Kansas State University


Extension Entomology

Month: May 2015

Alfalfa Update

Wet weather has kept equipment out of the fields and has allowed the insects to flourish.  Fortunately, the plants are also doing well and tolerating these healthy populations of pests.  When these fields dry out and are able to be swathed, there will probably be relatively significant populations of alfalfa weevil larvae and adults still present.  They are accumulated into the windrows at cutting; they will feed on the stems under the windrows until the hay is picked up.  This causes the characteristic stripping in the fields where the regrowth under the windrows is chewed off while the areas beside the windrows grow back.  Once the hay is removed, the adult weevils will exit the fields and no longer be a problem.  Weevil larvae in north central Kansas on 7 May were 93% 3rd instar, and 7% 1st or 2nd instar.  There are many pupae and adults also.



There are significant populations of aphids, mainly pea, in these central Kanas alfalfa fields as well.  Swathing will remove this problem, but there are many beneficial insects helping to regulate these aphids, and hopefully they will stay around after swathing to help manage any other aphids and/or potato leafhoppers that may show up (no leafhoppers detected yet).

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Some small grasshoppers were also noted.  Usually, grasshoppers do better in drier conditions, but not always.  So be aware that grasshoppers are present now and eggs will continue to hatch for the next month.


—Dr. Jeff Whitworth and Dr. Holly Schwarting

New Handy Bt Trait Table available!

Want to know which Bt trait is which? What pest they control? Is it herbicide tolerant? What refuge needs to planted?

The Handy Bt Trait Table from MSU has all these answer in a handy, easy to use table! This is a great resource for agents, consultants, farmers, seed dealers and anyone else who needs to know more about Bt corn traits.

Get your handy copy here: http://corn.agronomy.wisc.edu/Management/pdfs/Handy_Bt_Trait_Table.pdf

handy Bt trait table

Wheat – Aphids

—by Dr. Jeff Whitworth – Dr. Holly Schwarting – J.R. Ewing and Salehe Abbar & Dr. Brian McCornack

Wheat aphids, primarily greenbugs, but bird cherry oat and English grain aphids as well, continue to migrate into wheat fields all over the state. However, there are increasing numbers of lady beetles and parasitic wasps (see photo of mummy). Hopefully these beneficials will keep these aphids well below treatment thresholds.

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More information about greenbug identification,  current management recommendations, or their natural enemies can be found on the myFields.info website (www.myfields.info).


Alfalfa – Weevils and Aphids

—Dr. Jeff Whitworth – Dr. Holly Schwarting – J.R. Ewing and Salehe Abbar

Alfalfa weevil feeding is winding down in north central Kansas, but not as fast as usual. If treatment is still considered prior to swathing do not forget to read the label and follow the PHI (post-harvest interval) required by the product you choose. The untreated control plots in our insecticide efficacy trials are still above our treatment threshold of 1 larva/2 stems, or 50% infestation, and contain many small larvae. Remember, larvae were 1st detected on 13 March so they have been actively feeding for six weeks. However, the good news is many insecticides are still providing excellent protection from one application three weeks ago. See below:

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Aphids continue to increase in alfalfa fields. They are primarily pea aphids with a few spotted aphids. Have not seen or heard of any at, or even close to, treatment thresholds, but populations are increasing. Lady beetle and parasitic wasp populations seem to be rebounding which should help slow down these aphid populations.



—Dr. Jeff Whitworth – Dr. Holly Schwarting – J.R. Ewing and Salehe Abbar

We have received several calls from south central and north central Kansas about termite and ant swarming (see photo). We have probably had more calls so far this year than in the last two years combined. Not sure what that means, but apparently this year the weather has been more conducive to swarming behavior, or possibly last year’s weather was more conducive to population increase, than the previous couple of years. Ants are generally antagonistic towards termites. However, while termite and ant colonies are located a distance apart, the swarmers (adult, winged reproductives) may occasionally end up together at a window or on a sunny wall, etc. Therefore, it can sometimes be a little difficult for the homeowner to distinguish ant swarmers from termite swarmers (see photo). But, it is imperative to make proper identification to ensure proper treatment is performed as treating for ants is much different (and less expensive) than treating for termites! For more information on termite identification, biology and control please visit: http://www.ksre.ksu.edu/bookstore/pubs/MF722.pdf

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Easy Math: 2015 minus 1998 = 17

—Dr. Robert Bauernfeind

Algebra? Trigonometry? Calculus? Not my strongest subject matter. Never was — never will be! But simple math, I can handle. The answer of “17” can only mean one thing to an entomologist: 17-year periodical cicadas. By the end of May and into June, the “buzz” created by massive numbers of newly emerged periodicals will create quite a “buzz” mainly amongst citizens of eastern Kansas.

With their distinctive appearance (black body, blood-red beady eyes and orange-veined clear/transparent wings), there can be no mistaking periodical cicadas for any other insect. In actuality, the simple above-mentioned descriptors are (for lay people) not utilized in taxonomic keys used by systematists to identify/classify cicadas.

Whereas there is a tendency to lump/consider periodical cicadas as “one”, there actually are 3 separate species of 17- year periodical cicadas. Only Magicicada cassinii and M. septendecim have been officially documented as occurring in Kansas. If one wished to differentiate which is which, the body of the smaller cassinii measures .8-inch long with an abdominal width of ¼-inch, whereas the more robust septendecim measures 1.1-inches in length with an abdominal width of 1/3 – inch (quite evident if comparing specimens side-by-side). If not wanting to take measurements, simply flip the specimens over and examine the bottom of their abdomens: cassinii is entirely black whereas septendecim is orangish. Although discernable but a little more difficult to observe is the area between the eye and base of the forewing: black for cassinii and orangish for septendecim. All this being said, by far, cassinii are more common and likely to be encountered than septendecim. Of the 4,437 periodicals that I collected from 37 counties in 1998, 98.7% were cassinii.

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Without seeing an actual specimen, one can discern whether cassinii or septendecim are present. That is, the call produced by cassinii is a continuous somewhat high-pitched buzzing possibly with come ticks interspersed, while the call of septendecim is a more hollow “weeeee whoa weeeee whoa ………..” (sometimes people say it sounds like “pharaoh ……”. Only males are capable of calling/chorusing —- the purpose being to attract females for mating purposes.

Probably the main complaints lodged by people against periodical cicadas have to do with the appearance of emergence holes in the ground (A), occasionally mud turrets produced by nymphs prior to their emergence (B), large number of nymphal exuvia (“skins”) from which adult cicadas emerged (C), and the noise created by the clusters of congregated males (D).

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Also, the egglaying activities can kill tips of branches thus causing the appearance of dead branch tips, which is but an aesthetically brief and inconsequential event.

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The following color-coded map details the documented distribution of periodical cicadas in Kansas. I would appreciate receiving any reports of periodical cicada activities that you encounter —— Phone: 785-539-7510; e-mail: rbauernf@ksu.edu. Of special interest to me would be reports from Morris, Republic, McPherson and Harvey counties. I would visit those counties/sites for the purpose of collecting specimens for incorporation into our Departmental MEPAR holdings. I plan on visiting specific sites in Reno and Stafford counties (where periodicals were reported in 1998) for collection purposes. And I would especially appreciate reports from “uncolored/blank counties” for the purpose of possibly determining the western range of periodical cicadas in Kansas.

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All this being said, the 2015 emergence of Brood IV periodical cicadas (which includes portions of Iowa, Nebraska, Missouri and Oklahoma) was initiated in 1998 when 1st instar nymphs hatched, dropped to the ground and burrowed in. During the past 16 years, they fed by inserting their piercing sucking mouthparts into the xylem tissues of tree and woody shrub hosts. The now fully-developed 5th instar nymphs currently are waiting for soil temperatures to reach the proper temperature (cited to be 64oF) which signals them that the time has come that they should emerge from their underground habitat. After emerging (A), the skin down its back will split, and a “new adult” will emerge (B). Initially it will be white and soft (C). Over the next several hours, it will darken and take on its characteristic coloration (D). However, the exoskeleton will still be soft. An additional 4-5 days will be required for the exoskeleton to harden. It is at this point that cicadas will take flight, males will call, females will respond and mating will occur.

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The female then will use her serrated ovipositor to slice into and create cavities in twigs into which she will insert up to 20 eggs. She will repeat this activity as many times as is required for her to deposit her full complement of eggs which may total up to 600. Six to 10 weeks later (a time at which all of the periodical cicadas will have died), the newly hatched nymphs drop to the soil burrow into the ground, feed for 16 years and reappear/emerge in 2032!