The greatest limitation in pear production in central Texas is a bacterial disease known as fire blight.  As a rule, European pear varieties such as 'Bosc', 'D' Anjou' and 'Bartlett' are extremely sensitive to fire blight and commonly die a year or two after planting.  Varieties derived from P. userensis exhibit considerably greater resistance to fire blight.  Caused by the bacterial pathogen Erwinia amylovora, fire blight can infect trees through flowers and pruning cuts.  Once infection occurs, the bacterium multiplies and moves systemically through the vascular tissue of the tree.  Even varieties that have some resistance can become infected, but the disease is usually not fatal to the tree.  If a tree becomes infected, the general recommendation is to prune out infected tissue to reduce the risk of spreading throughout the tree.  Infections should be pruned approximately six inches below where symptoms appear and pruning shears or saws should be sterilized with a 2% chlorox solution between cuts.

Old standard fire blight resistant varieties such as 'Kieffer', 'Garber' and 'Orient' are easily grown, but have considerably lower fruit quality than European types.  The flesh of standard fire blight resistant pears do not have a smooth fruit texture, but have a high concentration of "grit cells".  This gritty texture is a detriment to in-hand eating quality, so consequently these varieties are commonly used for cooking and canning. Hybrids between the two species have resulted in varieties that have intermediate fire blight resistance and increased fruit quality.  'Ayers' and 'Warren' have a history of good production in the Hill Country, have a smooth, melting flesh and withstand fire blight with proper care.