0
points
What are these bugs on my bean plants?

Bean    None Given

These are on my bean plants. What are they? Look like ladybug. Could they be causing these holes?


Posted by: Camille (1 point) Camille
Posted: May 18, 2016


Dalton Ludwick commented,
I'm going to have disagree with the comments below. This insect appears to be bean leaf beetle (Cerotoma trifurcata). You can tell by the black triangle on the wings and four spots. I have included an article that describes the damage and life cycle of this insect. Depending on the numbers and amount of defoliation, control may be needed. I realize this is much later than when you posted but proper identification is important for management. https://extension.entm.purdue.edu/fie... http://www.extension.umn.edu/garden/i...
almost 3 years ago.

Matt Borden commented,
Oh wow, great observations Dalton. I'll have to remember that ID feature in the future. Thanks!!
almost 3 years ago.



Answers

2
points
Yes, the damage is from the beetle you have in the picture, it is a spotted cucumber beetle, Diabrotica undecimpunctata. These can be extremely destructive beetles and have a wide range of crops they feed on, but beans are favorites for the early season.

-Edit- see Dalton's comment regarding the triangular shape at the scutellum.


Posted by: Matt Borden (4 points) Matt Borden
Posted: May 19, 2016




0
points
Yes, this is the Spotted cucumber beetle adult Diabrotica undecimpunctata
Edit Nov 30th 2016- see Dalton's answer which seems to me more accurate

How many do you have and what control are you interested in. For example, if you absolutely do not want to use chemicals then let us know and we can advise. If you want chemicals we can offer advice on that too.

Also, do you have any cucumbers or other cucurbits growing nearby?


Posted by: David Hughes (43 points) David Hughes
Posted: May 19, 2016


Heidemarie Hertenstein commented,
I seem to have the same problem, and yes there are cucumber plants not far from my beans. What remedies could you recommend?
over 3 years ago.



0
points
I'm going to have disagree with the comments below. This insect appears to be bean leaf beetle (Cerotoma trifurcata). You can tell by the black triangle on the wings and four spots. I have included an article that describes the damage and life cycle of this insect. Depending on the numbers and amount of defoliation, control may be needed. I realize this is much later than when you posted but proper identification is important for management. https://extension.entm.purdue.edu/fie... http://www.extension.umn.edu/garden/i...


Posted by: Dalton Ludwick (1 point) Dalton Ludwick
Posted: December 1, 2016




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