Articles by Jim Gainan

As published in the Billings Gazette

Ladybugs: An Eco-Friendly Alternative to Insecticides

Ladybugs: a eco-friendly alternative to insecticides
June 30, 2013 12:00 am

Every spring, the counters at our Garden Center are literally crawling with ladybugs.  Hold on; they’re not running around loose, but are contained in bags!  Do people really buy ladybugs?  Yes, because ladybugs are a natural control for aphids and other soft-bodied insects that may be munching on the plants in your yard!

Ladybug larvae look like little black spiny alligators with bright spots.  They may look intimidating, but they will not harm plants or people.  However, those aphids better watch out!  A single ladybug larva will eat dozens of aphids a day, up to 400 during its development and an additional 300 aphids as an adult.  In its entire lifetime, an adult ladybug will consume approximately 5000 aphids.  Aphids may be a ladybug’s favorite menu item, but it will also feast on mealybugs, spidermites, scale and some eggs of other insects.

Adult ladybugs have round-to-oval shaped bodies that can range in color from yellow, pink, orange and red.  Some species have spots, while others do not.  When disturbed, adult ladybugs secrete a chemical from their joints that smells and tastes terrible, discouraging predators from eating them.  Their bright color helps predators remember the distasteful encounter and serves as a future warning.

Female ladybugs are a little larger than the males and will search out a colony of aphids and lay her egg clusters among them.  She will lay 10-50 light yellow eggs in each cluster and will lay up to 300 eggs in her lifetime.  The eggs hatch in 2-5 days and the larva will feed for 2-3 weeks before they pupate.  The adult emerges in about a week.  Ladybugs can produce five to six generations in a single season.  This reproductive capacity paired with their ravenous appetites enables the ladybugs to rapidly clean out their prey, making them a very beneficial insect for us.

In the fall, the adults will gather in a protected area to hibernate, perhaps at the base of a tree, along a fence, on the sunny side of a house or even under rocks -- anywhere they are protected from the winter cold.  These colonies are called aggregations.

Many of the ladybugs sold for natural pest control are collected in the mountains of California where they congregate in huge colonies in the same site each year.  Some colonies have been known to have as many as 500 gallons of ladybugs.  Each gallon contains 72,000-80,000 adults.

If you buy a bag of ladybugs for your yard, water down the area in which you will be releasing them.  This will encourage them to stay.  Release them in the evening; ladybugs don’t travel much at night.  If prey is plentiful, they will stay.  However, if there is not a food source, they will fly to other areas.  Finally, before grabbing an insecticide, just remember that you may have friendly bugs helping you out in your garden.