Plant and Insect Diagnostic Clinic Update - September 26, 2012

The following are highlights and updates about samples and questions recently received in the Plant & Insect Diagnostic Clinic.  Visit the PIDC’s facebook page to ask questions and for updates and more pictures.


Yellowjacket wasps are becoming more apparent as the season progresses.  See the Clinic website for more details on recognition and control.

For information on spiders, including those large wolf spiders that are common accidental invaders in the fall, see ISU Extension & Outreach pamphlet PM 1722, Common Spiders in and Around Homes, revised with new color photos, July, 2012.

We have received a couple of samples of backswimmers and water boatmen. These neat aquatic insects are attracted to lights at night and can sometimes be found in large numbers. Be careful handling backswimmers, they can inflict a painful bite. For more information and pictures please see their pages on BugGuide - backswimmers and water boatmen.

Speaking of painful bites…this is the time of the year when minute pirate bugs make their tiny presence known by biting us. Most of the year minute pirate bugs happily feed on pests in our gardens, but in the fall as plants dry out on prey become scarce they fly around more, land on us, and check to see how we taste. They don’t feed on humans and are harmless except for allergic reactions to the bites. For more information and a picture please see our Clinic website.

Disease update

The season is winding down yet some samples are still coming in. The last couple of weeks we have seen several arborvitae showing browning of needles. None of them have shown signs of disease or insect damage and symptoms are most likely related to hot and dry weather conditions observed this year.

We have diagnosed a lot of bur oak blight (BOB) lately and one of the samples also showed oak wilt symptoms.

We have not received many veggies or ornamental samples but it’s time to start thinking about cleaning up your garden for next year. A thorough fall cleanup can dramatically reduce plant disease problems next year. For more information check this article.


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