Bean Leaf Beetle

I have a new surprise in the garden this year.  The bean leaf beetle has arrived. I've never had them before but my bean patch has suffered a lot of damage from them. One morning I went out and my bean plants were riddled with holes. These little beetles are only about an eighth of an inch long but they are very hungry.

Interestingly they come in different colours. The one in the top photo is almost beige with black, and the one in this photo is a deep maroon with black.  Some of them are more brown with black. I have been picking them off and dispatching them, but they are sneaky little guys. Any disturbance to the leaf and they instantly drop to the ground. I put one hand under the leaf and then when I touch the leaf I usually can catch the dropping beetle.  Not always successful.  Sometimes just the approach of my hand will make them disappear.

From the state of the mangled leaves, you would think there are lots of them but actually I probably only saw about 10 of them when I first noticed the damage (the patch is about 4' x 4'). The numbers are going down so I am optimistic that I can deal with them. From what I read, they are most active at this time of year and then die after laying eggs later in the season.  I have a single bean plant about 20 feet away from the main patch and it has no damage at all so they don't seem to move around much which makes you wonder how they came here to begin with.

So there you have it:  the bean leaf beetle. I hope you never make their acquaintance.

Happy gardening.

Postscript:  After dutifully picking off the beetles for about 3 weeks, they went away.  It is their natural cycle to lay eggs around now but I don't think many of them were around to lay eggs.  The plants are big and healthy now (July 9) and I am harvesting a good supply of beans.