective in preventing spore germination, the formation of germ tubes and appresoria, and penetration of the fungus into the leaves.
Additionally, an infection fungus reduction in the vegetative zone (young and mature leaves) from an initial level of 23 % to 11 % was observed, which confirmed its curative and eradicative effect represented in collapsing spore chains and the surface mycelia.
Finally, the number of applications was reduced by 54 % when Kresoxim-methyl was applied in a control program compared with other commercial program, for two months.
It represented a reduction from 11 to 6 applications, with obvious benefits.
Its chemical control is based only in Sterol Biosynthesis Inhibitors (SBI). Therefore, the inclusion of a new fungicide molecule with a completely new mode of action is extremely valuable.
Strobilurins are a good example (Hijwegen et al., 1996). Strobilurins were synthesized in laboratory using Strobilurin A, produced by the fungus Strobilurus tenacellus used as model.
The further improvement of the molecule subsequently led to the discovery of Kresoxim-methyl (Beautement et al., 1991). Kresoxim-methyl works through the interruption of the electron transport in the mitochondrial respiratory chain, at the position of the cytochrome-bc1 complex.
This way, the mitochondria stop providing vital energy in the form of ATP, which is necessary for the metabolic processes occurring in the fungus (Clough, 1993). The present work was realized in Flores La Fragancia S.A., La Herradura farm, located in Subachoque (Cundinamarca) in order to establish the protective and curative-eradicative effects of Kresoxim-methyl on Rose Powdery Mildew (Sphaeroteca pannosa (Wallr. ex Fr.)). Results showed an incidence reduction in the floral buds zone (shoots and renewals) after the second application, from an initial level of 84 % to 19 %. Kresoxim-methyl was proved to be very effective in preventing spore germination, the formation of germ tubes and appresoria, and penetration of the fungus into the leaves.
Additionally, an infection fungus reduction in the vegetative zone (young and mature leaves) from an initial level of 23 % to 11 % was observed, which confirmed its curative and eradicative effect represented in collapsing spore chains and the surface mycelia.
Finally, the number of applications was reduced by 54 % when Kresoxim-methyl was applied in a control program compared with other commercial program, for two months.
It represented a reduction from 11 to 6 applications, with obvious benefits.
Authors
J. García, C. Rodríguez, D.F. Meza
Keywords
Strobilurins, cytochrome-bcl, translaminar, quasi-systemic, protective, curative, eradicative
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