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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
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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
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
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
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
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
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
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
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
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
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
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