Decision Support Systems for integrated control of late blight

Huub T.A.M. Schepers

Abstract

All definitions for integrated control agree that maximum emphasis should be put on prevention by using resistant cultivars and cultural measures. Moreover, the use of plant protection products should be limited to the essential minimum using Decision Support Systems (DSSs) that integrate and organise all relevant information. Computer-based DSSs that require weather information and regular late blight scouting inputs have been developed and validated in a number of European countries. In the frame of the EU concerted action “European network for development of an integrated control strategy of potato late blight (EU.NET.ICP)” several DSSs were validated in 1999-2001. The overall conclusion was that in most cases the use of DSSs combined a good disease control with a reduction of fungicide input. The DSSs can be used as a PC-version but more and more, parts of information are delivered to users by phone, fax, e-mail, SMS and websites on the Internet. An important task for the near future is to update the DSSs with information on the epidemiology of the new aggressive population of Phytophthora infestans. Issues such as (1) the influence of temperature and relative humidity on the infection process, (2) the role of primary inoculum sources (seed, oospores, volunteers, dumps), (3) the role of secondary inoculum sources (distance, severity), (4) control of early blight and (5) resistance ratings for foliar and tuber blight have to be addressed in order to be able to formulate a robust control strategy that effectively controls late (and early) blight with a minimum input of fungicides.