Posts tagged aphids

Good vs. Evil: Asian lady beetles and Japanese beetles

Asian lady beetle

Asian lady beetle - a good bug (photo/Cindy Hadish)

Their names are similar and they’re from the same region of the world, so I can see why some people are still confused about Asian lady beetles and Japanese beetles.  But when it comes down to it, there’s really no comparison. The bug pictured here – the reddish/orange lady beetle, is a beneficial insect. It feeds on aphids and other plant pests and doesn’t destroy anything, though I realize some people resent their intrusion in homes in the fall. On the other hand, the copper-colored Japanese beetle, a recent foreign invader in Iowa, is known to devour at least 300 plants, including hollyhocks, roses, raspberries, linden trees and grapes. If you see your leaves turning to lace, the likely culprit is the Japanese beetle.  Japanese beetles have no known predators here, other than me. So feel free to get rid of as many as you can. As mentioned previously, the most environmentally friendly method is to knock them into a bucket of soapy water when they’re sluggish – early evening seems to be the best time. If you have other suggestions – maybe from our East Coast readers and others who have learned to cope with Japanese beetles – please add your comments below.

Japanese beetles (photo/Cindy Hadish)

Japanese beetles - not a good bug, or just plain evil? (photo/Cindy Hadish)

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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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Know your bugs

 

 
Sixspotted tiger beetle, a beneficial insect
Sixspotted tiger beetle, a beneficial insect

   The watch continues for the notorious emerald ash borer, a pest that has devastated ash trees in at least seven states, including neighboring Illinois.

   The emerald colored bugs appeared near Detroit six years ago and have been advancing toward Iowa.

   Having seen photos of the emerald ash borer, I quickly reacted when I saw a pretty emerald bug outdoors earlier this summer.

   Iowa State University has an awesome insect identification program that allows Iowans to e-mail a photograph of their bug and have it identified by entomologists.

   I shot a photo of my bug next to a ruler to show its size and sent it to the site.

   Good news: it wasn’t an emerald ash borer. Bad news: I had killed a sixspotted tiger beetle, a beneficial insect that extension entomologist Donald Lewis said is easily mistaken for an emerald ash borer.

   Lewis tells me the beetles are predators that chase other insects across the ground in woodlands.  They hunt food like a tiger.

   Tiger beetles are ecologically beneficial.  They are not a pest.  The beetles do not bite, sting or carry disease.  They do not feed on crops, trees or houses.  They are remarkably fast and difficult to catch.

   I’m bummed that I caught one, but glad it wasn’t an ash borer.

Lewis says the emerald ash borer is much smaller and narrower and does not have the long sharp jaws of a tiger beetle (predatory

hunter.)

 

   For Iowans who have a bug they’d like identified,  specimens can be submitted to the Iowa State University Plant and Insect Diagnostic Clinic for diagnosis at no charge.

   You can e-mail a close-up digital image to  insects@iastate.edu

   Specimens can also be sent to the clinic.

   Bugs should be dead when shipped and mailed in a bottle, box or padded envelope.  Soft-bodied insects such as caterpillars, aphids and ants, and spiders, mites and ticks can be preserved in hand sanitizer gel.  Hard insects such as moths, butterflies and beetles do not need to be preserved, but they should be restrained inside the container so they don’t bounce around during shipment (for example, secure a moth or butterfly inside a box with layers of dry paper toweling.)

    Mail sample to:

Plant and Insect Diagnostic Clinic
327 Bessey Hall
Iowa State University
Ames, IA 50011-3140

 

Include information about where you live, where you found your insect, and how to get in touch with you. 

 For  a photo of the emerald ash borer, go to:  http://www.emeraldashborer.info/files/E2944.pdf

 

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