Botrytis spp. and diseases they cause in agricultural systems - An introduction

Some leading characteristics and historical notes on Botrytis spp. are described here. Botrytis spp. infect many host plants in all climate areas of the world, infecting mainly upper plant parts at preand post-harvest stages. Bulbs, seeds and other propagation material also suffer infection. Infection can occur in high humidity in the presence or absence of water films. Infection may be quiescent, aggressive, restricted or widely developing. The production of high numbers of conidia poses a long lasting threat to susceptible hosts. Genotypic and phenotypic variation is most important in the broad spectrum pathogen B. cinerea. Moreover, changes in populations in response to selection by exposure to xenobiotics, especially fungicides, are quite common in the genus and fungicide resistance has been recorded in Botrytis populations throughout the history of the modern fungicide era. Detailed studies on the precise conditions that promote infection, disease development and survival of inoculum have provided the essential epidemiological information required for design of control strategies. For example, cultural methods have been developed that increase aeration and drying of the plant canopy to reduce the risk of Botrytis epidemics. The increasing requirement for alternative approaches to reduce farmers' dependency on use of fungicides led to the evaluation and exploitation of potential biocontrol agents capable of substantial disease suppression in a commercial context, and within integrated crop management systems. © 2007 Springer Science+Business Media B.V