Plant and Insect Diagnostic Clinic Update - April 23, 2008

Plant Problems

Plant samples received recently have had the following problems:

  • Brown branch tips. The past few weeks we have received samples of concolor fir with brown branch tips, an indication of stress, but no disease or insect problems. Stresses could include poor site conditions, adverse weather, improper planting (too deep or with coiled roots), injuries to the trunk or roots, etc. Stress can be minimized by watering trees deeply during very dry periods, and ensuring that they have mulch over the rootzone. See HHPN March 8, 2006 for more infomration on strees effects on coifers.
  • Needle Drop. We also received a spruce sample with sudden needle drop and one with Stigmina needle cast. Please see the HHPN article from February 2, 2008 for more information on these interesting spruce diseases.
  • Iris Borers. Iris borers are a serious pest of iris. Iris borers are a species of moth. They overwinter as eggs on old iris leaves. In the spring the caterpillars hatch and borrow into the new leaves. The caterpillars feed within the leaves and move downward into the chromes. The damage caused by the iris borers leads to secondary bacterial infections, which makes the chrome all slimy and smelly. See the article in this issue.

Household Pests

  • Last week the clinic received the first clover mite sample of the year. These are a harmless species of mite, except for their tendency to wander indoors in large numbers. Anecdotally, the problem seems to be worse with new sod lawn and seems to go away after a few years.
  • We also received several samples of carpet beetles. Carpet beetles are also commonly called dermestid beetles. These beetles can feed on stored food products, woolens, leather, taxidermy mounts, and other items of animal origin. Often in homes they are feeding on dead insects in the walls of the home. If they are infesting something in the house the best control is to discard the items. If they are feeding on dead insects in the walls, there is no feasible control.
  • Also with warm weather the ants are back. I have noted the return of the carpenter ants in my kitchen. Please see our guide to common ant species. Ants are usually hard to ID to species, so if you do not have a microscope it is probably best to send samples to us.

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