A COMPUTER PROGRAM BASED ON BILLINGS SYSTEM 1 FOR TIMING OF CONTROL MEASURES AGAINST FIRE BLIGHT

Billing’s system l has not been devised to be used as a spray warning system.
Nevertheless, it could provide suitable basis for such a system, as soon as reliable weather forecasts of suitable meteorological data are available.

A tentative computerized system is proposed, based on the analysis of climatic data and inoculum potential during 3 distinct consecutive periods :

1. climatic data are computerized daily, to provide informations on the climatic potential of the disease (PD 9 days, rank of incubation periods, infection days…). Some of these informations are general for all 3 periods, others are specific for each of them.

   • forecast for climatic factors considered to be of importance for each period can be included daily, and their consequences for the potential of disease are calculated,

   • then, the climatic risk is rated (from 1 to 6).

2. the local inoculum is estimated according to the past history of the disease in the surroundings, and rated (from 1 to 5).

3. a combination of these ratings for these 3 periods allows a graded warning (no action, observation and pruning out of symptoms, spray) which remains to be adjusted to local conditions (varieties, growing conditions, vicinity of inoculum sources).

IV International Workshop on Fire Blight

C. Jacquart-Romon, D. Payen, J.P. Paulin

https://doi.org/10.17660/ActaHortic.1987.217.17