Ladybugs, Lady Beetles

   They are red, orange or shades in between and tend to invade homes in late fall.

   Ladybugs and lady beetles are different names for the same bug that some people see as a pest, but I see as a benefit. I don’t have the large-scale home invasion that some people do, so that could be why I see ladybugs through rose-colored glasses. When they do come indoors, I have a spot for them on my houseplants.

   My houseplants spend the summer outdoors and are given a good shower before I bring them inside in the fall. I don’t use any type of chemical insecticide, and that’s where the ladybugs come in: put them on the plants and they spend their days looking for tiny bugs to eat. They’re amazing to watch in action.

 I know my solution isn’t for everyone, so following are tips from Iowa State University about indoor control and other helpful information:

Ladybug in action

Ladybug in action

 

  The Asian lady beetle is present all summer but is most noticeable in the fall when second generation adults migrate from trees, gardens and fields to reflective, vertical surfaces (such as the south side of the house) in preparation for winter hibernation. 

 

   Asian lady beetles are a beneficial biological control in trees during the summer, and in fields and gardens during the fall, but can be a severe household nuisance during late fall and winter. Wooded residential and industrial areas are especially prone to problems.

   The origins of the Asian lady beetles are not clear, although it appears the current pest species was not purposefully released in the United States or in Iowa. Beetles that arrived by accident in ports such as New Orleans in the late 1980s have crawled and flown all by themselves to all corners of the country.

   The multicolored Asian lady beetle is 1/3 inch in length; dome-shaped; yellowish-orange to red with variable black spots on the back. Deep orange is the most common color. The 19 black spots may be faint or missing. There is a black “W” shaped mark on the thorax.

   Asian lady beetles, like other accidental invaders, are “outdoor” insects that create a nuisance by wandering indoors during a limited portion of their life cycle. They do not feed or reproduce indoors; they cannot attack the house structure, furniture, or fabrics. They cannot sting or carry diseases. Lady beetles do not feed on people though they infrequently pinch exposed skin. Lady beetles may leave a slimy smear and they have a distinct odor when squashed.

   Asian lady beetles follow their instinctive behavior and fly to sunny, exposed surfaces when preparing to hibernate through the winter. The time of beetle flight varies but is usually from mid-September through October (depending on weather.) Light colored buildings and walls in full sun appear to attract the most beetles.

   Sealing exterior gaps and cracks around windows, doors, eaves, roofs, siding and other points of access before the beetles appear can prevent unwanted entry. Experience suggests, however, that comprehensive pest proofing is time-consuming, often impractical and usually not 100% effective.  For large infestations with intolerable numbers of beetles, spraying pyrethroid insecticides such as permethrin or esfenvalerate to the outside of buildings when the beetles appear may help prevent pest entry. Homeowner insecticides other than pyrethroids usually do not provide satisfactory prevention.

   Long-term relief may come from planting trees that will grow up to shade the south and west sides of the house. The most practical control for beetles already inside is to vacuum or sweep them up and discard. Indoor sprays are of very limited benefit. Interior light traps are available.

Donald Lewis, of Iowa State University’s Department of Entomology, adds the following about ladybug myths and facts:   

Myth: Ladybugs are different from lady beetles

Fact: Ladybugs and lady beetles and ladybird beetles are all different names for the same thing.

Myth: Asian lady beetles come from soybean fields.

Fact: There are Asian lady beetles in soybean fields, but also many other places including trees and, gardens.

Myth: Soybean harvest causes multicolored Asian lady beetles to migrate to town and to houses.

Fact: Day length and temperatures trigger migration – expect swarms of beetles on first warm days after frost. Soybean plants lose their leaves, and therefore any aphids the lady beetles might be eating long before harvest. The beetles leave soybean fields as the plant leaves begin to turn yellow and not when the combines arrive.

Myth: Farmers released the lady beetles to eat the soybean aphid

Fact: No releases were ever made in Iowa. Multicolored Asian lady beetles arrived in Iowa by wandering from adjoining states several years before the soybean aphid appeared.

Myth: Lady beetles breed in the walls of the house during the winter.

Fact: They do not reproduce during the winter.

Myth: Finding a ladybug brings good luck.

Fact: This myth might not be all wrong. Since ladybugs eat aphids, other small insects, mites and the eggs of insects and mites, you could argue that ladybugs do bring good luck to farmers and gardeners. However, there is no evidence to prove that the good luck extends beyond the benefit of fewer aphids feeding on your plants.

Myth: You can tell the age of a ladybug by counting its spots.

Fact: There are over 5000 different species of lady beetles (ladybugs) in the world and approximately 475 species in North America. There may be as many as 100 different kinds in Iowa. The numbers and arrangements of spots on the backs of ladybugs are distinctive for the different species, and once a lady beetle emerges as an adult it never changes its spots.

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