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    Climbers' CornerTree Academy

    Tree Problem Diagnostics: The 23 Questions of Plant Diagnostics


    This workshop is an update of “The 22 Questions of Plant Diagnostics,” this time focusing on the many difficulties encountered with the diagnosis of plant problems. It also features a mystery: Question 23. Plant problem diagnostics is a key to good tree health care management and a precursor to proper and effective arboricultural treatment.  
    Diagnostics is a Socratic process that begins with key questions about the plant: addressing plant identification, what is normal for the plant, and what are the common problems for the plant. It proceeds through a list of systematic questions about signs and symptoms, aspects of the site, information from those who know the plantings best, and a constant asking of the “what else?” question about what might be involved with why this good tree has gone bad.
    This three-hour workshop, modeled on programs we have given at conferences and to nurseries, tree care and landscape companies throughout the U.S., makes extensive use of samples and case studies. Environmental and cultural problems, pests and diseases, herbicide or chemical injuries, and other problems will be addressed. We will also address the problem of diagnostic hubris. The key to diagnostics in understanding the limitations diagnosticians often have and the mistaken lure of being a one-step know-it-all.
    Many a diagnosis has gone wrong because of the failure to properly answer one of the 22 questions, such as the true identity of the plant and whether what is seen is normal or abnormal for that plant, or whether the “common problems” question is trumped by a new problem. The only truly sure-fire rule of plant problem diagnostics: there are no sure-fire rules. But asking the 23 questions is a big help.      


    Jim Chatfield is an Associate Professor and Extension Specialist for Ohio State University Extension. His focus is on community forestry, plant pathology, plant problem diagnostics, and tree selection research. He holds an M.S. degree in plant pathology from Ohio State University and is the President of the International Ornamental Crabapple Society.

    Joe Boggs, Erik Draper, Amy Stone, and Curtis Young also are professors with Ohio State University Extension, teaching and writing on arboriculture, entomology, plant pathology, horticulture, urban forestry, plant problem diagnostics, tree selection, and community forestry topics throughout the country for the last three decades.

    Climbers' CornerTree Academy

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