ISHS Acta Horticulturae 273: V International Workshop on Fireblight
THREE YEARS OF EXPERIENCE IN CHEMICAL CONTROL OF FIRE BLIGHT IN PEAR ORCHARDS IN BELGIUM |
| Authors: | T. Deckers, W. Porreye, Ph. Maertens |
| Abstract:
The central problem in chemical control of fire blight not only consists in finding good chemical compounds but also in finding an optimal strategy for their application in orchard. During the last 3 years, we evaluated the following compounds : streptomycin sulfate (100 g a.i./ha), flumequine in different formulations (300 g a.i./ha) and S-0208 (300 g a.i./ha). These three compounds are considered to be equally active. Different periods of risk are described for pear orchards under natural infection conditions : primary blossom, secondary blossom, shoot growing period and fruitlet development. During primary as well as secondary blossom periods, chemical protection of the blossoms can be necessary when climatological risk is high. Especially the chemical protection of the primary bloom appears to be essential to prevent a strong further development of the disease. For the prediction of the first fire blight infections during the season in the orchard, the POWELL value of 18 degree days above 18.3°C is a useful treshold value. Later in the season, the BILLING system with SCHOUTEN's corrections of the PD values can indicate periods with high climatological risk. However, chemical control measures should always be combined with measures to reduce bacterial inoculum in and around the orchard. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
