Is That a Good Ladybug or a Bad Ladybug?
by Kate McIntyre
Old House Web Columnist
The ladybug is many people's favorite insect for a couple of reasons. For one, ladybugs are beneficial. They eat insects that chew up your garden, such as aphids. And they are much cuter than other good guys of the garden, such as spiders and daddy long legs. However, not all ladybugs actually help your garden. Some will snack on your flowers and vegetables just as voraciously as the aphids.
Ladybugs species can look very different from one another. Ladybugs can be pink, red, orange, or yellow, with anywhere from 16 black spots to no spots at all. Some ladybugs are nearly entirely black. There are over 6,000 species of ladybugs worldwide, so it would be quite a task to learn about them all. It is much easier to focus on the ladybug species that are not beneficial.
There are two species of ladybugs, the Mexican bean beetle and the squash lady beetle that are not carnivorous. Instead of eating garden pests, they eat your garden. Luckily, they look similar to each other and unlike most other species of ladybugs. The Mexican bean beetle has a yellowish body covered with 16 black spots. As its name suggests, it feeds on the leaves of most varieties of bean plants. The other imposter to keep an eye out for is the squash lady beetle. The squash lady beetle is also yellow, but it has 14 black spots rather than 16. Its favorite foods are the leaves of squash, cucumber, and watermelon plants.
If you have doubts about whether a beetle in your garden is a good ladybug or a bad one, take a close look at its surroundings. Do you see any aphids on the plants? If so, this is a good indication that you have found a good ladybug. If, on the other hand, you see no other insect pests and there is considerable damage to plants' leaves, you have probably found a villain.
About the Author
Kate McIntyre is a writer in Portland, Oregon. She holds a B.A. from Harvard University and an M.F.A. in fiction writing from Oregon State University.