Manual E, Chapter 3:
Insects and their relatives
Dr. Vera Krischik,
Department of
Entomology,
University of Minnesota
Manual E, Chapter 3:
Insects and their relatives
Learning objectives
• Why insects are beneficial
• Pest damage
• Understand basic insect biology
• Common insect pests attacking
turf/ornamentals
• Continue professional development
Manual E, Chapter 3:
Insects and their relatives
Terms to know
vector
arthropod
entomologist
Insects that transmit
disease causing
microbes from plant
to plant
Scientific name for all
insects and relatives
Scientist who studies
insects and mites
Manual E, Chapter 3:
Insects and their relatives
Introduction
• Not all insects pests
• 1,000,000 species/ total 2 million
• 10,000 insects considered pests
• Must know the difference between the two
Manual E, Chapter 3:
Insects and their relatives
Beneficial insects
•BC Beneficial insects
ladybird beetles
lacewings
Trichogramma parasitic wasps
• Sold by companies for augmentation
Manual E, Chapter 3:
Insects and their relatives
Damage caused by insects
• Chewing on leaves, fruits, seeds, roots
• Tunneling or living in stems, leaves, roots
• Sucking plant juices from leaves, stems, roots,
fruits, flowers
• Causing galls and other malformations on
plants
• Transmitting plant disease
Manual E, Chapter 3:
Insects and their relatives
The biology of insects: form and function
• Arthropods, jointed legs
• Invertebrates, no backbone, segmented
• Class Insects; Class Arachnida
• Wings: 2pairs, some orders 1, 0 wings
• Head with eyes, antennae, mouthparts
Manual E, Chapter 3:
Insects and their relatives
The biology of insects: form and function
• Insects chewing mouthparts:
Grasshoppers, beetles, caterpillars
• Insects piercing-sucking mouthparts:
siphon-like sucking;
needle-like penetrating issue
bugs, aphids, scales, leafhoppers, thrips
mosquitoes, lice, arachnids,ticks
Manual E, Chapter 3:
Insects and their relatives
The biology of insects: insect development
• Insect development: change plant
tissue into
insect biomass
• Incomplete metamorphosis:
egg, nymph, adults
examples: grasshoppers, true bugs, aphids,
leafhoppers
•Complete metamorphosis:
Egg, larvae (caterpillars, grubs, maggots),
pupae, adult
exp: beetle, moths, butterflies, flies, bees, ants
Manual E, Chapter 3:
Insects and their relatives
Major insect orders: Class Insecta
Orthoptera
•
•
Incomplete metamorphosis, nymphs resemble
adults
Chewing mouthparts
•
Grasshoppers, crickets, katydids
Manual E, Chapter 3:
Insects and their relatives
Major insect orders: Class Insecta
Hemiptera, true bugs
• Incomplete metamorphosis: nymphs resemble
adults; egg, nymph, adult
•Piercing-Sucking mouthparts
• Bed bugs, plant bugs, damsel bugs, assassin bugs
• Inject toxins into hosts, wilting
• Transmit diseases
Manual E, Chapter 3:
Insects and their relatives
Major insect orders: Class Insecta
Homoptera, aphids, scales, winged/wingless
• Incomplete metamorphosis: nymphs resemble
adults; egg, nymph, adult
• Piercing-sucking mouthparts
• Aphids, psyllids, scales, mealybugs, leafhoppers,
spittlebugs
• Suck juices, wilting,
• Transmit diseases
Manual E, Chapter 3:
Insects and their relatives
Major insect orders: Class Insecta
Thysanoptera, thrips, winged/wingless
• Incomplete metamorphosis: nymphs resemble
adults; egg, nymph, adult
• Piercing- sucking mouthparts
• Aphids, psyllids, scales, mealybugs, leafhoppers,
apittlebugs
• Suck juices, wilting
• Transmit diseases
Manual E, Chapter 3:
Insects and their relatives
Major insect orders: Class Insecta
Coleoptera, beetles, weevils
• Complete metamorphosis: egg, larvae, pupae,
adult
• Chewing mouthparts in larvae and adults
• Adults with first pair of wings hardened into elytra
• Range from pinhead size to several inches long
• Grubs in turf, lady beetles, leaf beetles, borers
Manual E, Chapter 3:
Insects and their relatives
Major insect orders: Class Insecta
Lepidoptera, moths, butterflies
• Complete metamorphosis: egg, larvae, pupae,
adult
• Chewing mouthparts in larvae; adults no
mouthparts or coiled for nectar feeding
• Two pairs of wings
• Moth antennae feathery; butterfly clubbed
• Moth nocturnal; butterfly diurnal
Manual E, Chapter 3:
Insects and their relatives
Major insect orders: Class Insecta
Diptera, flies
• Complete metamorphosis: egg, larvae, pupae,
adult
• Chewing mouthparts in larvae; adults
piercing/sucking/lapping/biting mouthparts
• One wings; second pair halteres, club-like organs
• Flies, mosquitoes, gnats, midges
• Transmit disease, as soft rot
Manual E, Chapter 3:
Insects and their relatives
Major insect orders: Class Insecta
Arachnida: Acarina, mites
• Four pairs of legs
• Chelicerae, fangs/sucking mouthparts that inject
toxins into tissue
• No wings, tiny
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: 26 artificial groups
in five categories
• Leaf-chewing
• Sucking insects and mites
• Stem , shoot, and trunk borers
• Gall-forming insects and mites
• Root-feeding insects
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Leaf-chewing
• Removes leaf area.
• Cutworm caterpillars
• Sawflies
• Elm leaf beetle
• Birch leafminer
• Cankerwoms
• Casebearers
• Webworms
• Tent caterpillars
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Leaf-chewing
• Common name: Cutworms
• Hosts: Grass and seedlings
• Larvae: Fat, thick, curl when touched, 1-2 inches
•Adults:
Dull colored moths
•Overwinter: Larvae or pupae
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Leaf-chewing
• No. of generations: One
• Feeding: Feed, lay eggs
at night
• Damage: Cutting off stems at soil surface
• Control: Cut grass in early morning to kill foraging
larvae
Ornamental plant pests: Leaf-chewing
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Leaf-chewing
• Common name: Cankerworms, inchworms
Two species: Fall cankerworm lays eggs in fall on
twigs and spring cankerworm lays eggs in spring on
bark
• Hosts: Elm, apple, basswood, oak, boxelder, ash,
maple
•Larvae: Inch along, balloon on silk
•Adults: Gray brown colored moths
•Overwinter: Eggs or pupae
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Leaf-chewing
• No of generations: One
• Feeding: On leaves
• Damage: Holes in buds and leaves
• Control: Early in spring when noticed
Sawflies
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Leaf-chewing
• Common name: Sawflies, caterpillar-like
• Hosts: Conifers, rose, mountain ash, pear
•Larvae: More than 6 prolegs (caterpillars have 2-5
legs)
•Adults: Look like flies, but antennae are plumose;
two pairs of wings; eyes not like flies
•Overwinter: Pupae in cocoons in soil, eggs
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Leaf-chewing
• No of generations: One/several depends species
• Feeding: Feed in groups
• Damage: Removes terminals or basal ends of
shoos depending on the species in conifers; entire
shoot in Rose family
• Control: Early in spring when noticed before
defoliation is too high.
• Pesticides: Not Bacillus thuringiensis var. kurstaki
(BT), Dipel, Thuricide; Orthene, Malathion, Sevin
Ornamental plant pests: Leaf-chewing
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Leaf-chewing
• Common name: Elm leaf beetle, two generations
• Hosts:All species of elms
• Larvae: Small yellow and black stripes.1/2 in
• Adults: Brownish yellow, 1/4 in
• Pupae: On top of mulch, soil under the tree
• Overwinter: Adults in houses, under bark
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Leaf-chewing
•No of generations: Two
• Feeding: Larvae feed on underside of leaf,
skeletonizing; females feed for one month laying
eggs every few days
• Damage:
Larvae skeletonizing; adults chew holes
• Control: Time to spray in May for gen one and July
for gen two
Ornamental plant pests: Leaf-chewing
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Leaf-chewing
• Common name: Birch leaf miner
• Hosts: Gray, Paper; European white birch
• Larvae: In mines, inside the leaves, blotch not
serpentine mines
• Adults: Look like flies, but antennae are plumose;
two pairs of wings; eyes not like flies
• Overwinter: In soil as pupae.
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Leaf-chewing
• No of generations: Two
• Feeding: Only larvae in mines
• Damage: Brown blotch mines In dry years or heavy
infestation can kill trees
• Control: Time to spray in May for ggemone and
mid-June for gen two, only if tree is severely
defoliated. Degree day is 310 days (around May 15)
for gen 1
• Pesticides: Dimethoate or acephate are systemic
insecticides, not residual. Metasystox-R2 in soil with
Kiornitz injection system
Ornamental plant pests: Sucking insects and mites
•Sucking insects remove
pholem or xylem from
the plant, causing wilting,
brown discoloration,
and possible leaf death.
Sooty mold often grows on
the liquid feces,
causing loss
of photosynthate.
• Spider mite
• Mites
• Leafhoppers
• Plant bugs
• Ash/ honeylocust plant bug
Ornamental plant pests: Sucking insects and mites
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Sucking insects and mites
• Common name: Spider mites, galls, free-roaming
• Hosts: Many plants
• Larvae: Six legs
• Adults: Tiny round relatives to insects; red, green,
brown, yellow, w/ or w/o spots. Eight legs, two body
regions. Most destructive in hot, dry weather
• Overwinter: Eggs or adults
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Sucking insects and mites
• Feeding: Use chelicerae or
fangs to inject toxins
into leaves.
• Damage: Discoloration, distortion, webbing, galls,
russeting
• Control: Use a miticide, spray plants to dislodge
mites.
• Biological control: Many natural enemies such as
green lacewings, ladybugs, damsel bugs
Ornamental plant pests: Sucking insects and mites
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Sucking insects and mites
• Common name: Aphids, approx 50 species
• Hosts: Many plants
• Nymphs: Young resemble adults, except for size
• Adults:Small 1/16 to 1/18 in; females give birth to
live young, wingless; wings produce in fall and when
food quality decreases. Long antennae, tubercles on
the rear of abdomen.
• Overwinter: Eggs or adults
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Sucking insects and mites
• Common name: Aphids, approx 50 species
• Hosts: Many plants
• Nymphs: Young resemble adults, except for size
• Adults:Small 1/16 to 1/18 in; females give birth to
live young, wingless; wings produce in fall and when
food quality decreases. Long antennae, tubercles on
the rear of abdomen.
• Overwinter: Eggs or adults
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Sucking insects and mites
• Feeding: Sucking mouthparts;suck sap on
underside of leaf, leaf curl around them. Suck juices
from leaves, stems, buds
• Damage: Produce honeydew on which sooty mold
grows. Cause plants to stunt, do poorly. On bark
aphids do little damage.
• Disease: Carry pathogens, virus
• Control: Spray water
• Pesticides: Orthene, Cygon, Malathion, insecticidal
soap
• Biological control: Green lacewings, ladybugs,
damsel bugs, syrphid flies
Ornamental plant pests: Sucking insects and mites
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Sucking insects and mites
• Common name: Leafhopper
• Hosts: Maple, sycamore, hawthorn, azalea
• Nymphs: Similar to adult without wings
• Adults: Small green, wedge shaped, 1/4 to 1/3 in;
wings roof-like over head; numerous,rise like a
cloud of dust
• Overwinter: Eggs or adults.
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Sucking insects and mites
• Feeding: Suck juices from leaves, stems, buds
• Damage: Irregular patches where leaves are
bleached. Can be common in turf.
• Control: Not usual, spray foliage with insecticidal
soap
Ornamental plant pests: Sucking insects and mites
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Sucking insects and mites
• Common name: Plant bugs; ash plant bug,
honeylocust plant bug
• Hosts: Ash, honeylocust
• Nymphs: Look like adults, wingless
• Adults:Oval green, brown 1/16 to 1/4 in ash plant
bug (pale brown w/ yellow markings), honeylocust
plant bug (pale green)
• Overwinter: Eggs
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Sucking insects and mites
• Feeding: Underside of leaves
• Damage: Brown, puncture wounds from
mouthparts; leaves run yellow or brown w/ stippling,
brown excrement on underside of leaves.
Honeylocust plant bug can damage buds and young
leaves.
•Control:Honeylocust in sun/ yellow leaf cultivars
more more attract to honeylocust plant bug. Spray
week after bud break.
•Pesticides: Acephate, carbaryl, malathion, soap
Ornamental plant pests: Sucking insects and mites
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Sucking insects and mites
• Common name: Scales
• Hosts: Many plants
• Crawlers: Small white,
yellow, orange, w/ legs.
• Adults: Lack wings, antennae, eyes; round, waxy
protective shells/covers or wool-like filaments; all
colors
• Overwinter: Eggs, immature females, adult females
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Sucking insects and mites
• Feeding: Remove sap
•Damage:Stresses plant, dieback on twigs, leaves;
Honeydew promotes black sooty mold.
•Control: Time pesticide application to when
crawlers have emerged. Dormant oils in late winter
may work on some scales.
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Shoot, stem, trunk borers
• Borers can
attack trunk, branches, roots. In
general, the adult borer emerges in the spring and
lays an egg that hatches and chew into the bark.
Larvae pupate inside the host and chew an exit hole
to emerge.
•Feeding interferes with the movement of water and
nutrients, permits the invasion of damaging
microorganisms; Plants will grow poorly, have
irregular form, die, or be easily damaged by weather.
Ornamental plant pests: Shoot, stem, trunk borers
iris borer
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Shoot, stem, trunk borers
• Common name: Iris borer
• Hosts: Iris
•Larvae: White
•Adults: Drab moth in Fall when it lays eggs on
leaves.
•Overwinter: Eggs on leaves
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Shoot, stem, trunk borers
• Feeding: Larvae feed on blade, then rhizome
• Damage:Brown water soaked leaves. Rotting of the
rhizome
• Control: Spray leaves in early spring
• Pesticides: Dimethoate (Cygon)
Ornamental plant pests: Shoot, stem, trunk borers
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Shoot, stem, trunk borers
• Common name: Bronze birch borer
• Hosts: Birch, white birch
•Larvae: White, flatheaded larvae
•Adults: Metallic wood boring beetles leave
•D-shaped exit holes in bark
•Overwinter: Larvae in trunk
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Shoot, stem, trunk borers
• Feeding:
Larva feed in cambium, but can move
into heartwood to pupate; tunnels packed with frass
• Damage: Interfer with movement of fluids; calluses
from feeding in tunnels appear as ridges on the bark
• Control: Red or river birch more resistant; Borers
prefer to lay eggs I sun, birches prefer cool
understory, not exposed sites due to shallow roots
• Pesticides: Repeated application of
chlorpyrifos(Dursban) or bendioarb (Turcam,
Dycarb) to trunk
Ornamental plant pests: Gall-forming insects /mites
gall-formers
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Gall-forming insects /mites
•
Common name: Oak cynipid gall, hackberry
nipple gall, maple spindle gall, maple velvet gall
•
Hosts: Oaks, hackberry, maple
•
Larvae: Inside galls
•
Adults: Short-lived, lay eggs
•
Overwinter: in galls
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Gall-forming insects /mites
•
Feeding: Inside gall
•
Damage: Only disfigures leaf, stem, rarely kills
•
Control: Must be before budbreak;
once gall is formed can not control
Ornamental plant pests: Root-feeding insects
black vine weevil
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Root-feeding insects
•
Common name: Black vine weevil
•
Hosts: Yews, azaleas, many plants
•
Larvae: On roots, white, plump, legless
•
Adults: Black, long snout, live 1 year
•
Overwinter: As larvae or adults in soil.
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Root-feeding insects
•
Feeding: Adults leaves, grubs roots
•
Damage: Adults notch leaves, grubs on roots,
grubs can spread disease
•
Control: Spray foliage and drench soil
Ornamental plant pests:
Turf / Leaf-chewing insects
Grubs: Birds, skunk damage, turf pulls from roots
Sod webworm: Moths flying above turf
Billbugs: Yellowing, browning
Chinch bugs, Aphids: brown patches
Ornamental plant pests: Turf/ Root-feeding insects
May, June beetles: root- feeders
Ornamental plant pests: Turf/ Root-feeding insects
May, June beetles: root- feeders
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Turf/ Root-feeding insects
•
Common name: May, June beetles
•
Hosts: Turf grasses
•
Grubs: C-shaped in soil feeding on roots
•
•
Adults: Large June beetles have 3 year life
cycle
Overwinter: Grubs in soil
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Turf/ Root-feeding insects
•
•
•
Feeding: grubs on roots; adults on Norway
maple, grapes,linden
Damage: Remove roots, leaves
Control: 2 or more grubs per sg ft Treat in
year two, treat in June, not fall as grubs
move down into the soil to overwinter
Ornamental plant pests: Leaf-chewing insects
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Turf / Leaf-chewing insects
•
Common name: Sod webworms, lawn moths
•
Hosts: Turf grass
•
•
•
Larvae: Dirty white w/ dark boxy spots; rest in
silken tunnels; glisten in dew
Adults: Narrow appearance due to folded wings,
darting flight above turf grass; two gen June,
Aug
Overwinter: Larvae in soil in tunnels
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Turf / Leaf-chewing insects
•
•
•
•
Feeding: Remove leaf blade
Damage: Small brown areas; not
common
Control: 15 worms/sg yd
Pesticides: nematodes Steinernema
carpocapsae, Beauveria bassiana
fungus, Bacillus thuringiensis var.
kurstaki Btk, insecticdal soaps
Ornamental plant pests: Turf / Leaf-sucking insects
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Turf / Leaf-sucking insects
• Common name: Greenbugs, aphids, approx 50
species
• Hosts: Many plants
• Nymphs: Young resemble adults, except for size
•Adults:Small 1/16 to 1/18 in; females give birth to
live young, wingless; wings produce in fall and when
food quality decreases. Long antennae, tubercles on
the rear of abdomen.
• Overwinter: Eggs or adults
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Turf / Leaf-sucking insects
• Feeding: Sucking mouthparts;suck sap on
underside of leaf, leaf curl around them. Suck juices
from leaves, stems, buds
• Damage: Produce honeydew on which sooty mold
grows. Cause plants to stunt, do poorly. On bark
aphids do little damage.
• Disease: Carry pathogens, virus
• Control: Spray water
• Pesticides: Orthene, Cygon, Malathion, insecticidal
soap
• Biological control: Green lacewings, ladybugs,
damsel bugs, syrphid flies
Ornamental plant pests: Turf / Leaf-sucking insects
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Turf / Leaf-sucking insects
•
•
•
•
•
Common name: Chinch bug
Hosts: Turf grass
Nymphs: Look like adults w/o wings; red
become dark as mature
Adults: Head narrower than shoulders;
light colored forewings with black
triangle.Females lay 200 eggs in 3 to 5
weeks
OOver winter Adults
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Turf / Leaf-sucking insects
•
Feeding: Adults and nymphs suck juices
and inject toxins
•
•
•
•
Damage:browning blades; feed along margin
of dead and green grass
Control:
Pesticides: nematodes Steinernema
carpocapsae, Beauveria bassiana fungus,
insecticdal soaps
Biological control: Bigeyed bugs
Ornamental plant pests: Turf / Leaf-chewing insects
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Turf / Leaf-chewing insects
•
Common name: billbug
•
Hosts: Turf grass
•
•
•
Larvae:Legless, chew blades, then make nest in
crown.
Adults: Dark long snout, walk on edges of hard
surfaces in spring
Overwinter: Adults
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Turf / Leaf-chewing insects
•
Feeding: Adults and larvae chew blades
•
Damage: Brown, irregular shaped areas in
lawn. 10 larvae/sg ft need control
•
Control: May adults; larvae when small
Ornamental plant pests: Turf / Leaf-sucking insects
Manual E, Chapter 3:
Insects and their relatives
Ornamental plant pests: Turf / Leaf-chewing insects
•
•
False chinch bug: Does not have black triangle
in wings, head is same size as thorax; do not
need to control.
Big-eyed bugs: Large eyes, head same size as
thorax and are predators
•
Night Crawlers: Do not control
•
Ants: Do not control