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Extension Entomology

Category: Field Crops

Field crop pest and beneficial organisms.

Insect Diagnostics 2022 Season Summary

–by Anthony Zukoff – Entomology Southwest Research and Extension Center
Garden City, KS

 

 

Insect diagnostic services are available to members of the public seeking assistance identifying an insect or suspected insect related problems. The Insect Diagnostics ID Request Form can be accessed online and after providing observation information such as location and date of the sighting along with answering a set of questions intended to help with the identification process, one can then upload up to 3 photos and submit the form.  The inquiry is then forwarded on to one of the entomology extension specialists.  Within a few days, usually less than two, the identity of the insect along with appropriate life history information and/or control measures is then sent to the client by email or phone.   The online submission process takes only a few minutes and can be accessed with desktop computers and mobile devices.

During the 2022 season, Insect Diagnostics has processed 54 inquiries from 2 states.  Identification requests fell into several categories, from requests out of general curiosity to much more specific identification needs.  The Home/Structural and General categories contained the bulk of the season’s inquiries (Figure 1).  During the season, a variety of clientele reached out to our program for identification assistance.  Homeowner’s submitted the most requests, however, government entities, commercial pest control and horticultural services utilized our service as well (Figure 2).

Figure 1. Percent of total inquiries received for each request category during the 2022 season.

Figure 2. Percent of total inquiries received from each clientele category during the 2022 season.

 

Insects identified this season varied greatly.  The colorful nymphs of green stink bugs caught quite a few homeowners’ eye this year and several instances of Kissing Bugs being found in homes caused concern (Figure 3).   The end of the season was dominated by many homeowners requesting identification of elm leaf beetles which have begun searching for overwintering spots inside homes and barns.

Figure 3. One of several Triatomine bugs (“Kissing Bugs”) submitted this year. A vector of Chagas Disease in extreme southerly locations of the United States and the tropics, but not of concern in Kansas.

 

The main season for insect activity may be ending, but the Insect Diagnostics Program will continue to operate and accept online inquiries throughout the fall and winter.  If you need insect identification assistance, submit a request at https://entomology.k-state.edu/extension/diagnostician/.

Army Cutworm Moths Still Flying in Southwest Kansas

–by Anthony Zukoff – Entomology Southwest Research and Extension Center
Garden City, KS

Noticeable numbers of army cutworm moths, also called Miller moths, have been observed in a couple locations in western Kansas this year.  Army cutworms are late fall and early spring pests of several Kansas crops, especially wheat.  These moths begin migrating into Kansas and neighboring states in the fall from their over-summering locations in the Rocky Mountains.  This year, moths began showing up in western Kansas during the first week of September.  In the last six weeks, over 1600 moths have been collected in pheromone traps at a location in Finney County.  Trap counts of 800 or more moths in an area may indicate increased caterpillar activity the following spring.  Right now, females will be laying eggs on the soil surface of freshly cultivated, weedy or newly seeded winter wheat fields.  Each female can lay up to 1000 eggs or more.  After hatching, caterpillars will begin feeding and do so until cold weather forces them below ground.  However, it is possible for them to resume feeding on warmer winter days.  Caterpillars will complete their growth next spring and then burrow into the soil to pupate. Sexually immature adults emerge in late spring and migrate back to the mountains for summer.  Fields should be scouted during warm periods between February and April.  Fields under stressful conditions, such as the current drought, may suffer economic damage with only 1-2 caterpillars per square foot. Typically, treatment will not be necessary until populations average 4-5 per square foot and well-tillered fields under good growing conditions can tolerate up to 10 per square foot without measurable yield loss. More information regarding control options for this pest in wheat and other crops can be found in the KSRE Insect Management Guides.

Army cutworm moths in a pheromone trap in Finney County

 

 

 

 

Correction to Sorghum Pests Article in Aug. 26, 2022 Newsletter

–by Jeff Whitworth – Field Crop Entomologist

Figure 1 should have been:

Figure 1: Sorghum (Sugarcane) aphids

Aphids are rapidly increasing around South Central and North Central KS., both corn leaf aphids (as seen in the Fig 2 in last week’s newsletter) which was miss labeled as sorghum (formerly sugarcane) aphids! These sorghum (sugarcane) aphids are rapidly increasing as seen in Fig 1 here (which was only a 2-week-old infestation) as are corn leaf aphids (again-seen in Fig 2 from last week’s Newsletter).

Figure 2:  Corn leaf aphids

Thus, monitoring should continue for these aphid populations, especially since, as yet, there do not seem to be many beneficials, see Fig 3 (ladybeetle larva decimating aphid nymphs) in most fields monitored.

 

Figure 3: Ladybeetle larva feeding on aphid nymphs

Sorghum Pests

–by Jeff Whitworth — Field Crop Entomology

 

Sorghum is really struggling across north and south-central Kansas, due to the hot dry conditions. Much is, or just has, started to head out and because of these hot /dry conditions we are seeing quite a lot of incomplete or nonuniform development, even within fields. This makes management decisions for “headworms” even more difficult– but fortunately, at least so far, “headworm” populations have not been much of a problem. Remember, sorghum is vulnerable to “headworm” feeding mainly between flowering and soft dough. We are continuing to see sorghum aphids (sugarcane aphids) migrate into Kansas, as EVERY field monitored in the last 7 days had various levels of infestation, from winged females just starting to produce nymphs (see fig. 1), to fields which have been infested for a week or two (see fig. 2), to a few fields that have substantial populations (see fig. 3 by Marvin Pipes). So far, beneficials seem to be helping to keep most of these aphid populations below treatment thresholds. However, monitoring should continue as these aphids will continue migrating into the state until the advent of much cooler weather.

Figure 1: Winged female sugarcane aphid + nymphs

Figure 2: Sugarcane aphid non-winged adults and nymphs

 

Figure 3: Substantial sugarcane aphid infestation

Soybean Pests

–by Jeff Whitworth — Field Crop Entomologist

The ongoing hot dry conditions seem to be starting to significantly stress many dryland crops. Then when you add in the stress of an insect pest it can really cause problems. Right now, blister beetles and Dectes stem borers are very active and causing concerns. Many growers seem to be confusing the two–adult Dectes with blister beetles–with good reason, as some blister beetle adults are similarly colored and shaped somewhat like adult stem borers. The two blister beetles most commonly confused with Dectes stem borer adults are shown here at the top, and just above (see fig. 1) a stem borer adult (photo by JR Ewing). Blister beetles may cause some defoliation by eating leaf tissue but it is usually insignificant. However, Dectes are currently still depositing eggs in soybean petioles, and have been for 2-3 weeks, where the small larvae hatch and start boring into the stem, most often causing the stem to die (see fig 2). However, the larvae continue this tunneling/boring into the main stem (see fig 3) and eventually end up just below ground where they remain through the winter.  (Figures 2 & 3 pictures provided by Sean Mills)

Figure 1: Two adult blister beetles on the top-adult and adult Dectes stem borer at the bottom left.

Figure 2: Crop damage from Dectes stem borers

 

Figure 3: Tunneling/boring stem damage

 

 

 

 

 

Garden Webworms

–by Jeff Whitworth — Field Crop Entomologist

Garden webworms (fig. 2) have just about finished feeding on soybeans and/or alfalfa (where they have been much less noticeable). They will pupate in the soil for the next 4-7 days then the moths will emerge to start depositing eggs in acceptable host plants. From a crop perspective this time of year, hopefully they will have little impact as the soybeans have developed far enough that these worms won’t defoliate enough to affect yield. But the really late-planted soybeans or those that may be moisture stressed may still have some concern, so monitoring should include these defoliators starting soon.

 

Figure 2: Garden webworm mature larva (picture by Steve Freach)

 

 

Fall Armyworms

–by Jeff Whitworth – Field Crop Entomologist

Adult fall armyworms are moths (fig. 1) and have been reported from southern Kansas for about the last 2 weeks and probably will be in the rest of the state soon-if not already. A quick refresher relative to this pest: they normally do not overwinter in Kansas, but in the lower portions of southern states, and down into Mexico and Central America. The moths usually arrive in Kansas anywhere from mid-June to mid-July as they fly/are blown here on southern winds. Fall armyworms have a wide host range but in Kansas are most often a cause for concern in corn and/or sorghum and later sometimes in wheat depending on planting date and weather. Also, in Kansas, especially the last 2 years, brome has been seriously defoliated (in combination with armyworms) in many areas around the state. Armyworm larvae may be part of the “ragworm” complex of larvae feeding in the whorl of corn and/or sorghum and then later the next generation become part of the complex of “headworms” or larvae feeding in the sorghum head directly on the developing grain. So the moths are here, ovipositing and thus the larvae are, or soon will, be feeding on whatever host the eggs were deposited on. Fall armyworms were quite common (in combination with other species) in 2020 and 2021 and thus monitoring should be initiated in any potentially susceptible crops. For management considerations please refer to the 2022 KSU Insect Management Guide for the crop of interest.

(Photo of fall armyworm moths taken of a Riker mount provided by revered KSU Extension entomologist, now retired, Dr. Bob Bauernfeind).

 

Figure 1: Fall armyworm moths

 

 

Scout for headworms in sorghum from flowering into milk stage

–by J.P. Michaud, Professor of Entomology, Agricultural Research Center, Hays, KS

Relatively new, cost effective, and environmentally friendly products are available for controlling headworms in sorghum. These are pest-specific viruses, formulated as biological pesticides that can be sprayed on the same as any foliar insecticide, or delivered via overhead irrigation sprinklers. But application must be made early in the infestation, while the majority of larvae are still small. These products should not be used as rescue treatments, but an early application will ensure infections propagate naturally throughout the field and that reapplication will not be required.  Sold under the brand names Heligen® (for corn earworm) or Fawligen® (for fall armyworm), these products are highly specific, killing only the target pest, sparing beneficial insects, and using other insects as vectors to create a local ‘epizootic’ of disease in the field. Thus, there is no environmental impact of treating below threshold (conventionally one or more worms per head), and it is valid to use these products as a relatively low-cost insurance policy, especially in a year when earlier sorghum to the south is already experiencing fall armyworm damage.

 

Farmers should be aware that many of the generic pesticides that might appear attractive on the basis of low cost are now much less effective against these pests, due to their repeated exposure to the same modes of action on many different crops over the years. In contrast, there are no known cases of pests evolving resistance to a virus, and unlike fungal pathogens, virus infections do not require humidity or leaf wetness. However, the product must be consumed by the pest, and larvae take up to a week to die, depending on temperature, but will stop feeding 48-72 hours post-injection. These virus formulations are also compatible with tank mixes of other materials, provided pH is held below 8.0, and combinations of both products are available if both species of headworms are present. More information is available from the supplier:

https://www.agbitech.us/

 

 

Green June Beetle Adult

–by Raymond Cloyd — Horticultural Entomologist

 

Green June beetle, Cotinis nitida, adults are flying around in massive numbers over both managed and unmanaged grassy areas. Green June beetle adults are erratic flyers and occasionally bump into people and objects. Adults are 3/4 to 1.0 inch long, velvety-green, with yellow-orange margins extend lengthwise on the front wings (Figure 1). The underside of the body is shiny and metallic green or gold. Adults fly around for several weeks from July through August. Green June beetle adults are sometimes mistaken for Japanese beetle, Popilla japonica, adults; however, they really do not look alike.

Figure 1. Green June Beetle Adult (Raymond Cloyd, KSU)

Green June beetle has a one-year life cycle, overwintering as a mature larva or grub in the soil. Adults typically emerge from late-June through early-July and are active during the day, resting at night on plants, in thatch, or in compost. Adults produce a sound when flying that is similar to bumble bees. Adults feed on ripening fruits and corn tassels, and may feed on the leaves of oak and maple trees. Male green June beetles swarm in the morning, flying to-and-fro just above managed and/or unmanaged grassy areas where females are located. The females emit an odor or pheromone that attracts the males. Clusters of beetles may be seen on the soil surface or in grassy areas with several males attempting to mate with a single female. After mating, females lay clusters of 10 to 30 eggs in moist soil with a high organic matter content. The larvae emerge (eclose) from eggs in approximately two weeks and feed near the soil surface. Larvae are 3/8 of an inch (early instars) to 1-1/2 (later instars) long and have the distinct characteristic of crawling on their back (Figure 2). Larvae primarily feed on organic matter in thatch or grass-clippings.

 

Figure 2. Green June Beetle Larva Crawling On Back (Raymond Cloyd, KSU)

 

For more information on how to manage green June beetle adults and larvae refer to the following extension publication:

 

Green June Beetle: Insect Pest of Turfgrass (MF3600 March 2022)

https://www.bookstore.ksre.ksu.edu/pubs/MF3600.pdf

Chinch Bugs

–by Jeff Whitworth — Field Crop Entomologist

 

Chinch bug populations seem to be increasing throughout south central and north central Kansas. Adults are currently very actively feeding, but more importantly, depositing eggs. This has been going on for the last couple of weeks in both corn and sorghum, which are still vulnerable to this chinch bug feeding, especially in later planted sorghum under hot dry conditions. Much sorghum is in the whorl stage or just starting to head out. Chinch bugs are usually difficult to control, but are especially difficult during these growth stages because, for the most part, the chinch bugs are feeding in and around the base of the plants and behind leaf sheaves. Either way they are relatively well protected from insecticides. The younger, tiny chinch bug nymphs are reddish with a white stripe while the older instar nymphs turn gray with a white stripe (see fig). For treatment recommendations please refer to the 2022 KSU Sorghum Insect Management Guide: https://www.bookstore.ksre.ksu.edu/pubs/MF742.pdf