CLIMATIC ASSESSMENT OF THE RISKS OF FIRE BLIGHT AT BLOOM
Billing's system 1, tried out in different locations in France, over several years, gives a good assessment of the activity of the disease during the main blossom period of the host plants. A theorical pear blossom period is established for c.v. Passe Crassane, using Bidabé's system, taking into account winter and spring temperatures ; some climatic criteria derived from the thresholds of Billing's system are proposed, in order to assess fireblight risks in France during this period.
JACQUART-ROMON, C., PAULIN, J.P. and PAYEN, D. (1984). CLIMATIC ASSESSMENT OF THE RISKS OF FIRE BLIGHT AT BLOOM. Acta Hortic. 151, 129-136