First Examinations to date the exactly Time of Infection of Sooty Blotch

Summary

Sooty blotch disease caused by a complex of different funghi. The incidence and severity of these disease are dependent on moisture and temperatur conditions during the summer months. A great problem is to fix the exactly ti me of infection. If this would be possible the threaten apple orchards could be better controlled by plant protection.
To date the exactly ti me of a possible infection, the apple fruits were wrapped in plastic films during the growing season. After full flower the fruits were bagged on various dates and kept covered until harvest.
The first symptoms of sooty blotch disease appeared in the apple orchard at 17 July 2000. If the time of infection is dated 2-3 weeks bevor the first symptoms appeared, so the infection could be placed to 26.127. June 2000. Between the 26. 06.2000 and the 17 July 2000 the weather conditions had been favorable for the sooty blotch disease. During this peri od we bagged fruits on four different termi ns. After harvest we placed the fruits in a moist chamber for 10 days. During this time it was possible to develop sooty blotch symptoms on the fruit surface. Ali of those fruits were affected with sooty blotch symptoms. Fruits befor this termin didn't show any symptoms. This would mean, that the first infection in 2000 took piace in late June and not earlier.