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As more people add pears to their gardens , this situation may change . At the present time , no such data sets exists , and no system is in place to provide it . Powdery mildew can be a serious foliar disease in some years and some locations ; for control of powder mildew or another specific insect or disease pest , contact your county extension office . Clearly , space-based observations would be valuable . Only a few of these events would result in a disaster , but all would be of essential scientific interest if we are to make significant progress in understanding the earthquake cycle .