Potato Bugs

July 8, 2010 0 Comments

Lynne sent me an email saying that she has a wonderful patch of potatoes but has some bugs on them.  She called them potato bugs and that brings up an image of the Colorado Potato Beetle.

Colorado Potato Beetle. Image from Duke University.

However, there is also an insect called the potato leafhopper.

Potato Leafhopper

Potato Leafhopper adult and nymph.

It is probably the beetle since the leafhopper relies on the wind to get to where it is going.  It cannot survive our winters and gets blown in on the wind, so where it lands is where it eats.

The Colorado Potato Beetle, however, is common in Iowa’s home gardens.  They are about 3/8 of an inch long and have an oval body.  If you care to count, there are ten alternating black and yellow stripes on the wing covers.  Hmm.  Must be a Hawkeye fan. 

The adults hide in wooded areas and other protected locations for the winter and begin laying eggs on host plants in early spring.  These host plants include potato, pepper, eggplant and tomato. The eggs hatch into dark  red, humpbacked larvae with dark heads and two rows of black spots on the sides of the abdomen.

Potato Beetle larvae

The larvae often feed in groups and cause isolated severe defoliation.  When the larvae grows to 1/2 inch in length, they burrow into the soil to transform into the adults that appear in mid-summer to repeat the cycle. 

The beetle is difficult to control.  Hand picking may be the best method as long as you don’t have a whole field of potato plants.  If you decide to use an insecticide, complete and thorough coverage of the infested plants is necessary for good control. Liquid sprays are usually more effective than dust applications.  Now, these bugs have been around for a long time and decades of repeated insecticide use, the beetle has developed a resistance to some insecticides, including Sevin.  If Sevin doesn’t work, try Eight, also called permethrin, or bifenthrin, kaolin clay (Surround) or azadiractin (Neem).  You can also utilize Mother Nature.  The Predaceous stink bug feeds on Colorado potato beetles.  Just make sure you don’t step on them!

Predaceous Stink Bug

I wouldn’t go out and recruit a bunch of these, however.  They will also eat monarch caterpillars.

To help control the Colorado Potato Beetle, examine plants early in the spring for these beetles.  If they are found, the undersides of the leaves should be looked at to see if there are any eggs.  Also check for larvae.  You should only use the insecticides if the insect populations are large enough.  Otherwise, you will just have to pick them off and drop it into a container with detergent and water.  The Extension office at the University of Maine even suggests using a hand held vacuum cleaner.  Hmmm.  If you do either of these every 2 to 3 days, all the Colorado potato beetles life stages should be removed. 

I am picturing a run on hand held vacuums…. I call dibs!

Dig it!

Filed in: Pests

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