Marigold for attracting beneficial insects

(Question)

Hello, I am wondering if there is one particular marigold that is a more potent pest deterrent than others. Thanks

(Answer)

An interesting question! For many years, people have planted marigolds in their gardens with the notion that they repel harmful insects. In fact, there is no real evidence that they do so. They may, however, attract some beneficial insects and those insects will work for you. For example, ladybugs will eat aphids, as will lacewings; parasitic wasps will attack aphids, caterpillars, beetles, scale, and flies. There is also evidence that marigolds have a detrimental impact on damaging nematodes (microscopic worms) that attack root vegetables.

However, marigolds may also attract spider mites, which, in turn, might move to your tomato plants.

Here are two interesting university articles on the subject, from the Universities of Alabama and Arizona, respectively:

http://www.aces.edu/dept/extcomm/specialty/marigolds.html

http://cals.arizona.edu/yavapai/anr/hort/byg/archive/marigoldsandnematodemanagement.html

On the other hand, marigolds and other flowers … especially edible ones … are attractive additions to your vegetable garden, so feel free to plant them with beauty as the primary goal and if there are any bonus benefits, so much the better!