When we started farming I was introduced to many new insect pests that I was not aware of as a home gardener. One that took us by surprise was the Mexican bean beetle. These little yellow creatures can wreak havoc on bean plantings, but are usually worse for growers who succession plant beans. Our second year growing beans in our field was pretty much a disaster by the time August rolled around. At that point any bean planting that germinated was devoured by these beetles and the sheer amount of bean beetles was quite impressive.
The problem arises when we succession plant beans. This means that we plant beans weekly or bi-weekly to ensure a marketable crop that we can sell every week from June until the first frost in October. The adult bean beetles overwinter and emerge in the spring and begin lightly feeding on the leaves of the plants. That does not cause a problem for the first crop of beans. These adults lay eggs on the bean leaves and when these eggs hatch the baby bean beetles feed heavily on the leaves for a couple weeks. As they grow they fly to the next crop of beans, mate and lay more eggs. This continues week after week until the population of bean beetles becomes out of control and by the time mid-August rolls around it becomes impossible to continue to plant and grow beans.
The year after I first saw the problem, I figured we had to do something to control it. My initial attempt at controlling it was to torch every bean bed after it was harvested for two weeks. I figured by torching the bed I would kill many of the young bean beetles that were not able to fly to the next bed. This worked to some extent, but the population of bean beetles would still become unmanageable by September. Then I ran across an article about a technique that bean growers were using in New Jersey. They were conducting studies using a parasitic wasp called Pediobus Foveotatus and having successful results.
We adopted this technique and it has worked very well for many years now. We wait until we see the first set of yellow eggs underneath the bean leaves. As soon as we spot them we order the parasitic wasps and have them shipped as quickly as possible. They come in the form of mummies (picture below shows a mummified bean beetle on the underside of a bean leaf). We hang the mummies in the middle of the row of beans and wait. In a couple days the parasitic wasps hatch and we hope it times up with the bean beetles hatching from their eggs. If it does, the wasps will lay eggs inside of the bean beetles (a bean beetle is shown on my arm in the picture below). In another couple of days, the bean beetles turn into a brown mummy because the parasitic wasp eggs have hatched and eat the bean beetle from the inside out. They then fly and lay eggs on other bean beetles.
This occurs throughout the season with every planting of beans. Each week as the bean beetles try to multiply, they are parasitized by the wasps and the number of wasps grows to large enough numbers to wipe out enough bean beetles so that they damage the crop less and less as the year goes on. We cannot rely on the parasitic wasp being present in our environment because it will die in the winter time. This is why we have to purchase them each year. This has definitely become one of the best purchases we make every year and I would recommend it to any grower having difficulty with bean beetles.
This week's share consists of:
Full Share- beans, cucumbers, cherry tomatoes, tomatoes, zucchini, scallions, eggplant, green kale, parsley, celery, fingerling potatoes
Half Share- beans, cucumbers, cherry tomatoes, tomatoes, zucchini, scallions, eggplant
What can I make with my share this week?? Here are a couple of ideas!
Impossibly Easy Zucchini Pie- I use this recipe all season and change up the vegetable based on what's in season. http://www.bettycrocker.com/recipes/impossibly-easy-zucchini-pie/aba1e434-a8aa-4da3-9d13-7a3505e40a97. Here's my favorite recipe for homemade bisquick too! http://penniesandpancakes.blogspot.com/2013/04/homemade-bisquick-mix-010-per-cup.html#.VbWFT_lViko
Browned Butter Roasted Beans- Preheat the oven to 375 degree. Wash and snap the stems off of the beans and put in a larg mixing bowl. Melt 1 tablespoon of butter and pour over the beans. Sprinkle 1/2 teaspoon of garlic powder on the beans and mix to coat the beans with butter and garlic. Spread the beans in a thin layer on a cookie sheet or glass baking dish. Mix 1/3 cup of panko breadcrumbs, 1/4 cup parmesan cheese and 1 tablespoon of italian seasonings together and sprinkle on top of the beans. Roast the beans for 15-20 minutes or until the beans are tender and the bradcrumbs turn golden brown.