Management of apple scab (Venturia inaequalis) in Romania based on electronic warnings

Apple scab, Venturia inaequalis (Cke) Wint., is a major problem in Romanian apple orchards and is responsible for serious economic losses. The purchase of spraying equipment and phytopharmaceutical products is very expensive in comparison to the income of local apple growers. This is one of the reasons why reduced fungicide sprayings are becoming more and more important. That's why a project was started to investigate the influence of West-European control measures and to improve interaction between local apple growers and research facilities. This experiment took place in an orchard of the university of Timisoara (USABT), where occurrence of apple scab was very high, and in a well managed commercial orchard, both in the Banat region. In July 2006, a comparative study between a traditional Romanian management program, a calendar-based program and a computerized weather-based management program was conducted. Four test plots were taken. The sprayments in plot 1 happened according to the integrated computerized model. No sprayings took place in plot 2. In plot 3 were some sprayments done with sulphur according to the traditional Romanian program. The sprayings in plot 4 were done following a calendar-based spraying program. The products that were used for the sprayments were all easy to obtain in Romania such as dodine (Sillit flow), dithianon (Delan flow), difenoconazole (Score), pyrimethanil (Scala), metiram (Polyram), kresoxim-methyl (Stroby). The occurrence of scab in plot 1 was very low in comparison to the other plots. Analysing the data, on average, the treatments done in plot 1 caused about 50% less damage than the traditional sprayings. This indicated that with a relative small amount of well timed sprayings a enormous amount of damage can be prevented. A calendar-based management program seems to be less effective (more sprayings needed and the results are worse). These results also emphasize the importance of the development of an adequate apple scab management program that should be presented to local apple growers.