July 28, 2017

Plant and Insect Diagnostic Clinic Update – July 28, 2017

Bed bug and bat bug.


Marssonina Leaf spot symptoms. 
Photo credit: Lina Rodriguez Salamanca, Iowa State University Plant & Insect Diagnostic Clinic.
 

Potato Defects


When harvesting potatoes, home gardeners occasionally come across tubers with defects.  Some commonly encountered problems are listed below.

Knobby Potatoes

Knobby or deformed potato tubers develop when tuber growth is halted by drought, high soil temperatures, or some other factor.  When growth resumes, tubers become knobby or misshapen.  Watering on a regular basis (about once a week) during dry periods helps prevent this problem.

It’s Spotted Wing Drosophila Time Again

Spotted wing drosophila adult fly on raspberry

The spotted wing drosophila (SWD), Drosophila suzukii, is found in most areas of Iowa and is a pest of fruit, especially, raspberry, blackberry, blueberry, grape, aronia, strawberry and possibly tomato and apple.

Late summer is the time populations are most noticeable and when damage occurs to one of their favored crops, fall-bearing raspberries.  Growers and gardeners should be monitoring for SWD and be prepared to manage this pest through harvest.

The following resources are recommended.

Emerald Ash Borer Confirmed in Ringgold County


The emerald ash borer (EAB), has been confirmed in Ringgold County, making it the 52nd county in Iowa where this highly destructive insect has been found.  Read more about the most recent confirmation of EAB in Iowa in the Iowa State University Extension & Outreach news release from July 27, 2017.  The current confirmed distribution of EAB in the state is indicated in the map below and online at https://hortnews.extension.iastate.edu

Handling Problems with Landscape Trees


Suckers, sloughing bark and galls are common issues seen on trees in mid-summer.  Read more about these problems and what to do about them in the Iowa State University Extension & Outreach Yard & Garden news release from July 27, 2017.

Harvesting, Drying and Storing Onions


Onions are easy to grow in the home garden but there are important details to know on when to harvest and how to dry and store them for best results.  Read more in the Iowa State University Extension & Outreach Yard & Garden news release from July 19, 2017.