The potatoes in our field are happy and growing well. They have developed a nice foliage by now, so this means that it is time for the Colorado Potato Beetle to appear and enjoy eating delicious leaves! These beautiful beetles are a threat to potatoes in many parts of the world. They devour the plant and so the potatoes themselves get no force anymore to develop. This week we found the first beetles of this season on our plants and our counter attack has started. The adults come out of the soil once the potato plants have sprouted. They eat the leaves and mate. The female lays hundreds of eggs which results in hundreds of potato leaf-hungry larvae. When big and fat, the larvae fall and bury themselves in the ground, where they pupate and become adult. Depending on the climate, there will be one to three of these cycles per year.
Following are a few possibilities for an organic counter attack:
- We follow the technique of our Dutch friend and organic CSA farmer Wouter, which means picking them by hand, on a regular basis, and then crushing them quickly.
- Another option is to get some ducks and let them loose in the potato field. Ducks like the beetles and will keep them under control. Chickens are normally less fond of them and also will do more harm to the plants with their scratching behavior. (Ducks are used for the similar purpose in gardens for slug control, and can be wonderful egg producers at the same time.)
- A local farmer told me that he always plants a garlic clove with every potato and has never had problems with the beetles. Worth a try.
- Also planting dill with the potatoes is said to keep the beetles away.
- The most effective organic approach for larger fields would be to spray with a solution that contains the bacteria Bacillus Thuringiensis. As the leaves are eaten by the beetle and its larvae, the bacteria then colonizes in their intestines and produces certain toxins that are lethal to them.