Insect Diagnostic Laboratory

Spring is the time we begin to notice ant mounds on sidewalks and driveways and in the lawn.  Most ants are beneficial to the soil and do not require control.  However, ant mounds may be a nuisance and they can be unsightly, may cause lawn unevenness, and if large, may smoother out the surrounding grass.  The ants are not dangerous.  The ants found in Iowa lawns are not biting or stinging pests.  The fire ants of the southern U.S., well known for their aggressive behavior and painful stings, are not present in Iowa.
 
To avoid some of the worst ant hill activity rake or wash (with a water stream from the garden hose) on a regular and frequent basis anthills that appear above the grass tops.  The need for such maintenance will be greatest during periods of prolific ant nesting activity (such as during periods of wet spring weather).  
 
If warranted, you can spot treat anthills with an insecticide such as carabaryl, permethrin or other insecticide labeled for use in the home lawn.  Read and carefully follow instructions on the insecticide label.  Rake the anthill flat and apply granules, dust or liquid solution onto the soil surface.  If granules or dusts were used, rake the area lightly after application.  Irrigate the mound area to move the insecticide ingredient into the soil and away from the surface where it may be exposed to people, pets or wildlife.  Keep children and pets away from the treated area until the grass has dried. 

The Insect Diagnostic Clinic is staffed by Donald Lewis and Ken Holscher.

The Iowa Insect Diagnostic Clinic is staffed by Donald Lewis and  Ken Holscher.

E-mail:  insects@iastate.edu

Phone number: (515)294-1101

If you have an insect you would like identified you can e-mail a digital image to insects@iastate.edu, take your insect to your local extension office (list of office locations), or send it to us directly.  Please place your insect in a container to prevent crushing in the mail and send it to:

Insect Diagnostic Clinic
Department of Entomology
Insectary Building
Iowa State University
Ames, IA 50011-3140

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

This week the Iowa Insect Diagnostic Clinic has officially declared that the annual multicolored Asian lady beetle migration to homes has begun! The beetles spend their summers in our gardens, forests, and crop fields eating aphids and many other pest insects. In the fall, the shorter days and first frosts trigger their annual search for a good spot to spend the winter. Research has found that these insects tend to fly toward large objects that have a high amount of contrast. Unfortunately, our homes are large objects and with the afternoon light casting many shadows on the southern and western sides of the house, they also have very contrasting patterns. Normally the lady beetles would prefer to overwinter in cracks and crevices of a cliff or other rock face, but since they are lacking in most of Iowa, they tend to locate many of our homes. In general houses are not the best spot for overwintering. The beetles accumulate within the walls of homes where they would ideally stay cold and moist all winter. The cold keeps them dormant so they don't crawl about and use up their food stores, and the moisture keeps them from drying out and dying. Unfortunately for the lady beetles, we heat homes all winter so the beetles often become active and the heat also dries out the air.

Another sure sign of fall - in addition to the woollybears crossing the road - is the appearance of ctenuchid moths on the last blooming flowers of the summer (ctneuchid is pronounced with a silent "cee") . These attractive moths have the unusual habit of flying during the daytime. Their vague resemble to wasps might impart some measure of protection from predators as they sit quietly on flowers for long periods of time. Most of the approximately 2000 species of ctenuchid moths in the United States are tropical species restricted to the southern states.

The Ctenuchids typical to our area have dark brown to almost black smoky wings and a shiny metallic blue-black body. The head and collar region are bright orange, and the wings are fringed with white.

Ctenuchid caterpillars feed on grasses, sedges and other plants. The caterpillars are not pests in our area and neither are the moths. Ctenuchid moths on flowers are another interesting and colorful reminder of nature's diversity.

During the past couple of weeks many homeowners have been surprised to find tiny brown beetles all over their homes. We have dubbed this beetle the "new house beetle" because it is so commonly reported by owners of newly built houses. The beetle is a common fungus beetle known as the foreign grain beetle.

Foreign grain beetles are oblong, reddish-brown and only 3/32 inch long. A distinguishing feature seen with magnification is the presence of tiny knobs or bumps on the front corners of the thorax, the segment right behind the head. The beetles are strong fliers and they are attracted to lights.

Foreign grain beetle adults and larvae feed on molds and fungi, and not on grain as the name would imply. Almost any mold or fungus growth may support their growth, though they are common in damp or spoiled grain.

However, as indicated above, foreign grain beetles are most frequently discovered as an unwanted house-warming guest in newly constructed homes. The beetles come from inside walls where molds are growing because of moisture that was sealed into the walls during construction. This moisture could come from wood left outdoors and exposed to rain before or during building, rain that blew into the house before it was “closed in,” or moisture from drywall compound applied over sheetrock. Beetles emerge from the new house walls for a period of several weeks until the house completely dries out. Problems with this pest are usually self-limiting as the seasons change and as moisture trapped in new houses dries out naturally.

This week the Insect ID Clinic received one of my favorite insects, a northern mole cricket. Mole crickets are one of the less common accidental invaders found inside houses and buildings in Iowa is also one of the most appropriately named insects. These distinctive insects look like miniature versions of the common, lawn burrowing moles with their large, spade-like front legs. As the name implies, mole crickets live under ground in burrows.

Mole crickets are brown and about 1 1/4 inch long. They are covered with fine hair and have a soft, satin appearance. Their short antennae are barely noticeable, but they have two long cerci (stout thread-like appendages) that extend out from under the wings at the tail end. The hind legs of mole crickets are vaguely cricket- or grasshopper-like with only slightly enlarged femurs. The tibias of the front legs however, are greatly enlarged and the first segment of the front tarsi is broad, spade-like and equipped with four prominent, stout teeth.