Insect Diagnostic Laboratory

Soldier Beetle

 

Soldier beetles are elongate-narrow, soft-bodied and about ½ to ¾ inch in length.  One very common species is orangish-tan with darker color at the wing tips. They are nicknamed leatherwings because of their soft, flexible "leathery" texture wing covers.  Soldier beetles resemble lightningbugs but do not have light-producing organs.

Soldier beetle adults and larvae are predacious and feed on other insects.  They are beneficial and harmless.  It is unnecessary to control them. 

 

We have had numerous calls and messages all this month about boxelder bug nymphs.  Boxelder bugs have a simple life cycle of three stages: egg, nymph and adult.  The adults are well-known; the nymphs look very similar but are smaller and bright red because they don't yet have the black wings to cover their abdomen.  The picture above is of an older nymph with the black wing buds showing.  Younger and smaller nymphs are more red with little if any discernable black markings where the wings will someday be.

These bright red, soft insects are very abundant and present in unlikely places, and not just on trees like we expect.

It is not essential to control boxelder bug nymphs this early in the summer.  These are not the same bugs that will invade the house in the fall.  The nymphs present in June will mature into adults that will reproduce in July.  It is this second generation of the summer that produces the accidental invader adults in October.  The number that will be present in October is dependant on the upcoming weather, and killing some nymphs now will not make as much difference as will the weather in July.

Small dead flies on shrubs, vines, flowers and vegetable plants is a common sight in some springs.  The small gray flies resemble small house flies (slightly less than ¼ inch long).  They may be noticed everywhere and anywhere, but always dead.

These small flies are the adult stage of a moderately important pest called the seedcorn maggot.  As the name implies, the larvae (or maggots) attack and damage seed corn (and seeds of other crops such as soybeans, vegetables, etc.) planted in  damp, high organic matter soil.  Populations are highest in cool springs when seeds are slow to germinate.

The adult flies are harmless.  They cannot bite, sting or carry diseases.  They cannot feed on plants.  No control is necessary.

Part of the reason seedcorn maggot flies attract attention is their method of death.  A large portion of the flies dies as a result of a fungus that invades their bodies.  Many of the infected flies die after landing and attaching to the foliage of ornamental plants.  The dead flies, stuck to the plants, are obvious to homeowners and landscapers inspecting plants for signs of trouble and they are improperly blamed for any and all symptoms on the plants.  However, the flies did not feed on the plants or cause any of the holes, spots or discolorations that may be present.  To repeat, no treatment is warranted.  They are dead, for gosh sakes!

Seedcorn Maggot Fly

This week we got an interesting sample of brown maggots.  Our fly expert, Dr Ken Holscher, was able to correctly identify them as maggots of the soldier fly.  Soldier fly maggots occur in decaying organic matter.  They are often found in manure or garbage.  When found indoors they may be coming from garbage, a broken septic tank, or possibly a bee nest in the wall.  Soldier flies are harmless, and the best control is to locate and eliminate the organic matter they are breeding in. 

 

As you drive in the country during the fall, you are probably noticing many caterpillars crossing the road.  These are woolly bear caterpillars and there are 8 or more species in the U.S.  The best-known woolly bear is called the banded woolly bear. It is black at both ends and reddish-brown in the middle. The adult is called the Isabella moth.  The second generation is the one noticed in late fall when the woolly bears are crossing the roads, usually in great haste as if they have someplace special to go. In fact they are only scurrying to find a sheltered location under dead plant debris, etc. where they will spend the winter as a larva. In the spring they will feed briefly before changing into a cocoon and eventually a moth.  Eggs laid by the female moths start the cycle over again.

The banded woolly bear is the species mentioned in winter-prediction folklore that claims longer the black at the ends of the body, the more severe will be the coming winter. As you might expect, science has debunked this legend by showing the amount of black varies with the age of the caterpillar and the moisture levels in the area where it developed.

Banded woolly bear caterpillar.

The past couple of weeks many Iowans have been encountering the one of my favorite ants, the larger yellow ant.  In the late summer and fall mixed colonies of winged swarmers and wingless worker ants move toward buildings and try to enter through cracks or gaps in the foundation.  During the summer the workers feed almost exclusively on honeydew gathered from aphids or mealybugs and they are active at night.  In the winter the ants commonly gather near foundations and enter houses to spend the winter.  The temporary indoor, winter nest is usually somewhere in the basement under a loose brick or board or in a crack in the wall or floor. The ants do not forage for food through the house and apparently cause very little damage except to create piles of dirt at the entrance to the nest. Reportedly, these ants try to return to the outdoors sometime in the early spring if left undisturbed.  Control of larger yellow ants is not critical, since they cause little damage other than the annoyance of their presence.

 

During the late summer, small, black and white insect known as the minute pirate bug makes its presence known in a very convincing manner by biting with an impact that is out of proportion with its size.

Minute pirate bugs are present all summer in fields, woodlands, gardens and landscapes where the feed on small insects and insect eggs.. They quietly go about their business without anyone taking notice until late in the summer when they migrate from fields and woodlands and begin the disagreeable behavior of biting humans. Their bite is surprisingly painful for such a small insect as they probe their short blunt beak into the skin. They do not feed on blood or inject a venom or saliva.  People differ in their response to pirate bug bites. Bites on some swell up like a mosquito bite, some turn red and for others there is no reaction at all.

Wearing dark clothing on very warm days when pirate bugs are abundant may help reduce your attractiveness to the bugs. Repellents are generally not effective though you may want to try them to see for yourself if they work or not for you.