Articles
HOW TO OPTIMIZE THE VENTURIA PIRINA INOCULATION ON PEAR LEAVES IN GREENHOUSE CONDITIONS?
Article number
800_124
Pages
913 – 920
Language
English
Abstract
Pear scab is an important disease in pear orchards.
A programme for breeding new cultivars resistant to this pathogen is in progress.
The breeders must test the resistance of new hybrids to Venturia pirina in greenhouse conditions.
In our conditions, numerous works have been undertaken over the last ten years to optimize the systems of inoculation, to assess the resistance levels and to study new strains of V. pirina. The experiments are undertaken on seedlings or grafted pear cultivars grown in greenhouse conditions.
The inocula are prepared from conidia suspensions or scabbed leaves; the conidia from scabbed leaves are more homogeneous and reactive.
Compared to apple scab, there are numerous failures when inoculating and results are very heterogeneous.
One principal inhibition is caused by phenolic compounds.
Inocula prepared from scabbed leaves are often ineffective.
The leaves of pear release phenolic compounds in water; in the open air, these compounds become oxidized and have a fungicide action.
The conidia germination is inhibited and the experiments are impossible.
Studies were performed on the kinetics of the phenolic compounds release and the effect on conidia germination.
The best conditions to prepare the inoculum were determined.
The use of an antioxide compound has been envisaged; among the tested compounds, ascorbic acid gave very interesting results.
Another strategy is to try to avoid the V. pirina multiplication phase on pear seedlings.
The in vitro method of culture of the fungi on cellophane film gave very good results.
Currently, in our conditions, we can obtain good regularity of inoculation conditions, similar to apple scab inoculation.
A programme for breeding new cultivars resistant to this pathogen is in progress.
The breeders must test the resistance of new hybrids to Venturia pirina in greenhouse conditions.
In our conditions, numerous works have been undertaken over the last ten years to optimize the systems of inoculation, to assess the resistance levels and to study new strains of V. pirina. The experiments are undertaken on seedlings or grafted pear cultivars grown in greenhouse conditions.
The inocula are prepared from conidia suspensions or scabbed leaves; the conidia from scabbed leaves are more homogeneous and reactive.
Compared to apple scab, there are numerous failures when inoculating and results are very heterogeneous.
One principal inhibition is caused by phenolic compounds.
Inocula prepared from scabbed leaves are often ineffective.
The leaves of pear release phenolic compounds in water; in the open air, these compounds become oxidized and have a fungicide action.
The conidia germination is inhibited and the experiments are impossible.
Studies were performed on the kinetics of the phenolic compounds release and the effect on conidia germination.
The best conditions to prepare the inoculum were determined.
The use of an antioxide compound has been envisaged; among the tested compounds, ascorbic acid gave very interesting results.
Another strategy is to try to avoid the V. pirina multiplication phase on pear seedlings.
The in vitro method of culture of the fungi on cellophane film gave very good results.
Currently, in our conditions, we can obtain good regularity of inoculation conditions, similar to apple scab inoculation.
Publication
Authors
M. Chevalier, M. Tellier, Y. Lespinasse, V. Caffier
Keywords
pear scab, inoculum, phenolic compounds, antioxide compounds
Online Articles (151)