2009 Annual Report 1a.Objectives (from AD-416) To screen crape myrtle germplasm for host plant resistance to Cercospora Leaf Spot (CLS) and powdery mildew. Emphasis will be placed on maintaining ermplasm under ambient field conditions and other horticultural necessities. 1b.Approach (from AD-416) Crape myrtle controlled crosses and commerical clones will be placed at the cooperator's location and will be screened for CLS and powdery mildew. Evaluation will be made by the cooperator and by ARS scientists throughout the evaluation season each year. Germplasm with host plant resistance will be tested further in subsequent experiments. 3.Progress Report Over 2,000 crape myrtle seedlings composed of 26 families generated from 11 commercial clones were screened for field resistance to powdery mildew and cercospora leaf spot for two seasons at Auburn University’s Brewton field station for two growing seasons. Disease pressure for both diseases was adequate in both seasons to separate seedlings and select individuals displaying resistance to both diseases. Approximately 110 seedlings were selected and moved to a new plot for additional evaluation with a tree spade. The ADODR or his representative meets regularly with the cooperating scientist, and these meetings include site visits.