IntroductionPlant diseases cause economical loss of billions of dollars byreducing crop yield, lower produce quality and contaminating foodgrain with toxic chemicals (Guo et al., 2013). The endless varietyand complexity of the many diseases of plants caused by fungihave led to the development of a correspondingly large number offungicides; unfortunately several plant pathogens have developedresistance to certain fungicides (Agrios, 2005). Another approach isto apply genetically resistant cultivars, but this is not viable after afew years (Fry, 2008).