Jon shows us how to deal with Mexican Bean beetle pests on a mature crop of beans.

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Hi, I'm John Traunfeld with the University of Maryland Extension. Garden bush beans are one of the easiest vegetable crops you can grow. I'm going to share a technique today called destructive harvesting and it accomplishes two goals. It enables you to get old declining bush bean plants out of the garden, open up the garden for new seeds. And it also helps us take care of one of the major garden pest of bush beans. And that's the Mexican bean beetle. So these are some of the plants I pulled out of my garden last night and I just pulled them right out by their roots. I held them upside down and I stripped the remaining beans off the plants. There were some large pods and some pencil thin pods. After I pulled all the beans off, I got about three pounds of beans. I took a big black trash bag and I stuffed the bean plants in the bag, tie the bag off and let it sit out in the sun because there is a lot of Mexican bean beetle activity on these plants.

And you can see we have some adults left. We have some immatures that are feeding and even some egg masses that are remaining on the plants. So we want to get rid of that pest by putting it all in the trash bag and letting them cook for awhile. One other neat thing, when you pull the plants that you can see the tiny nodules attached to the roots, and these are formed by rhizobia bacteria that are living in a symbiotic relationship with the bean plants. They get nutrients from the bean plants to continue their life cycle, and in return, these bacteria help the bean plant fix nitrogen from the air that will become available to the plant. So beans, of course, are in the group of plants known as legumes, and they can do this miraculous thing fixing nitrogen with the help of bacteria.