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Landscape Insects

This laboratory session covers selected insects of trees, shrubs, and turf. To provide some structure

for a very broad range of plants and insects, the specimens and materials provided in this lab

session are arranged in broad categories -- defoliators, sap-sucking insects, gall-makers, wood

borers and bark beetles, and turf insects. Within these groups a few common examples are

presented as representatives of many, many more species with similar life histories. In the previous

lab on field crop insects, specific sampling methods and thresholds were summarized because the

damage and the economic impact of that damage are moderately well established for field crop

pests. Well defined thresholds for control of landscape insects are much less common.

Defoliators

eastern tent caterpillar, Malacosoma americanum (Fabr.) (Lepidoptera: Lasiocampidae),

and fall webworm, Hyphantria cunea (Drury) (Lepidoptera: Arctiidae)

gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lasiocampidae)

bagworm, Thyridopteryx ephemeraeformis (Haworth) (Lepidoptera: Psychidae)

Sap-sucking insects

leafhoppers, including potato leafhopper, Empoasca fabae (Harris) (Hemiptera:

Cicadellidae)

aphids (Hemiptera: Aphididae)

scale insects, including cottony maple scale, Pulvinaria innumerabilis, (Rathvon)

(Hemiptera: Coccidae), pine needle scale, Chionaspis pinifoliae (Fitch) (Hemiptera:

Diaspididae), and oystershell scale, Lepidosaphes ulmi (Linnaeus) (Hemiptera:

Diaspididae)

Gall-makers

hackberry psyllid, Pachypsylla celtidismamma (Riley) (Hemiptera: Psyllidae)

horned oak gall wasp, Callirhytis cornigera (Osten Sacken) (Hymenoptera: Cynipidae)

maple bladder gall and maple spindle gall mites, Vasates spp (Acari: Eriophyidae)

Wood borers and bark beetles

Longhorned beetles (Coleoptera: Cerambycidae): Asian longhorned beetle, Anoplophora

glabripennis (Motschulsky) and pine sawyers, Monochamus spp.

Metallic wood boring beetles (Coleoptera: Buprestidae): emerald ash borer, Agrilus

planipennis Fairmaire, and bronze birch borer, Agrilus anxius Gory

ash/lilac borer, Podosesia syringae (Harris) (Lepidoptera: Sesiidae)

bark beetles (Coleoptera: Curculionidae: Scolitinae): smaller European elm bark beetle,

Scolytus multistriatus (Marsham), and mountain pine beetle, Dendroctonus ponderosae

Hopkins

Turf insects

White grubs (Coleoptera: Scarabaeidae): annual white grub / masked chafer, Cyclocephala

spp., and Japanese beetle, Popillia japonica Newman

Sod webworms, Crambus spp. and others (Lepidoptera: Crambidae)

In addition to these pest species, a few other insects of common interest are presented with this lab:

Honey bees, bumble bees, carpenter bees, and sweat bees

Yellow jackets and the bald-faced hornet

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Defoliators

1. Eastern tent caterpillar and fall webworm

Among the most common defoliators of trees and shrubs in Illinois are the eastern tent caterpillar,

and the fall webworm. Tent caterpillars hatch in the spring from overwintered eggs, and larvae

feed on trees as they first leaf out. Fall webworms overwinter as pupae, and moths emerge and lay

eggs in early summer. Larval "nests" of the fall webworm become evident in late summer.

Above left: Eastern tent caterpillar egg mass (Univ. of Illinois). Above center: tent caterpillars on webbing (Univ. of Wisconsin). Above

right: Eastern (L) and forest tent caterpillar larvae (Ohio State Univ.). Below: Eastern tent caterpillar moth.

Above: Fall webworm adult(left), larva (center), and webbing (right) (Oklahoma State University).

For the eastern tent caterpillar, notice how egg masses surround a small twig and are covered with a

shiny, dark brown coating. Eastern tent caterpillars secrete webbing or “tents” at the crotch of

branches, and although the larvae rest within these tents, they leave them to feed on exposed foliage

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anywhere on the host plant. In contrast, fall webworm larvae make nests at the tips of branches,

and they feed on the foliage enclosed within their webbing.

Outbreaks of tent caterpillars have been linked to mare reproductive loss syndrome in Kentucky. It

appears that mares accidentally consume larvae and that the hairs on the larvae imbed in the lining

of the alimentary canal and trigger bacterial infections that lead to miscarriages

(http://www.ca.uky.edu/gluck/NewsMedAlertETC.asp).

In most instances infestations of tent caterpillars or fall webworms are unsightly but not extremely

harmful to the host trees. These insects can be controlled by removing nests (of fall webworm) or

tents when larvae of tent caterpillars are resting on the webbing. Bacillus thuringiensis kurstaki (or

aizawai) (Bt) is often recommended where insecticides must be used because sprays containing

this bacteria are toxic only to caterpillars.

References:

Bessin, R. 2003. Eastern Tent Caterpillar.

http://www.ca.uky.edu/entomology/entfacts/ef423.asp

Mazzey, K., and M. Maziuk. Undated. Fall Webworm.

http://woodypests.cas.psu.edu/FactSheets/InsectFactSheets/html/Fall_Webworm.html

2. Gypsy moth.

Another well-known example of a Lepidopteran defoliator is the gypsy moth. This insect was

introduced into North America in 1869 by a French naturalist trying to start a new silk industry. It

has since spread to threaten a wide range of deciduous trees. It winters in the egg stage, and eggs

may be laid on a variety of surfaces ... including travel trailers, moving vans, and other vehicles. As

a result, its movement to new areas is aided by its hitch-hiking as well as its local dispersal. This

hitch-hiking dispersal is especially important because adult females do not fly (even though they

have wings).

Left: Gypsy moth adult male (darker) and female (Penn State Univ.) Center: Female and egg mass (US Forest Service). Right: Gypsy moth larva (US Forest Service).

Read the brief fact sheet provided at this station to understand more about this insect. The web site

that presents this fact sheet (at http://www.fs.fed.us/ne/morgantown/4557/gmoth/) includes links

with more information on its life history, its natural enemies, its management, and its historic and

predicted spread. The maps presented here are taken from this web site.

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Reference:

Liebold, S. 2003 and updates. Gypsy Moth in North America.

http://www.fs.fed.us/ne/morgantown/4557/gmoth/

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3. Bagworm.

We usually think of Lepidopterans as butterflies or moths with well developed wings and as larvae

that crawl around, quite visible on leaf surfaces. There are lots of exceptions to this generalization,

however, and the bagworm is a common one. Bagworm larvae construct cases of foliar debris

around themselves and feed from within this protective "bag". Females remain “larvaiform” and

mate at the opening of their larval case, then they lay eggs (500 – 1,000 apiece) within it. In central

Illinois, bagworms are most common on arborvitae and similar conifers, but they also may feed on

several common broad-leafed trees as well.

Left: bagworm larva and bag (University of Nebraska). Right: adult male (E.D. Cashatt, Illinois State Museum).

Like many other arthropods that are wingless as adult females, bagworms still have a means of

dispersal other than crawling. Young larvae, upon hatching from overwintered eggs, spin a silken

thread and hang from it to attach to passing animals or to be windblown to new locations – this

“ballooning” behavior is not unlike that seen in the twospotted spider mite.

Hand-picking is often advised as a means of controlling bagworms on relatively small plants.

Because larvae are concealed in a bag constructed of plant debris, they are not highly susceptible to

conventional insecticides. Applications of insecticides that contain Bacillus thuringienis (kurstaki

or aizawai) can be the most effective, as larvae consume spores and toxins when they feed on

treated foliage.

References:

Mazzey, K., and M. Masiuk. Undated. Bagworm.

http://woodypests.cas.psu.edu/FactSheets/InsectFactSheets/html/Bagworm.html

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Sap-sucking Insects

Below are a few examples of the many sap-sucking insects that infest trees and shrubs, but indeed only

a very few. For the families presented here (Aphididae, Diaspididae, and Coccidae), there are dozens if

not hundreds of species that feed on trees and shrubs. Moreover, there are several other families of sap-

sucking insects not presented here at all – plant bugs, spittlebugs/froghoppers, tree hoppers, plant

hoppers, psyllids, and more. The reference displayed in lab – Insects that Feed on Trees and Shrubs,

by Johnson and Lyon – provides a good overview and excellent photos.

4. Leafhoppers, including potato leafhopper.

Many leafhoppers feed on a wide range of trees and shrubs. As noted in the lab on field crop insects,

when leafhoppers insert their stylets into plant foliage, they may injure plants in one of four ways: (1)

direct removal of cell contents, reducing photosynthate availability; (2) transfer of plant pathogens (3)

injection of salivary toxins that kill cells around feeding sites; and (4) secretion of honeydew that

supports growth of sooty molds on plants surfaces. In trees and shrubs, a few examples include: Rose

leafhopper and white apple leafhopper feed on roses, apples, and many other plants, removing

chlorophyll and leaving white, stippled areas on leaves; their honeydew secretions also contribute to

sooty mold on foliage. Leafhoppers known as sharpshooters in the genus Graphocephala (including

rhododendron leafhopper) are known to carry pathogenic microorganisms. The potato leafhopper is a

serious pest of several trees and shrubs, including maples, birch, and redbud. The salivary toxins it

injects when it feeds cause leaf cupping and curling and the cessation or distortion of growth of new

shoots.

Potato leafhopper injury on apple (left) (West Virginia University) and maple (University of Illinois).

Use the reference below and look over pages 412-419 in Insects that Feed on Trees and Shrubs for

more information about leafhoppers.

Reference:

Anon. Undated. Leafhoppers. http://www.entomology.umn.edu/cues/Web/162LeafHopper.pdf

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5. Aphids (and adelgids).

Spirea aphid on spirea (Jim Schuster, University of Illinois)

http://www.urbanext.uiuc.edu/shrubselector/detail_problem.cfm?PathogenID=102

First, remember “who” the aphids are … pear-shaped insects that may be winged or wingless as adults,

their sucking stylet appears to originate from the base of the head, and cornicles (tailpipes) near the end

of the abdomen are used in their identification. Also remember that, in general, eggs are part of the life

cycle only for overwintering; they hatch into females that develop to the adult stage and without mating

give birth to more live females (parthenogenesis). Many develop for a few generations in the spring on

a tree or shrub host and then migrate to an annual plant during the summer (soybean aphid winters on

buckthorn, a woody shrub), but others remain on their woody host(s) all year-around (such as giant

willow aphid, spirea aphid, and rose aphid).

Aphid feeding on new leaves and shoots may cause leaf curling and distortion; large numbers of aphids

removing sap from plants can reduce growth and vigor. The sticky liquid excreted by aphids

(honeydew) is sometimes a nuisance, and it provides energy for the growth of sooty molds that reduce

the attractiveness of foliage. Many natural enemies attack aphids on trees and shrubs.

Woolly aphids and adelgids that feed on pine and spruce (family Adelgidae) secrete white, waxy

coatings that cover their bodies; these insects commonly cause galls, as do some other aphids.

Note the specimen(s) presented, and use the reference provided to answer any questions in your

assignment. Also briefly look over pages 74-85 and 292-317 in Insects that Feed on Trees and Shrubs

for more examples of aphids and adelgids on woody plants. .

Reference:

Cranshaw, W. 2004. Aphids on Shade Trees and Ornamentals.

http://www.ext.colostate.edu/pubs/insect/05511.pdf

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6. Scale insects: soft scales (Coccidae) & armored scales (Diaspididae).

Again, realize how little we scratch the surface on scale insects with the few examples we cover in this

lab assignment. A quick scan of Armored Scale Insect Pests of Trees and Shrubs by Miller and

Davidson (well over 400 pages, with lots of great illustrations and identification guides) gives you an

idea of how diverse just the armored scales are (without covering the soft scales). Several cottony

scales and armored scales are pests of trees and shrubs. Specimens of cottony maple scale (a soft scale),

pine needle scale, and oystershell scale are provided along with a reference that provides a brief

summary on each of these insects.

Top left: cottony maple scale (North Dakota State University); top right: oystershell scale (University of Illinois); bottom left:

pine needle scale (and twice-stabbed lady beetle); bottom right: pine needle close-up showing small red crawlers. Bottom

photos from Cornell University.

See pages 115-116 and pages 265-268 in Armored Scale Insect Pests of Trees and Shrubs for close-

ups of pine needle scale and oystershell scale and scan the information about their life cycles. Also

look over examples of other scale insects.

Rarely are insecticides used regularly to control scale insects on trees and shrubs, but when they are,

successful control often depends on (1) timing applications so that a large percentage of the population

is in the crawler stage and exposed the chemical at or soon after application; (2) using “dormant oils” or

similar materials when a large portion of the population can be suffocated under scales by the oil film

deposited on trunks, branches, or twigs; or (3) using systemic insecticides that move into the plant sap

to kill scale insects as they feed.

Reference:

Wawryynski, R., and M. Ascerno. 2009. Scale Insects of Trees and Shrubs.

http://www1.extension.umn.edu/garden/insects/find/scales/

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Gall-making insects

7. Hackberry psyllid, horned oak gall wasp, maple bladder gall mite and maple

spindle gall mite. Galls are plant tissues that are produced in response to injury or infection. Insects and other arthropods

trigger gall production by feeding on or laying eggs into plant tissue. Homopterans (adelgids and

psyllids) and Hymenopterans (especially cynipids) are among the most common insects that are gall

inducers. Mites in the family Eriophyidae also cause a variety of leaf galls.

Left: Hackberry nipple gall (University of Kentucky). Right Horned oak gall (Oklahoma State University).

Left: Maple bladder gall (University of Kentucky). Right: Maple spindle gall (Ohio State University).

Examine the specimens provided for the four galls shown above, and briefly look over the other

examples of arthropod-induced galls. Check the fact sheet, Gall-Making Insects and Mites, to get an

idea of what insects cause common galls on woody plants.

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References:

Bogran, C.E., B.M. Drees, and J.L Hidgeons. 2006. Gall-making Insects and Mites.

http://insects.tamu.edu/extension/publications/epubs/e-397.cfm

Dixon, W.N. 2006. Gall Wasps, Callirhytis quercusclaviger (Ashmead) and Callirhytis cornigera

(Osten Sacken) (Insecta: Hymenoptera: Cynipidae). http://edis.ifas.ufl.edu/in664

Wood borers and bark beetles Many roundheaded wood borers and flatheaded wood borers develop in trees that are already in decline,

and although the trees may die following infestation, the wood borers seldom are the primary cause for

decline or death. The beetles that we know best as pests are the exceptions to this rule. For general

information on several roundheaded and flatheaded borers, see

http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5186647.pdf.

8. Longhorned beetles / roundheaded wood borers. Two examples of the more serious pests in the family Cerambycidae are presented at this station. One

is an introduced species that is an extremely serious pest that kills hardwood (deciduous) trees – the

Asian longhorned beetle. The other is a native genus, Monochamus, the pine sawyers. Larvae of these

beetles develop in conifers. Pine sawyers are serious pests of pines because they are vectors of

pinewood nematode.

Asian longhorned beetle adult (left) and emergence hole from tree trunk (right) (USDA Forest Service).

Asian longhorned beetle was first detected in North America in New York in 1996. It was found near

Ravenswood, IL, in 1998 and in New Jersey in 2004. New infestations were detected on Staten Island,

NY, in 2007. Infested wood has been found in warehouses in several areas around the country. Larvae

of this beetle tunnel in maple, birch, poplar, willow, ash, and elm (as well as other species), and their

feeding injury kills otherwise healthy trees. Where new infestations are found, susceptible trees in the

infested area are cut down and chipped or burned in efforts to eradicate this pest. Eradication efforts in

the Chicago area appear to have been successful, as no new beetles or infestations were detected there

in recent years.

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The pine sawyers are so named because the larvae make loud noises while cutting / feeding in wood.

They typically infest trees that are stressed or dying or recently dead trees, including trees that have

been cut or felled by storms. Young larvae feed near the surface, just below the inner bark, and older

larvae first go deeper into wood, then turn back toward the surface. On their own, too few pine sawyers

infest healthy trees to cause severe injury. However, where drought stress attracts these insects to

Austrian or Scotch pine, especially where these trees are grown in warm climates, sawyers can be

instrumental in the death of the trees because they carry a pathogenic nematode – pine wilt nematode –

that infests the vascular system and kills trees.

Pine sawyer, Monochamus spp., adult (left) and larva (right) (Oklahoma State University).

References:

USDA APHIS, 2007. Asian Longhorned Beetle: Questions and Answers.

http://www.aphis.usda.gov/publications/plant_health/content/printable_version/faq_alb_07.pdf.

Oklahoma State University. Undated.

http://www.ento.okstate.edu/ddd/insects/pinesawyerbeetle.htm.

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9. Flat headed wood borers / metallic wood-boring beetles.

Again we’ll cover a native species and an exotic species that are serious pests (even though many other

flatheaded wood borers infest trees only after they are already in decline). The bronze birch borer is a

native species; emerald ash borer is exotic.

Adult bronze birch borers are about ½ inch long and an iridescent brownish-black (bronze) in color.

Females typically lay eggs in bark crevices in June, and larvae that hatch from these eggs tunnel in

phloem and then xylem tissue to feed. Larvae may require one or two seasons to develop (depending

on location and temperatures), and they pupate in April or May. They are most prevalent in white

birch, paper birch, and yellow birch. Keeping these birch cultivars otherwise healthy (good planting

sites, irrigation, etc.) can reduce losses, but this insect can kill birch trees. River birch, Japanese birch,

and ‘Heritage’ birch are resistant to this insect.

Bronze birch borer symptoms of attack (left); adult beetle and emergence hole (right) (Ohio state University).

Emerald ash borer should be a familiar insect by now, as it has been the object of a great deal of press

in Illinois and elsewhere in the eastern U.S. over the last few years. The reference listed below

provides plenty of information on this insect’s appearance, life history, and origins … be sure to jot

down a brief summary of that information:

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

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Emerald ash borer larva (left) (Purdue University) and adult (right) (USDA).

Known distribution, September, 2013:

http://www.emeraldashborer.info/files/MultiState_EABpos.pdf

References:

Gibb, T., and C. Sadoff. 2007. Bronze Birch Borer.

http://extension.entm.purdue.edu/publications/E-50.pdf

Emerald Ash borer. http://www.emeraldashborer.info/index.cfm

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10. Ash/lilac borer.

Introductory coverage of clearwinged moths in general and the ash and lilac borer(s) specifically is

presented in the reference provided. Several clearwinged moth larvae are very damaging to ornamental

trees and shrubs. The peachtree borer and lesser peachtree borer damage flowering plums; viburnum

borer damages viburnum, and lilac / ash borer damages ash and lilac. These insects typically attack

otherwise healthy trees, and their damage can kill trees.

Controlling these insects with insecticides applied as trunk sprays is possible and practical, but

applications must be made before larvae have entered the tree, and extended periods of moth flight and

egg-laying require repeated applications.

Lilac borer adult (left) (Kansas State University) and larva (right) (Ohio State University).

Reference:

Clearwing borers. http://www.entomology.umn.edu/cues/Web/088ClearwingBorers.pdf

Bark beetles

11. Smaller European elm bark beetle and mountain pine beetle.

Bark beetle larvae tunnel just beneath the bark of trees, destroying the cambium. Many species attack

trees that are weakened or dead, but some species are pests of otherwise healthy trees, especially when

beetle populations are extremely high and their attack overcomes tree defenses.

Bark beetles carry fungi that grow in their tunnels ... these fungal colonies serve as food for the beetles. In

some instances, the fungi are serious pathogens of the host tree as well. This is true for the Dutch elm

disease pathogen, Ophiostoma ulmi, the fungus carried by the elm bark beetles. The native elm bark

beetle and the smaller European elm bark beetle both carry the fungus that causes Dutch elm disease.

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The European elm bark beetle was first detected in the U.S. in 1909, and the Dutch elm disease fungus

was detected first in 1930. By the 1960s and 70s the disease had wiped out almost all mature American

elms in North America.

Smaller European elm bark beetle (left) (Oregon State University) and larval galleries (right) (University of Illinois).

Mountain pine beetle (Colorado State Univ.)

Mountain pine beetle is a very widespread bark beetle in the western United States. For those who have

traveled to Colorado or other mountain states in recent years and noticed large areas of coniferous forest

where the needles are brown and the trees are dying, know that drought conditions followed by mountain

pine beetle infestations are the primary causes. Don’t devote a lot of time to learning lots of details on

this insect ... just be aware of it, know that it is an important component of western forest ecosystems and

that outbreaks can have devastating effects.

References:

Cornell University. 2005. Dutch Elm Disease.

http://plantclinic.cornell.edu/factsheets/dutchelmdisease.pdf

Leatherman, D. 2005. Mountain pine beetle. Colorado State University,

http://www.ext.colostate.edu/pubs/insect/05528.html.

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Turf insects

12. White grubs.

White grubs are the larvae of beetles in the family Scarabaeidae. In Illinois and much of the north

central United States, the northern and southern masked chafers ("annual white grubs") are the most

common and damaging species. In the eastern United States, Japanese beetle larvae are more

common. As the Japanese beetle has spread across Illinois, it has become more important as a pest

of lawns and turf.

First, look over the specimens of some common adult beetles in the family Scarabeidae provided at

this station. These species are at least somewhat associated with turf; many other species develop

in dung as larvae instead of feeding on plant roots. Examine the Ohio State University fact sheet

that compares the characteristics of these and other species.

List the species exhibited here as adults:

___________________________________________________________________________

___________________________________________________________________________

Next, look over the illustrations (in the Ohio State University fact sheet) that show the raster

patterns on larvae of common species, and identify the specimens provided. If given this

identification guide and a specimen of one of these larvae for the final lab exam, you should be able

to use the key to identify it.

Describe in your own words the difference in the raster pattern on larvae of annual white grub

(Cyclocephala spp.) vs. Japanese beetle (Popillia japonica) vs. perennial (=true) white grub

(Phyllophaga spp.). Which of these species is/are the most common pest grubs in Illinois lawns?

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

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Turf rolled back to reveal grubs (Kansas State University).

Masked chafer (annual white grub) life cycle and damage: Partially mature larvae move down a

few inches in the soil to overwinter, return to the root zone to feed in the spring, then pupate in mid

to late May. Adult beetles emerge in June and July (sometimes triggered by rains), mating occurs,

and females lay eggs, particularly in grass growing in moist, well-drained, fertile soils. Larvae

hatch and begin feeding in August, and they continue to feed well into the fall. They chew off and

consume grass roots just below the soil - thatch interface, and damage to turf is most apparent in

August and September, because moisture stress often accentuates the root injury at this time.

Severely damaged turf may show dead patches that can be lifted or rolled back like a carpet.

Life cycle, masked chafer / annual white grub (University of Nebraska).

Sampling and control: Lawns and turf can be sampled for the larvae of masked chafers in August

to determine whether or not control is needed. Scouts cut through turf on 3 sides of a 6-inch or 12-

inch sampling frame, then roll it back (sometimes cutting roots to make this possible) to check for

and count larvae. Thresholds vary among turfgrass species and according to the vigor of turf at any

given site, but insecticides are often recommended if counts exceed 8 to 10 grubs per square foot

(maybe up to 20 in vigorous turf).

Lawns and turf that are watered frequently in late June and July are especially attractive to egg-

laying beetles (especially during very dry summers), and these sites may be heavily infested.

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Beetles are also attracted to lights, and egg-laying can be concentrated under outdoor lights in

residential lawns.

The life cycle of the Japanese beetle is very similar to that of the annual white grub, although this

species may cause a little more damage as it resumes feeding in the spring of the year. Note in the

University of Kentucky fact sheet on this insect the list of landscape trees and shrubs that damaged

severely by adults of Japanese beetles and species that are much less often damaged. In turf,

Japanese beetle larvae may be controlled (at least in part) by using commercial preparations of

"milky disease" bacteria (Bacillus lentimorbus and Bacillus popilliae); these pathogens are

formulated and sold as microbial insecticides. Milky disease is NOT effective against the larvae of

the masked chafers.

Japanese beetle life cycle (University of Kentucky).

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Other scarab beetle larvae (white grubs) can also be pests of lawns and turf. Briefly review the

information on these species provided in the Handbook of Turfgrass Insect Pests displayed at this

station.

References:

Brandenburg, R.L., and M.G. Villani. 1995. Handbook of Turfgrass Insect Pests.

Entomological society of America, Lanham, MD.

Shetlar, D., and J. Andon. 2012. Identification of White Grubs in Turfgrass.

http://ohioline.osu.edu/hyg-fact/2000/pdf/2510.pdf

Townsend, L. Undated. Japanese Beetles.

http://www.ca.uky.edu/entomology/entfacts/entfactpdf/ef409.pdf

13. Sod webworms.

Left: Sod webworm adult (North Carolina State University). Right: Sod webworm larva (University of Florida).

Several species of sod webworms are native to North America and common in the eastern United

States. Larvae are light green to gray or brown, with light brown to black head capsules. They

range from 0.6 to 1.1 inch long (16-28 mm) when mature. Moths are about ½- to 3/4- inch long,

with a wing span of 0.6 to 1.4 inches (15-35 mm), and their labial palps project forward to give a

snout-like appearance. They are slender, and when at rest their wings project back and are slightly

wrapped around the body, giving them a tube-like appearance. They fly short distances in a zigzag

pattern. Larvae overwinter, pupate and emerge as moths in spring, and 2 to 3 generations develop

each season in Illinois. Egg-to-adult generation time is about 6 weeks on average.

Larvae of the sod webworms feed on grass leaves, sometimes cutting grass blades and dragging

them into the tunnels that the larvae make in thatch. Damage is usually greatest in the late summer

and early fall, when populations are highest and grass may be stressed by heat and drought. To

sample for webworms, scouts may use a "flushing agent" -- a solution of pyrethrins or liquid soap;

the Illinois Home, Yard, and Garden Pest Guide recommends control if infestations exceed 2 per

square foot. Birds often eat webworm larvae.

Reference:

Heller, P. 2007. Sod Webworms in Home Lawns.

http://ento.psu.edu/extension/factsheets/sod-webworms-lawns

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What sampling methods and thresholds are recommended in the Penn State reference on sod

webworms? Your answer should include mention of a flushing or disclosing agent … what does

such an agent do?

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

14. Honey bees, bumble bees, carpenter bees, and sweat bees

A bumble bee, Bombus sp. (University of Missouri).

Reference:

Wright, R., P. Mulder, and H. Reed. Honey Bees, Bumble Bees, Carpenter Bees, and Sweat

Bees. Oklahoma State University.

http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-2292/EPP-

7317web%20color.pdf Bumble bees of Illinois: http://beespotter.mste.uiuc.edu/topics/key/illinoisfieldguide.html .

Colony Collapse Disorder: A Descriptive Study.

http://www.plosone.org/article/info:doi/10.1371/journal.pone.0006481.

Describe the differences – in appearance and life history – between bumble bees and carpenter

bees.

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15. Yellow jackets and the bald-faced hornet.

German yellowjacket, University of Wisconsin.

Baldfaced hornet. R. Bessin, University of Kentucky.

References:

Yellowjackets. http://en.wikipedia.org/wiki/Yellow_jacket.

Oswalt, D., E. Benson, and P. Zungoli. 2003. Baldfaced hornets.

http://www.clemson.edu/cafls/departments/esps/factsheets/medvet/baldfaced_hornets_mv1

5.html Hahn, J., P. Pelletteri, and D. Lewis. 1996. Wasp and bee control.

http://www.extension.umn.edu/distribution/horticulture/DG3732.html

Describe the life history of bald-faced hornets.

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Study Questions:

What orders are represented as pests in the stations presented in this lab?

Which of the pests covered in this lab or introduced / exotic?

Which of the pests covered in this lab do not overwinter here?

In what portions of the year are eastern tent caterpillars, fall webworms, and bagworms

actively feeding on trees and shrubs?

What name is given to the mobile first-instar of scales (before they “settle” and become

sedentary)?

What taxa (orders and or families) are common gall inducers?

How can you distinguish annual white grubs, perennial white grubs, and Japanese beetle

larvae from each other?

Write a paragraph that tells the similarities and differences (morphological, behavioral,

and/or ecological) in honey bees, bumble bees, carpenter bees, yellow jackets, and

baldfaced hornets.

Which insects covered in this lab are vectors of pathogens that cause plant diseases? (And

what is a vector?)