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Extension Entomology

Category: Horticulture

Gorgone Checkerspot

–by Dr. Raymond Cloyd

Have you noticed the leaves of your sunflower (Helianthus annuus) plants being fed upon by caterpillars (Figure 1)? If so, the caterpillar in question is the gorgone checkerspot (Chlosyne gorgone). The caterpillar ranges in color from black to orange, with a black head and spines or barbs covering the body (Figure 2). The caterpillars feed on sunflowers and other related plants. The young caterpillars feed in groups (Figure 3) whereas the mature caterpillars, which are approximately 1.0 inch in length, feed individually (Figure 4). Third instar larvae will eventually search for a place to overwinter.

Figure 1. Gorgone Checkerspot Caterpillars Feeding On Sunflower Leaf (Raymond Cloyd, KSU)

Figure 2. Gorgone Checkerspot Caterpillar (Raymond Cloyd, KSU)

 

 

Figure 3. Young Gorgone Checkerspot Caterpillars Feeding In A Group (Raymond Cloyd, KSU)

Figure 4. Mature Gorgone Caterpillar (Raymond Cloyd, KSU)

If you see the caterpillars feeding on sunflower leaves and your plants can tolerate some feeding damage, then just leave them alone as the caterpillars will eventually develop, by means of complete metamorphosis, into beautiful butterflies.

 

ID to last week’s bug

–by Frannie Miller

Great garden digger wasp – The great garden digger wasp is a nonaggressive, large solitary wasp that digs nests in sandy soil. They are beneficial because they prey upon grasshoppers, aerate the soil, improve the soil’s water holding capacity, and help to pollinate flowers. These wasps have been quite active in one of my flower beds.

 

Cicada Killer…Not The Asian Giant Hornet

–by Dr. Raymond Cloyd

We are receiving inquiries regarding large wasps flying around. These are the Eastern cicada killer (Sphecius speciosus); not the Asian Giant Hornet (Vespa mandarinia). Cicada killer females search for, kill, and provision each cell within a nest located in the ground with a dog day cicada (Tibicen pruinosa) adult. The dead cicada is a food source for young cicada killer larvae. Cicada killers are an urban nuisance pest, especially when nesting in large numbers, 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 Asian giant hornet.

Cicada killers 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 ground-nesting solitary wasps, with the female digging a 6 to 10-inch burrow (1/2 inch in diameter) in the ground; usually in sandy or loose soil. A pile of sand or soil, depending on soil type, will surround the entrance.

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

Females search for and sting large insects such as a cicada or katydid, and then bring the immobilized or paralyzed prey back to the burrow (Figures 2 and 3).

 

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

Figure 3. Cicada Killer Adult Female With Dead Cicada

The female places prey into a chamber in the nest and then lays an egg on the body. Afterward, the female covers the burrow, digs another burrow, and repeats the process. A legless grub-like larva will emerge (eclose) from the egg and proceed to consume the prey. Full-grown larvae overwinter in the burrow, pupate in spring, and emerge as adults from July through August.

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 and ‘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. Nevertheless, 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. After females have left the nest then males will eventually leave.

Cicada killers, in general, will not sting an individual. Wasp and bee stingers are modified egg-laying devices (ovipositors), so males cannot sting. Females, however, may sting if crushed or if stepped on with bare feet, or grabbed with bare hands.

Cicada killers are common in areas with bare soil, so mulching, planting ground covers, or sodding may reduce issues with cicada killers. 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 insecticides containing the active ingredients; permethrin, bifenthrin, cyfluthrin, and/or lambda-cyhalothrin to the burrowed area will kill females in golf course sand traps. In home yards, sandboxes should be covered 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 challenging because people with minimal clothing and exposed skin are diving and sliding onto the ground; thus making it difficult to recommend using an insecticide. 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.

ID to last week’s bug

–by Frannie Miller

Brown blister beetle – This insect can be easily recognized as a blister beetle due to its elongated, cylindrical body shape. Blister beetles product a substance called cantharidin, which can produce nasty blisters if they are ingested or touched. There extensive feeding habits can defoliate garden plants as well as field crops. Learn more here: https://www.bookstore.ksre.ksu.edu/pubs/MF959.pdf

 

WHEEL BUGS

–by Dr. Jeff Whitworth

We have had several reports about wheel bugs (fig. 1) this year from all parts of the state. These bugs are always around but are very shy, well camouflaged, slow deliberate moving, and relatively large bodied. They are predacious, often feeding on lepidoptera (butterfly/moth) larvae that are considered pests. They, thus, are considered beneficial but there just are not enough of them to really cause an impact on pests. They look relatively imposing because of their size-and they should be avoided, although they do rarely bite people, but when they do it is an EXTREMELY painful experience!

Figure 1. Wheel bug (picture by Cody Wyckoff)

Green June Beetle Adult

–by Dr. Raymond Cloyd

Green June beetle, Cotinis nitida, adults are flying around in massive numbers near managed and/or unmanaged grassy areas, and occasionally ‘bumping’ into people and objects. Adults are 3/4 to 1.0 inch long, velvety-green, and tinged with yellow-brown coloration (Figures 1 and 2).

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

 

Figure 2. Green June Beetle Adult (Raymond Cloyd, KSU)

Green stripes with yellow-orange margins extend lengthwise on the front wings. The underside of the body is distinctly shiny and metallic green or gold. Adults resemble ‘dive bombers’ flying around for several weeks in July. Green June beetle adults are sometimes confused with Japanese beetle (Popilla japonica) adults; however, they really do not look alike (Figures 3 and 4).

 

 

Figure 3. Green June Beetle Adult (Raymond Cloyd, KSU)

 

Figure 4. Japanese Beetle Adult (Raymond Cloyd, KSU)

Green June beetle has a one-year life cycle, and overwinters as a mature larva or grub. Adults generally emerge in late-June and are active during the day, resting at night on plants, in thatch, or in compost. Adults produce a sound similar to that of bumble bees. Adults feed on ripening fruits (Figure 5) and corn tassels, and may feed on the leaves of oak and maple trees. Male beetles swarm in the morning, ‘dive bombing’ to-and-fro just above managed and/or unmanaged grassy areas where females are located. Females emit a pheromone that attracts the males. Clusters of beetles may be seen on the surface of the soil or in grassy areas with several males attempting to mate with a single female, resulting in an ‘insect orgy.’ Mated females that survive the ‘experience’ will lay clusters of 10 to 30 eggs in moist soil that contains high amount of organic matter.

Figure 5. Green June Beetle Adults Feeding On Fruit (Raymond Cloyd, KSU)