Kansas State University


Extension Entomology

Month: June 2015

Nuisance Moths = “Miller Moths” = Army cutworm Moths

–by Dr. Bob Bauernfeind

Recent questions have been received inquiring about the annoying “miller moths”.  Also, numbers of moth captures in my (at home) blacklight trap have picked up

What are they?  Why so many?  What can I do about them?


“Miller moth” is an all-inclusive umbrella term used to describe any plain brown drab moth.  Because virtually all moth species have wings covered with scales, those scales are fluffed off like dust-in-the-air (as dust associated with flour milling plants).  At this time of year, the “miller moths” of note are army cutworm moths, Euxoa auxillaris.

Upon close examination, army cutworm moths definitely are not plain, brown or drab.  There are 5 morphological forms (called varieties) of army cutworm moths.  Each possesses its own intricate and distinctive wing pattern.  Adding more to the visual array, brown forms of each variety are males, whereas grayish individuals are females.


The seasonal life history begins in the fall of the year when moths deposit eggs in the soil in fields of fall-seeded wheat, alfalfa stands and weedy fields/patches.  Eggs may hatch within several days of being deposited, but may be delayed under unfavorable/dry conditions.  Larvae preferably feed during the dark of night, and seek shelter in the soil during daytime hours.  Army cutworms overwinter as partially grown larvae (red rectangle).


Each year in the central plains states, overwintered army cutworm larvae resume their feeding as temperatures moderate/become warmer.  They complete their development towards the beginning of May, after which they burrow into the ground where they create protective earthen cocoons inside of which they pupate.


Moth emergence usually begins by late May.  Although moths are the mature form of the army cutworm, at this point in time, they are not sexually mature.  For a period of time, moths remain near areas where they emerged.  Then an undefined stimulus (likely photoperiod driven) signals moths across the central plains states to migrate westward to the higher elevations in the Rockies. There in the cool-of-summer, they feed, accumulate body fat and attain sexual maturity.  In mid- to late September, they migrate back to the central plains where they deposit eggs (as previously described) to initiate the next generation of army cutworms.

The current complaints revolve around the moths.  Again, because moths are active during evening hours, they shun daylight.  That is, with the approach of daylight, army cutworm moths seek shelter/cover in any conceivable space.  Excluding moths is difficult because they will exploit very small openings.  Because garage doors seldom are tight fitting, when one opens the garage door, a flurry of moths may rush out.   A car window left open overnight provides an attractive entry point – and when one gets ready to drive to work, he/she will be greeted by a flurry of excited moths.  Open a polycart to deposit a trash bag and you may be greeted by a rush of moths.  Take an early morning walk and as you pass a line of shrubs, you may be startled by hundreds of excited moths darting out.  And so on.  In homes, catch or swat a moth on your wall or curtains/sheers and you will find a coating of “dust” (wing scales) left behind.

An example of the “dust” produced by army cutworm moths can be seen where moths gathered from a single blacklight trap are dumped out of a garbage can.  Talk about being up-to-your-neck in army cutworm moths!


Another interesting tidbit about army cutworm moths:  food for grizzly bears. During summer months, bears move to the higher elevations to feast on army cutworm moths.  It was determined that single moth possesses ½ calorie of fat content.  It was further estimated that a bear obtains 20,000 calories of fat on a daily basis by consuming 40,000 moths per day.


When the Dam Breaks, All Heck Breaks Loose – Periodical Cicadas

–by Dr. Bob Bauernfeind

Probably the most famous flood resulting from a broken dam is the Johnstown Flood.  Doubtful that such could ever happen again given that “oldtime” dams were not constructed like modern day dams, and communities would not be put in potential paths-of-danger.  I don’t know all of the details, but extensive rains added to the waters behind the dam building to the point that the dam could no longer hold back the waters.  The dam burst and the deluge of water swept down and flooded the town (Johnstown, PA) downstream.

So again, stretching-the-rubberband-thin (as I often do):  periodical cicadas.  Eleven days ago (as I now write this), I observed and collected my first periodical cicadas — one here, one there, and so on.  Pretty quiet.  Four days later, I drove a gravel road with windows down —- listening listening listening.  In fact I would stop (to eliminate wheel noise) to listen.  And even shut the motor off to listen.  I would pick up cicadas calling from certain groves.

Three days later, the dam had burst.  That is, with windows down and driving 60+ mph, the wind blowing in my ears and the hum of the tires on-the-pavement road were not enough to drown out the LOUDNESS of periodicals from both sides of the road.  Also, more and more people have become aware of and reported periodicals now that (probably) the greatest percentage of their emergence has occurred.  While I have taken images of what I thought were impressive numbers of periodicals, nothing compares to those which I received from Ron Embry/Sarah Jaster at the Webster Conference Center, Salina, KS.   This brought to my mind an acronym that I use on occasion: TMTC = Too Many To Count!  While not useful for inserting into any formula for purposes of scientific statistical analyses, it serves to satisfy me in terms of relating uncountable numbers.  You be the judge.



Corn Pest Update

–by Dr. Jeff Whitworth and Dr. Holly Schwarting

Checking corn fields between rains indicates some insect activity.  The most visible seems to be corn earworm larvae.  The fields we checked in north central Kansas were in the 8-9 leaf stage and the corn earworm larvae had probably been feeding for about a week.  However, the feeding is only noticed after the leaves unfurl as the larvae are hidden inside the furled leaves.


CEW larva

Checking corn fields between rains indicates some insect activity.  The most visible seems to be corn earworm larvae.  The fields we checked in north central Kansas were in the 8-9 leaf stage and the corn earworm larvae had probably been feeding for about a week.  However, the feeding is only noticed after the leaves unfurl as the larvae are hidden inside the furled leaves.

Ragged leaves corn

We also found western corn rootworm (WCRW) larvae feeding on corn roots.  This field was sampled last weekend but no larvae were detected.  However, in this same field, the larvae hatched and have fed on the roots as seen in the picture.  Just in the last 3-4 days, larval feeding has caused some root damage.

CRW larva and damage

CRW larva

Periodical Cicadas Out in Full Force

–Dr. Robert Bauernfeind

The past two weeks have been filled with reports regarding the wide spread occurrence of 17-year periodical cicadas (refer back to Issues #4 and #7 of the 2015 Kansas Insect Newsletter for basic background information on periodical cicadas).  I am appreciative of those individuals who responded to my request for information/reports/observations of periodical activities in their respective counties, and super-appreciative for specimens submitted to me as well as photographic images.  For the remainder of my inclusions in this week’s Issue #8 of the KIN, I am including several images of periodical cicadas.







An old friend revisited – Wooly maple/briar aphids (WMBA)

–Dr. Robert Bauernfeind

An old friend revisited – Wooly maple/briar aphids (WMBA)

It has been a number of years since I have had occasion to address wooly briar/maple aphids.  And matching dates of past encounters, the timing is right on (in 2007, June 1, and in 2009, May 29).


The inclusion of two very different host plants might have a person asking, “Well, are they on maple or are they on briar?”  In fact, both a primary woody host (maple) and an unrelated secondary/alternate herbaceous host (brier) are required for these aphids to complete their seasonal life cycle.


Despite their rather simple and familiar appearance, some aphid species (such as wooly maple/brier aphids) have very unusual and complex reproductive adaptations.   While most people are aware that the aphids which they encounter in their gardens and landscape plantings are all females which (in the absence of males) reproduce parthogenically by giving birth to living offspring, sexual forms are required for mating purposes and the eventual production of overwintering eggs.  This is where maple trees come in —  where (in the Fall) WMBA deposit overwintering eggs.


Thus, beginning in Spring, each 1st generation aphid emerging from an overwintered egg is a wingless female called a fundatrix (foundress-of-a-colony).  The offspring of each succeeding generation (all females, called fundatriginae) also produce living young.  These aphids eventually become overcrowded as they colonize twigs and branches.



While the above-pictured aphids appear to be “normal aphids”, they aren’t called wooly aphids for no reason.  That is, these aphids possess specialized wax-producing glands.  And at some point, they will begin producing white flocculent strands which provides them with their “wooly appearance”.


While not being sure of the exact stimulus at work, at some point, possibly overcrowding and constant touching/bumping-into-each-other “triggers” an internal response mechanism promoting wing production in developing aphids.  By mid- to late June, those aphids (again, all females which are now called exules) emigrate from their woody maple host to their alternate herbaceous host which, in Kansas, would likely be the plentifully-abundant greenbrier.

Upon reaching the summer host, exules deposit their offspring (you guessed it, all wingless females) which in turn account for additional summer generations on their briar hosts.  Upon entering Fall, shortened daylight hours hourst, decreased temperatures or a combination of both set off another change in aphid forms (now called sexuparae) of which there are two types:  Gynoparae are winged females which emigrate back to the primary host where they produce wingless females called oviparae;  and androparae are winged females which emigrate back to the primary host where they produce wingless males.  Males mate with oviparous females which then deposit the aforementioned fertilized overwintering eggs.

Now to the discussion on wooly maple/briar aphids that most readers care about.  Are they harmful?  Is there a need to control them?

The only real complaint leveled against wooly maple/briar aphids revolves around the “sticky mess” which they are responsible for.  WMBA congregate on the twigs and branches of the different varieties of sugar maples.  They insert their piercing-sucking mouthparts into the phloem elements which conduct the flow of plant juices/sap.  Fairly stationary, aphids continually withdraw the sugar-rich sap.  The excess juices are eliminated/excreted in the form of “honeydew”.  The honeydew “rain” will coat anything beneath WMBA-infested  trees  — vehicles, sidewalks, driveways, house decks, picnic/patio furniture, children’s swing sets and toys, items on clothes lines, and so on.  Being sticky and nutrient-rich, captured airborne fungal spores can proliferate into unsightly accumulations of dark-colored sooty mold.  But other than that, trees easily withstand wooly maple/briar aphid infestations as seen below.


While insecticidal sprays and/or the use of forceful water sprays might seem called for, neither is practical in practice.  And, unnecessary!  By the time such infestations are discovered, within a very short period of time (2 weeks, possibly less), as described in the prior explanation of their seasonal developmental cycle, they will quickly dissipate on their own when they seek out their alternate summer host.  IT IS HIGHLY UNLIKELY THAT THEY WILL FIND THEIR WAY BACK TO THE SAME TREE HOST FROM WHICH THEY IMMIGRATED —- at least by my experiences/inspections.

Maybe one last-and-legitimate gripe:  handle with care.  They do leave a hard-to-remove stain that might relegate good clothing to a wear-only-at-home status.



Corn and Wheat Pest Update

–Dr. Jeff Whitworth and Dr. Holly Schwarting


Plants in north central and south central parts of the state are finally starting to grow.  All the cloudy, wet conditions have not been the best for corn development and many fields are a little more chlorotic looking than usual for this time of year.  This stalled development usually allows pests more time to feed and thus cause damage.  Seed treatments only provide protection for 3 to 4 weeks (check label) from planting, so most of that protection has dissipated.  However, we have not seen nor heard about much pest activity yet.  A few thin stands have been noted which can be caused by many different pests, probably most common so far has been wireworms.  Generally, however, most fields are past seedling damage.

wireworm 1

wireworm 2

We have received a few calls about armyworm activity in wheat and sorghum, so when these larvae pupate and then emerge as adults to lay eggs, most corn will be in the whorl stage so there may be some whorl-stage leaf feeding which is always highly visible but causes very little actual impact on yield.


We have not seen any “worms” in wheat, but have received several calls about armyworms feeding on leaf tissue.  Armyworms should move to another grass host, i.e. corn, sorghum, brome, etc. as the wheat begins to senesce.  They actually devour leaf tissue and thus are not actually feeding on the grain.


If there are thin, light green or tan worms feeding on the wheat head they are probably wheat head armyworms (see photo).  They can and will actually feed on the grain whereas the armyworm feeds on the foliage around the grain – not the grain itself.

wheat head armyworm

If you decide to treat either pest, please refer to the Wheat Insect Management Guide, 2015: http://www.ksre.ksu.edu/bookstore/pubs/MF745.pdf and make sure to check the label for the preharvest interval (PHI) if spraying wheat this close to harvest.

Rose Sawflies

–by Raymond Cloyd

There are at least two species of sawflies that attack roses during this time of year; the rose slug (Endelomyia aethiops) and bristly rose slug (Cladius difformis). Rose slugs are the immature (larval) stage of sawflies, which are black to yellow-colored wasps.

Rose sawfly females make pockets or slits along the edges of rose leaves using their saw-like ovipositor (egg-laying devise), and insert individual eggs. Eggs hatch into larvae that look-like a slug. Larvae are 1.2 cm in length when fully grown and yellow-green in color, with an orange head (Figure 1). The larvae eventually fall on the soil surface to


pupate. Rose slugs overwinter as pupae in earthen cells created by the larvae. There is usually one generation per year in Kansas. Bristly rose slug larvae are pale-green in color and 1.5 to nearly 2.0 cm long. The body is covered with numerous bristle-like hairs (Figure 2). There is generally one generation per year in Kansas.



Rose slug larvae feed on the underside of the leaf resulting in the leaves having a skeletonized appearance (Figure 3), eventually they create notches or holes on the leaf margins. Bristly rose slug larvae feed on the leaf undersides and also cause leaves to appear skeletonized (Figure 4). However, the larvae may chew larger holes than the rose slug.


Small infestations of either the rose sawfly or bristly rose slug can be removed by hand and subsequently placed into a container of soapy water. A forceful water spray will quickly dislodge sawfly larvae from rose plants; consequently, sawfly larvae are not able to crawl back onto rose plants. A number of contact insecticides (various active ingredients) may be effective in suppressing populations of both sawflies. However, the bacterium, Bacillus thuringiensis subsp. kurstaki (sold as Dipel or Thuricide) will have no activity on sawflies as this compound only works on caterpillars.