Manual E, Chapter 3: Insects and their relatives

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Manual E, Chapter 3Insects and their relatives
Dr. Vera Krischik, Department of Entomology,
University of Minnesota

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Manual E, Chapter 3Insects and their relatives
Learning objectives

• Why insects are beneficial
• Pest damage
• Understand basic insect biology
• Common insect pests attacking turf/ornamentals
• Continue professional development

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Manual E, Chapter 3Insects and their relatives
Terms to know
vector Insects that transmit disease causing microbes from plant to plant
arthropod Scientific name for all insects and relatives
entomologist Scientist who studies insects and mites
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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects and their relatives
Beneficial insects

• BC Beneficial insects
• ladybird beetles
• lacewings
• Trichogramma parasitic wasps
• Sold by companies for augmentation

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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects and their relatives
Major insect orders Class Insecta

• Orthoptera
• Incomplete metamorphosis, nymphs resemble adults
• Chewing mouthparts
• Grasshoppers, crickets, katydids

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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects and their relatives
Ornamental plant pests Leaf-chewing

• Removes leaf area.
• Cutworm caterpillars
• Sawflies
• Elm leaf beetle
• Birch leafminer
• Cankerwoms
• Casebearers
• Webworms
• Tent caterpillars

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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects 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

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Ornamental plant pests Leaf-chewing
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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects 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

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Sawflies
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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects 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

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Ornamental plant pests Leaf-chewing
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Manual E, Chapter 3Insects and their relatives
Ornamental plant pests Leaf-chewing

• Common name Elm leaf beetle, two generations
• HostsAll 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

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Manual E, Chapter 3Insects 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

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Ornamental plant pests Leaf-chewing
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Manual E, Chapter 3Insects 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.

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Manual E, Chapter 3Insects 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

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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

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Ornamental plant pests Sucking insects and
mites
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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects 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

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Ornamental plant pests Sucking insects and
mites
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Manual E, Chapter 3Insects 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
• AdultsSmall 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

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Manual E, Chapter 3Insects 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
• AdultsSmall 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

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Manual E, Chapter 3Insects and their relatives
Ornamental plant pests Sucking insects and mites

• Feeding Sucking mouthpartssuck 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

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Ornamental plant pests Sucking insects and mites
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Manual E, Chapter 3Insects 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.

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Manual E, Chapter 3Insects 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

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Ornamental plant pests Sucking insects and mites
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Manual E, Chapter 3Insects 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
• AdultsOval green, brown 1/16 to 1/4 in ash
  plant bug (pale brown w/ yellow markings),
  honeylocust plant bug (pale green)
• Overwinter Eggs

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Manual E, Chapter 3Insects 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.
• ControlHoneylocust in sun/ yellow leaf cultivars
  more more attract to honeylocust plant bug. Spray
  week after bud break.
• Pesticides Acephate, carbaryl, malathion, soap

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Ornamental plant pests Sucking insects and mites
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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects and their relatives
Ornamental plant pests Sucking insects and mites

• Feeding Remove sap
• DamageStresses 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.

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Manual E, Chapter 3Insects 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.

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Ornamental plant pests Shoot, stem, trunk borers
iris borer
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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects and their relatives
Ornamental plant pests Shoot, stem, trunk borers

• Feeding Larvae feed on blade, then rhizome
• DamageBrown water soaked leaves. Rotting of the
  rhizome
• Control Spray leaves in early spring
• Pesticides Dimethoate (Cygon)

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Ornamental plant pests Shoot, stem, trunk borers
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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects 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

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Ornamental plant pests Gall-forming insects
/mites
gall-formers
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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects 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

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Ornamental plant pests Root-feeding insects
black vine weevil
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Manual E, Chapter 3Insects 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.

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Manual E, Chapter 3Insects 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

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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
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Ornamental plant pests Turf/ Root-feeding insects
May, June beetles root- feeders
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Ornamental plant pests Turf/ Root-feeding insects
May, June beetles root- feeders
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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects 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

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Ornamental plant pests Leaf-chewing insects
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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects 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

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Ornamental plant pests Turf / Leaf-sucking
insects
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Manual E, Chapter 3Insects 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
• AdultsSmall 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

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Manual E, Chapter 3Insects and their relatives
Ornamental plant pests Turf / Leaf-sucking
insects

• Feeding Sucking mouthpartssuck 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

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Ornamental plant pests Turf / Leaf-sucking
insects
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Manual E, Chapter 3Insects 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

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Manual E, Chapter 3Insects and their relatives
Ornamental plant pests Turf / Leaf-sucking
insects

• Feeding Adults and nymphs suck juices
• and inject toxins
• Damagebrowning blades feed along margin of dead
  and green grass
• Control
• Pesticides nematodes Steinernema carpocapsae,
  Beauveria bassiana fungus, insecticdal soaps
• Biological control Bigeyed bugs

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Ornamental plant pests Turf / Leaf-chewing
insects
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Manual E, Chapter 3Insects and their relatives
Ornamental plant pests Turf / Leaf-chewing
insects

• Common name billbug
• Hosts Turf grass
• LarvaeLegless, chew blades, then make nest in
  crown.
• Adults Dark long snout, walk on edges of hard
  surfaces in spring
• Overwinter Adults

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Manual E, Chapter 3Insects 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

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Ornamental plant pests Turf / Leaf-sucking
insects
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Manual E, Chapter 3Insects 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