Ever paused to consider the purchase of one of those little net sacks crawling with ladybugs that they sell at nurseries and garden centers? Ever wondered if they actually do anything useful for your garden?
Well, the answer is: maybe.
Coccinellidae is the formal name of the family of beetles that are commonly called ladybirds or ladybugs. Although most commonly thought of as the cute little insects with red wing covers decorated with black dots, ladybugs can be grey, orange, yellow, brown or black. Over 450 species are native to North America and all are excellent aphid eaters, both in larvae and adult form. Ladybugs are capable of consuming up to 50 to 60 aphids per day, but will also eat a variety of other insects and larvae including scales, mealy bugs, leaf hoppers, mites, and various types of soft-bodied insects. A single ladybug may consume as many as 5,000 aphids in its lifetime.
So who wouldn’t want these cute and helpful creatures populating the garden? The problem is how to entice them to set up residence.
The effectiveness of buying ladybugs from a nursery or over the internet and releasing them into your garden to feed and breed is questionable. Many entomologists have noted that once released, most ladybugs will migrate right out of your garden before settling down to eat and procreate. It is quite likely that your neighbors may benefit more from the ladybugs you purchase than you will.
Another problem associated with purchasing ladybugs is the introduction of very predatory species of ladybugs into areas where they didn’t previously exist, thereby displacing the native coccinellidae. For example, the multicolored Asian Lady ladybug was introduced in the United States to control aphids on agricultural lands, and subsequently became a pest, driving out native species, wintering over in large numbers inside homes and biting the human residents. They have effectively crowded out the locals and taken over.
Another ecological problem involves the procurement of ladybugs for sale. Commercial vendors collect the ladybugs during the winter or early spring, when the beetles have aggregated in large numbers at their overwintering sites. They keep the ladybugs inactive by refrigerating them until it is time for shipping. This harvesting of wild ladybugs may have unintended consequences for their natural habitat.
If, despite the drawbacks, you want to try releasing ladybugs into your garden, here are some simple guidelines to follow:
- Make sure you purchase ladybugs that are native to your area.
- Don’t release ladybugs unless you have plenty of aphids in your garden – they will simply go elsewhere looking for food.
- Release your ladybugs in the evening, when they are less likely to fly away.
- Make sure your garden has plenty of moisture before you release your ladybugs; if it has been dry, give your plants a light misting of water before release.
The alternative to buying ladybugs is attracting the local species to your garden. Ladybugs supplement their insect diet with pollen and nectar from flowers, so if you plant things they like, ladybugs are more likely to come to your garden and stay. Composite flowers like Aster, Cone Flower, Sunflower and Yarrow give ladybugs places to nestle in when not on the hunt. Other species they are fond of include Alyssum, Asclepias, and Penstemon. As for edibles, ladybugs love cilantro, carrots, dill and chives, among other things. So if you plant some of the above, and if you have some aphids around, the ladybugs will come.
Ladybugs are definitely an insect worth having in your garden, but buying ladybugs may not be the most effective or ecologically responsible way to get them there. Creating an inviting habitat is the current method favored over buying ladybugs.