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Extension Entomology

Category: Household

Pine Bark Adelgid

–by Dr. Raymond Cloyd

Have you noticed your eastern white pine (Pinus strobus) trees looking like they are covered with snow? Well, the trees are not covered with snow—they are infested with the pine bark adelgid (Pineus strobi). The pine bark adelgid is an insect pest that primarily feeds on eastern white pine, but will also feed on Austrian (Pinus nigra), and scots (Pinus sylvestris) pines.

Pine bark adelgid adults are approximately 3.0 mm (1/9 inch) in length, black, wingless, and covered by a white, fluffy wax (Figure 1).

Figure 1. White Woolly Tufts Covering Pine Bark Adelgids (Raymond Cloyd, KSU)

Immature females that have been overwintering mature in April and lay eggs on the bark of pine trees. Nymphs that emerge (eclose) from eggs are either winged or wingless. Adelgid nymphs and adults possess very long mouthparts (stylets) that allow them to penetrate wood beneath the bark and feed within the phloem (food-conducting tissues). Nymphs secrete large quantities of wax that solidifies into white woolly tufts that cover the body. The woolly white wax produced by pine bark adelgids can cover large areas of pine trees, including the main trunk, branches, and shoots (Figure 2). In addition, pine bark adelgids secrete honeydew, which is a clear, sticky liquid that serves as a growing substrate for black sooty mold.

Figure 2. Woolly White Wax Covering A Branch (Raymond Cloyd, KSU)

Nymphs and adults are most prevalent on the trunk, branches, and shoots of older (over 10 years old) eastern white pines. Furthermore, infestations of pine bark adelgid may be more noticeable on the underside of branches. Pine bark adelgid overwinters as an immature female nymph located on the bark that matures into an adult in spring. There may be several generations per year.

A forceful (high-pressure) water spray can be used to dislodge adelgids from pine trees. Contact insecticides such insecticidal soaps (potassium salts of fatty acids) or horticultural oils (petroleum- or mineral-based) applied from April through May when pine bark adelgids are active may be effective in suppressing populations and mitigating potential damage to pine trees. Dormant oil applications can be made in the fall through spring to kill overwintering nymphs. Thorough coverage of all plant parts is important. Systemic insecticides applied to the soil in early spring may be effective in preventing or minimizing infestations of the pine bark adelgid. There are a number of beneficial insects that feed on pine bark adelgid including ladybird beetles, lacewings, and syrphid fly larvae. However, these beneficial insects may not effectively regulate pine bark adelgid populations to prevent the occurrence of heavy infestations.

Insecticide Active Ingredients Registered For Use Against Bagworms

–by Dr. Raymond Cloyd

 

Bagworm Cases Are ≤ 3/4 Inches Long

* Bacillus thuringiensis subsp. kurstaki

* Spinosad

 

When Bagworm Cases Are > 3/4 Inches Long

* Bifenthrin

* Carbaryl

* Clarified hydrophobic extract of neem oil

* β-cyfluthrin

* Gamma-cyhalothrin

* Lambda-cyhalothrin

* Malathion

* Permethrin

* Tau-fluvalinate

* Zeta-cypermethrin

 

Note: these active ingredients can be used when bagworm cases are ≤3/4; however, they are more harmful to beneficial insects and pollinators.

 

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)