FIRE BLIGHT ON APPLE: EFFECTS OF WIND AND RAIN IN DEVELOPMENT OF TRAUMA BLIGHT

Trauma blight is a phase of fire blight affecting fruit, leaves, and shoots caused by some type of physical injury to the plant.
It is most often associated with wounds caused by hail.
Less obvious causes of trauma blight are wind, rain, and insect feeding that appear as shoot tip infections.
The goal of this research was to monitor weather parameters and new trauma infections of shoots, and seek correlation between them.
Weather monitors for temperature, relative humidity, rainfall, leaf wetness, wind speed and direction were installed in two sites in western New York state in 1997 and 1998. New fire blight infections on shoots were counted and marked twice per week.
In 1998, weather conditions were identified that occurred approximately 103 cumulative degree days (DD) >55F (57 DD >12.7C) preceding the appearance of infection symptoms.
Preliminary data analysis using simple correlation suggests that the highest correlation with new infections is with the date (-0.745), with lower correlation with temperature (maximum, minimum, and mean), and relative humidity.
More complex analysis using the log of new infections shows stronger correlation with the sample date and relative humidity.
Eventually, this work could help producers make management decisions regarding secondary spread of fire blight.

VIII International Workshop on Fire Blight

D.I. Breth, A. Bentley, M.T. Momol, R.C. Seem, H.S. Aldwinckle

https://doi.org/10.17660/ActaHortic.1999.489.80