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Extension Entomology

Cicada Killer

Posted on by Sharon Schroll

–by Raymond Cloyd — Horticultural Entomologist

We are receiving inquiries regarding large wasps flying around in landscapes and gardens. These large wasps are the Eastern cicada killer, Sphecius speciosus. Cicada killer adults are approximately 2.0 inches long and black with yellow-banded markings on the abdomen. The head and transparent wings are red-brown (Figure 1). Cicada killers are not dangerous, but they are intimidating; especially the males. Cicada killers are solitary wasps, not social wasps like yellowjackets. Adults live up to 75 days from July through September, and feed on flower nectar and plant fluids.

Figure 1. Cicada Killer Adult (Raymond Cloyd, KSU)

A female cicada killer will dig a 6 to 10-inch burrow (1/2 inch in diameter) in the soil; usually in sandy or loose soil. A pile of sand or soil, depending on soil type, will surround the entrance. Afterwards, cicada killer females search for dog days cicada, Tibicen pruinosa, adults located on the trunks and lower branches of trees. The female stings an adult cicada using her ovipositor (egg-laying device), flips the cicada over, straddles the cicada, and then transports the immobilized or paralyzed cicada back to the burrow in the soil (Figures 2 and 3). Each burrow may contain three to four cells with one or two cicadas. The dead cicada serves as a food source for the cicada killer larvae, which are legless and grub-like. A female will lay one egg per cicada if the egg is unfertilized. Larvae that emerge from unfertilized eggs are males whereas larvae that emerge from fertilized eggs are females and are provided with two cicadas. Larvae emerge (eclose) from eggs in two to three days and feed on paralyzed cicadas. The female will eventually cover the burrow, dig another one, and repeat the process. Full-grown larvae overwinter inside silken cases, pupate in spring, and adults emerge from July through August. There is one generation per year in Kansas.

Figure 2. Cicada Killer Female Transporting A Paralyzed Cicada To Her Nest (Raymond Cloyd, KSU)

 

Figure 3. Cicada Killer Adult Female With Dead Cicada

Cicada killers are an urban nuisance pest, especially when large numbers are nesting in bare areas, in turfgrass, or around a structure. People are generally concerned because cicada killers resemble giant yellowjackets or they think cicada killers are the so-called “Murder Hornet”. However, in general, cicada killers will not sting an individual. Wasp and bee female stingers are modified egg-laying devices (ovipositors), so males cannot sting. Females may sting if they going to be stepped on with bare feet or grabbed with bare hands.

Male cicada killers establish aerial territories and patrol for intruders. A male cicada killer wards-off other males that enter his territory and attempt to mate with females. An individual that walks into the territory is typically confronted by a very large wasp hovering in front of the face that ‘zips’ to the side and back. However, after determining that the intruder is not a rival or a threat, the male cicada killer ignores the individual. Nonetheless, an individual walking across a lawn, fairway, or other area where cicada killers are nesting, will experience the same treatment through each male’s territory. Sometimes there can be up to 20 cicada killer males in one area. After females have departed the nest, then males will eventually leave.

Cicada killers are common in areas with bare soil, so mulching, planting ground covers, or sodding may reduce potential problems with cicada killer populations. Cicada killers can be a problem in well-maintained areas such as irrigated and regularly fertilized turfgrass. In addition, cicada killers can be a problem when nesting in areas accessible to or frequented by the public. Applying carbaryl or pyrethroid-based insecticides containing the active ingredients; permethrin, bifenthrin, cyfluthrin, and/or lambda-cyhalothrin to the burrowed (nesting) area may kill females in golf course sand traps. In home yards, cover sandboxes with a tarp when not in use to deter cicada killers. Sand below swings, jungle gyms, or other playground equipment should be replaced with bark mulch or shredded tires.

Managing cicada killers in baseball infields and volleyball courts is more difficult because people with minimal clothing and exposed skin are diving and sliding onto the soil. Consequently, the use of an insecticide may not be an option. However, in the case of a volleyball court, a geotextile fabric placed beneath the sand may create a barrier that prevents cicada killers from creating burrows.

 

 

Garden Webworms

Posted on by Sharon Schroll

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

Posted on by Sharon Schroll

–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

Posted on by Sharon Schroll

–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

Posted on by Sharon Schroll

–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

Posted on by Sharon Schroll

–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

 

The Soybean Gall Midge

Posted on by Sharon Schroll

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

 

The Soybean Gall Midge (Resseliella maxima) was first observed in Nebraska in 2011, but was not officially described as a new species until 2018 when this tiny fly established itself as an emerging pest of soybeans in South Dakota, Nebraska, Minnesota and Iowa.  New infestations have been documented every year since and its range has expanded into Missouri.  Soybean gall midge has been documented in Nebraska along the Kansas border as recently as 2021.  To date, soybean gall midge has not been documented in Kansas, however this pest should be actively scouted for during the growing season, especially in counties along the Nebraska border.  Losses from soybean gall midge infestation are due to plant death and lodging (Figure 1 Photo by Justin McMechan, UN-L).  Heavily infested fields have shown the potential for complete yield losses from the edge of the field up to 100 feet into the field and a 20% yield loss from 200 to 400 feet into the field.

Figure 1

Adults: tiny (2-3mm), delicate flies with an orange abdomen, slender bodies and mottled wings. Long legs are banded with alternating light and dark markings (Figure 2 Photo by Mitchell Helton, Iowa State University).

Figure 2

Larvae: small, legless, maggots that are clear to white-colored when young but turn bright orange when mature (Figure 3 Photo by Justin McMechan, UN-L).

 

Figure 3

Soybean gall midge overwinter as larvae in the first few inches of soil. After pupation in the early spring, adult midges emerge and lay their eggs on the lower portions of stems or at the base of soybean plants.  The eggs hatch and the larvae feed within the stems. Infestation does not occur until the V2 stage when natural fissures and cracks appear in stems allowing entry by larvae.  Infestation can continue into the reproductive growth stages. So far, there appears to be at least two generations per growing season.  The adult soybean gall midges do not feed on soybeans.

 

Scouting

Begin scouting soybean plants at the V2 growth stage.  Symptoms of infestation include:

  1. Wilting or dead soybeans along field edges with decreasing damage into the center of the field (Figure 4 Photo by Justin McMechan, UN-L)
  2. Darkening and swelling at the base of stems (Figure 5 Photo by Adam Varenhorst, SDSU)
  3. Brittle stems that break easily near their base
  4. Small orange larvae present in split open stems

Figure 4

Figure 5

Management

Being such a new pest, there are currently no published research-based management recommendations. On-farm studies in impacted states are examining the effects of cultural practices and insecticides on preventing losses.  Seed treatments have not shown to be effective.  Please report any occurrence of soybean gall midge to your local extension professional or contact the K-State Entomology Department.  The Soybean Gall Midge Alert Network (https://soybeangallmidge.org/) can be used to track developments regarding this new pest.

 

Control of Headworms in Kansas Sorghum –Research Spotlight

Posted on by Sharon Schroll

–by J.P. Michaud, Professor in Entomology–Agriculture Research Center, Hays, KS

Collaborative research in China was featured in this summer’s edition of American Entomologist, and is relevant to control of headworms in Kansas sorghum.

https://academic.oup.com/ae/article-abstract/68/2/4/6605209?redirectedFrom=fulltext

 

This work was done on ‘Old World bollworm’, H. armigera, but its biology is very similar to that of corn earworm, H. zea.

The mechanisms by which the virus manipulates host behavior described therein are likely the same as those used by the HzeNPV that is the organism in the Heligen product we are using to control corn earworm in sorghum.

Instead of trying to pupate in the soil, infected larvae climb to the tops of plants where they die, assisting in the dispersal of the virus.

Here is the full abstract:

 

Abstract

Baculoviruses can induce climbing behavior in their caterpillar hosts to ensure they die at elevated positions to enhance virus transmission, providing an excellent model to study parasitic manipulation of host behavior. Here, we demonstrate that climbing behavior occurs mostly during daylight hours, and that the height at death of Helicoverpa armigera single nucleopolyhedrovirus (HearNPV)-infected larvae increases with the height of the light source. Phototaxic and electroretinogram (ERG) responses were enhanced after HearNPV-infection in host larvae, and ablation of stemmata in infected larvae prevented both phototaxis and climbing behavior. Through transcriptome and quantitative PCR, we confirmed that two opsin genes (a blue light-sensitive gene, HaBL, and a long wave-sensitive gene, HaLW) as well as the TRPL (transient receptor potential-like channel protein) gene, all integral to the host’s visual perception pathway, were significantly up-regulated after HearNPV infection. Knockout of HaBL, HaLW, or TRPL genes using the CRISPR/Cas9 system resulted in significantly reduced ERG responses, phototaxis, and climbing behavior in HearNPV-infected larvae. These results reveal that HearNPV alters the expression of specific genes to hijack host visual perception at fundamental levels – photoreception and phototransduction – in order to induce climbing behavior in host larvae.

 

 

Grasshoppers

Posted on by Sharon Schroll

–by Jeff Whitworth — Field Crops Entomologist

Grasshoppers continue developing, mainly still in grassy/weedy areas, adjacent to crop fields.

These grasshoppers generally can fly for a short distance, but are not yet adults (see fig 3). As they continue feeding and developing however, and the hot/dry conditions continue, these grasshoppers will become adults, which means more mobile, and probably then fly to the more succulent crops nearby.

 

Figure 3: Grasshopper

 

Dectes Stem Borer

Posted on by Sharon Schroll

–by Jeff Whitworth — Field Crops Entomologist

 

 

Dectes stem borer adults have been active for about the past 3 weeks. Females have mated and started depositing eggs in stems for about the last 2 weeks. The small larvae are already causing an impact on young soybean plants (see fig2).

 

Figure 2: Soybean plant damaged by Dectes stem borer