EVALUATION OF THE MARYBLYT^™ MODEL FOR PREDICTING FIRE BLIGHT BLOSSOM INFECTION IN NEW ZEALAND

The MARYBLYT^™ computer model, Version 4.1, was evaluated for predicting fire blight blossom infections for the 1994–95 growing season in apple and pear orchards in the Waikato and Hawke’s Bay regions of New Zealand.
During the main flowering period in October 1994, weather conditions did not favour infection, no infection events were predicted and blossom blight was not observed in the monitored orchards.
The MARYBLYT^™ model appears to be less accurate in predicting infection events on pear trees as symptoms occurred earlier than predicted.
However, the infection events and occurrence of blossom blight symptoms on Royal Gala and Braeburn trees from both regions were accurately predicted.
In these orchards, disease symptoms were found only after the occurrence of infection events in November.
All of the 4 and 5 infection events in Hawke’s Bay and Waikato orchards respectively were accurately predicted because blossom blight symptoms occurred either on the day or within a day of the dates they were predicted to appear.
Outbreaks of blossom blight in the Royal Gala and Braeburn blocks were caused by presence of late blooms and conditions which favoured fire blight infection.

VII International Workshop on Fire Blight

S.C. Gouk, R.J. Bedford, S.O. Hutchings, L. Cole, M.D. Voyle

https://doi.org/10.17660/ActaHortic.1996.411.24