Plant and Insect Diagnostic Clinic Update - June 15, 2011

News Article

The following are highlights and updates about samples and questions recently received in the Plant & Insect Diagnostic Clinic:
 
Insects

Wet weather and warm nights combine to give an advantage to millipedes that migrate by the millions overnight, wandering into homes, garages and landscapes.  There still is no silver bullet for millipede prevention.  Perimeter barriers of insecticide around the house or other building must be very large to accomplish any protection.  None of our residual insecticides kill millipedes quickly enough to "drop them in their tracks" after crossing an insecticide barrier of only a few inches next to the house.  See our website more more details.

We are in the time of the year when we could expect to see emerald ash borer adult beetles if they were present.  So far, only tiger beetles (see photo below) and other shiny green insects have been reported.  For a review of insects that resemble the emerald ash borer, see this page from the University of Minnesota.

Diseases

Oak tatters has been common this spring.  Oak tatters looks very similar to caterpillar damage, but is actually caused by exposure to herbicides.  When developing oak leaves are exposed to very low amounts of  herbicides (acetochlor (with atrazine) and s-metolachlor)  this tattered appearance occurs later as the leaves expand.

The sixspotted tiger beetle can be distiguished from the emerald ash borer by the thorax that is narrower than the head and the abdomen.

The six-spotted tiger beetle (shown) can be distinguished from the emerald ash borer by the thorax that is narrower than the head and the abdomen.

 

Symptoms of oak tatters.

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