Monday, April 13, 2009

Ladybugs - Should you buy them?

With spring arriving many gardeners are looking to be more “green” or even organic. There are many ways to do this but one area many are interested in is pest management. Unfortunately people’s good efforts are not always so eco-friendly. From the time we are young we are told that ladybugs (ladybird beetles) are good, and they are! They are excellent to have in the garden, but the real question is, “should you buy them and release them?”

Buying ladybugs… is it a good idea?

First thing you should think about is where they are coming from. Almost all “red” ladybugs are harvested from the wild. In the Spring, as the Sacramento and San Joaquin Valleys warm up the ladybugs (Hippodamia convergens) migrate to the Sierra Nevada foothills. There, they congregate in large numbers on the forest floors. Businesses then come along and scoop up the beetles, removing them from their native habitat. They are then taken to coolers for storage until they are to be shipped. So, why is this an issue?

  • It removes ladybugs from their native habitat.

  • Once released most will not stick around, they leave, providing little or no control.

  • A percent of the ladybugs may be parasitized by a small wasp, Dinocampus coccinellae. It develops as an internal parasite of lady beetles and kills them. Research has shown this to be an issue. A study found on average 8% of the ladybugs purchased by researchers carried parasites.*

  • Microsporidia, a disease of ladybugs, was also detected in individuals from 13 of 22* shipments in these studies.

So by releasing infected ladybird beetles you may be spreading these parasites and diseases. It’s much more effective and eco-friendly to attract them in naturally with organically** grown plants like, dill, yarrow, sunflowers, angelica, and other assorted flowering plants. If you want to do a release of beneficial insects, release laboratory reared ones. An excellent option to ladybugs are green lacewings. The larva of green lacewings will do an excellent job of feeding on plant pests such as aphids, mealybug crawlers, scale crawlers and other garden pests. They are commercially available from Beneficial Insectary.

*Natural enemies of the convergent lady beetle, Hippodamia convergens Guérin-Méneville: Their inadvertent importation and potential significance for augmentative biological control. S. Bjørnson Department of Biology, Saint Mary’s University, 923 Robie Street, Halifax, NS, Canada B3H 3C3 Abstract
** Organically grown plants will not have harsh pesticide residue on them that can kill the beneficials. They will also not have systemic pesticides inside of them that can not be washed off.

1 comment:

  1. Good information ! I think this could make people understands overall before purchasing them and providing the attractors from organically grown plants is certainly the answer for these ladybugs rather them buying them.