Many of the apple and pear cultivars grown today are susceptible or highly susceptible to fireblight.   Fireblight, caused by the bacterium Erwinia amylovora, seriously limits apple and pear production in most fruit-growing regions of the United States. During epidemics, financial losses due to lost yield and tree death, can exceed tens of millions of dollars. Fireblight disease is particularly difficult for growers to manage, and the situation is exacerbated by three major problems: Many of the popular cultivars grown are either rated as susceptible or highly susceptible to fireblight; Many of the popular dwarfing apple rootstocks ­utilized are also […]