Urban trees are susceptible to many pathogenic fungi and bacteria that uncontrolled can result in high mortality rates. Control of these diseases is primarily through the use of agrochemicals. Increased pathogen tolerance to commercially available agrochemicals and increased legislative restrictions regarding the use and application of agrochemicals means new techniques of disease control are of importance. Systemic induced resistance (SIR) is the phenomenon whereby a plant's own defense mechanisms are induced by prior treatment with either a biological or chemical agent. Recent developments in disease control have led to the formulation of a range of commercially available SIR inducing compounds. Studies using SIR inducing compounds have found several to be highly effective in controlling fungal, bacterial and viral leaf and root pathogens. Where studied a “one off” application has been shown to provide long lasting, broad spectrum disease control equal to conventional 8-10 spray applications.

 This talk will summarise Hyland Johns funded research concerning the efficacy of SIR inducing compounds on enhancing disease resistance against apple scab and Armillaria spp, important foliar and root biotrophic pathogens frequently encountered in urban environments. Areas of discussion include: 

 The importance of timing of SIR application i.e. can SIR inducing compounds be applied as therapeutic and/or preventative control measures

 The most effective dose rates and frequencies of application to achieve pathogen control

 The most plant response method of application (drench, foliar spray and stem/trunk injection)

 The practicalities of these results for other sectors of the arboricultural, horticultural and landscape industry.