Articles
INDUCTION OF PLANT DEFENSE REACTIONS ON FRUIT TREES AS PART OF A FIRE BLIGHT CONTROL STRATEGY IN THE ORCHARD
Article number
896_78
Pages
531 – 540
Language
English
Abstract
During the last years, different new molecules have been developed for fire blight control with the aim to induce defense reactions in the fruit trees before a fire blight infection occurs.
These plant defense enhancing (PDE) molecules have no bactericidal properties and should be applied preventively prior to fire blight infection.
For the protection of a blossom period (primary or secondary bloom), the treatments with PDEs should start during the phenological stage of green bud stage (BBCH 56), followed by a treatment during the early white balloon stage on pear or during pink bud stage on apple (BBCH 57). The final treatment should be timed at the beginning of bloom (BBCH 61). The time interval between the treatments can vary as a function of the development rate of the phenological evolution of the blossoms.
The interval should be around 7-10 days for the primary blossom protection, but can be shorter when temperatures are higher during the secondary bloom period.
Plant defense inducing molecules interfering with blossom infections are not always active in the prevention of shoot infections and vice versa.
For fruit infections on apple and pear, we have seen a substantial reduction in infected area and in bacterial ooze formation when the trees were preventively treated with fosetyl-Al.
This reduction in ooze production on fruits is considered to be a very interesting factor in the fire blight epidemiology, because it can help to reduce the buildup of a high bacterial inoculum in the orchard.
Finally, the induction of an abiotic stress in fruit trees by repeated treatments of heavy metals like Cu, Mn and Zn can result in an induction of a plant defense reaction and can be helpful in a fire blight control strategy under orchard conditions.
These plant defense enhancing (PDE) molecules have no bactericidal properties and should be applied preventively prior to fire blight infection.
For the protection of a blossom period (primary or secondary bloom), the treatments with PDEs should start during the phenological stage of green bud stage (BBCH 56), followed by a treatment during the early white balloon stage on pear or during pink bud stage on apple (BBCH 57). The final treatment should be timed at the beginning of bloom (BBCH 61). The time interval between the treatments can vary as a function of the development rate of the phenological evolution of the blossoms.
The interval should be around 7-10 days for the primary blossom protection, but can be shorter when temperatures are higher during the secondary bloom period.
Plant defense inducing molecules interfering with blossom infections are not always active in the prevention of shoot infections and vice versa.
For fruit infections on apple and pear, we have seen a substantial reduction in infected area and in bacterial ooze formation when the trees were preventively treated with fosetyl-Al.
This reduction in ooze production on fruits is considered to be a very interesting factor in the fire blight epidemiology, because it can help to reduce the buildup of a high bacterial inoculum in the orchard.
Finally, the induction of an abiotic stress in fruit trees by repeated treatments of heavy metals like Cu, Mn and Zn can result in an induction of a plant defense reaction and can be helpful in a fire blight control strategy under orchard conditions.
Publication
Authors
T. Deckers, H. Schoofs, W. Verjans, R. Valcke, K. Vrancken
Keywords
fire blight, Erwinia amylovora, plant defense, fosetyl-Al, heavy metals
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