Plant and Insect Diagnostic Clinic Update - May 7, 2008

Plant Problems

  • Discolored conifers. The past few weeks the clinic has received numerous samples of spruce, arborvitae and concolor fir with symptoms of stress. Common symptoms include discolored needles or browning of the tips of needles. These symptoms are the same as some needle diseases so we examine each sample for signs of a fungal pathogen. Winter is a stressful time for evergreens and the long cold spring seems to have adversely affected some plants. If it is environmental stress we recommend homeowners wait and see how the tree progresses and hope that the new growth is healthy and the tree grows out of the damage. See HHPN March 8, 2006 for more information on strees effects on conifers.
  • Mid- to late May is the best time to control many of the scale insects found on ornamental plants in Iowa. See the article in this week's newsletter.

Plant Indentification

  • Spring has also brought in a large number of plants for identification. Now is a good time to determine just exactly what is coming up in your yard, garden and landscape. Plant identification is a free service offered by the Clinic in cooperation with the ISU Departments of Agronomy and Horticulture. Submit plants and weed samples for identification to the Clinic, enclosing either Plant ID form (SP-258) or Weed ID and Herbicide Injury Diagnosis form (Ag-146). All samples can be mailed to the new combined Clinic (your one-stop-shop!), 327 Bessey Hall, ISU, Ames IA 50011.
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