Entomology For Master Gardeners Mike Wagner Regents Professor-Emeritus Northern Arizona University School of Forestry

Outline of Topics  Extent and Economic Importance  Insect Growth and Development  Insect Feeding / Mouthparts  Classification and Taxonomy  Movement and Spread  Population Dynamics / Concept of Pest  Diagnosing Insect Problems  Pest Management Approaches

Extent and Economic Importance  Major form of higher life  Attack all stages of all species  Damage equals harvest  Beneficial aspects

Beneficial Aspects  Pollination  Predators / Parasites  Human food  Biological control agents  Nutrient recycling  Insect products: honey, wax, shellac, dye  Conservation biology  Art and literature  Ecotourism- butterfly farms / exhibits

Characteristicsof Insects  Arthropods: exoskeleton, jointed appendages  Adult Insects:  Head, thorax, abdomen  1pair antennae  3 pair legs  2 pair of wings

1.Head : Sensory Organ a) Paired appendages (antennae) b) Mouthparts 2. Thorax : Locomotion 3.Abdomen : Reproductive and Digestive Arthropods (Phylum Arthropoda: also include trilobites, horseshoe crabs, spiders, crustaceans, millipedes, centipedes) Insects are all in the HEXAPODA (class) Body with three distinct regions: head, thorax, and abdomen Head Thorax Abdomen

Prolegs Thoracic legs

Prolegs Thoracic legs

Insect Relatives  Spiders, mites, ticks, centipedes, millipedes, sowbugs, snails, slugs  Bugs vs. “bugs”

Insect Growth and Development  Metamorphosis  Shed exoskeleton (molting)  Stages  Egg  Larva/nymph  Pupa  Adult  Instars

Metamorphosis: Simple

 Wing pads Wings Squash bug

Metamorphosis: Complete

 Metamorphosis

Insect Growth and Development  Gradual:  Egg-nymph-adult  Nymph similar to adult  Ex. Aphids, scales, grasshoppers  Complete:  Egg-larva-pupa-adult  Larva does damage  Stages occur in different habitats  Ex. Beetles, butterflies, flies

Insect Feeding/Mouthparts  Chewing  Hard mandibles  Holes, tunnels, partial eaten leaves  Sucking  Straw (stylet), probosis  Curling, stunting, mottling, galls  Phytotoxic necrosis

 4 Types of Mouth Parts Piercing/sucking

Straw

 Mouth Parts Chewing

Piercing/ sopping

Insect Classification Kingdom Phylum Class Order Family Genus Species

Insect Classification Kingdom Phylum Class Order Family Genus Species Animal Arthropods Insecta Coleoptera Scolytidae Dendroctonus brevicomis

Insect Classification Kingdom Phylum Class Order Family Genus Species Animal Arthropods Insecta Coleoptera Scolytidae Dendroctonus brevicomis keen pretty clothes out fill guys some

Taxonomic Classification  Common level: Order and Family  Basis for classification  Mouthparts  Type of wings  Type of metamorphosis

Common Insect Orders  Coleoptera: beetles, weevils  Dermaptera: earwigs  Diptera: flies, mosquitoes, gnats, midges  Hemiptera: true bugs  Homoptera: aphids, scales, leafhoppers, cicadas, whiteflies, mealy bugs  Hymenoptera: bees, wasps, ants, sawflies  Isoptera: termites

Coleoptera: beetles, weevils Attributes: 400,000 species, hard front wings, beneficial and pest species, adults and larvae may feed on same host CompleteChewing

Dermaptera: earwigs Attributes: front wings thickened, pest or beneficial (aphid predator), nocturnal, hide during the day GradualChewing

Diptera: flies, mosquitoes Attributes: larvae legless, adults soft bodied, compound eye, one pair of wings, haltere, disease vectors, pest and beneficial Complete Larvae: chewing/hooks Adult: sponging, piercing

Hemiptera: true bugs Attributes: nymphs resemble adults, many plant feeding pests, triangle on back, some predators, some disease vectors (Chagas disease) Gradual Piercing, sucking

Homoptera: aphids, leaf hoppers, white flies, scales Attributes: small soft bodied insects, unwinged forms, attack many vegetables, multiple generations, parthenogenesis, some disease vectors (CTV), greenhouse pests Gradual Sucking

Hymenoptera: bees, wasps, ants, sawflies Attributes: legless larvae, adult stinger, two pair of membranous wings, ants with narrow waist, many species, pollinators, parasites, predators, sawflies are important defoliators, many species social Complete Chewing

Isoptera: termites Attributes: soft bodied insects, winged or wingless, colonies occur in ground or in wood, drywood and subterranean termites, caste system, social GradualChewing

Lepidoptera: moths, butterflies Attributes: caterpillars, adults have two pairs of scaled wings, many defoliators, adults feed on nectar, adults pollinate, basis for ecotourism Complete Larvae: chewing Adults: sucking

Neuroptera: lacewings, antlions Attributes: adults have 2 pairs of membranous wings, wings held rooflike, many species are predators Complete Chewing

Orthoptera: grasshoppers, crickets, mantids, cockroaches Attributes: hard bodied adult, two pair of wings, front wings are hard, adults and nymphs cause damage, moderate pests Gradual Chewing

Siphonaptera: fleas Attributes: wingless insects, live as ectoparasites on birds and mammals, body is laterally flattened, often jumping, important disease vectors, include plague and typhus CompleteSucking

Thysanoptera: thrips Attributes: adults are minute soft bodied, two pairs of long wings, many feed on plants and especially flowers, cause cosmetic damage to fruit, some disease transmission Gradual Sucking

Common Insect Orders Continued  Lepidoptera: moths, butterflies  Neuroptera: lacewings, antlions  Odonata: dragonflies, damselflies  Orthoptera: grasshoppers, crickets, mantids, cockroaches  Siphonaptera: fleas  Thysanoptera: thrips  Thysanura: siverfish, firebrats

Movement and Spread  Adults have wings & legs  Adults can migrate  Larvae have legs  Larvae can walk  Larvae can move with wind

Population Dynamics  Insects have high reproductive potential  Can migrate; move with plants  Population limited by:  Environmental resistance  Host plant resistance  “if you build it, they will come”  Exotic (non-native) insects

Concept of a Pest  Interfere with objectives  Insects play vital ecological roles  1% of insects are pests  Learn to live with damage- economic threshold

Diagnosing Insect Pest Problems  Recognize limitations  Most “sick” plants are abiotic  Identify the plant  Note the symptoms  Look for broad patterns  Within plant (leaf vs. fruit)  Across plant (spot vs. all plants)  Collect specimens

Diagnosing Insect Pest Problems Continued  Take notes  Formulate hypothesis  Important? Seek professional advice

Pest Managment  Integrated Pest Management  Legislative Control  Physical/Mechanical Control  Cultural Control  Biological Control  Chemical Control

IPM  Integrate all approaches to manage pest  Pest ID  Detection, monitoring models  Know insect biology  Ecologically sound

Legislative Control  Quarantine  State regulation- noxious weeds  Public education critical

Physical Control  Insect removal/habitat destruction  Sanitation/salvage  Firewood in direct sun  Physical barriers- cutworms  Mass trapping  Trap trees

Cultural Control  Crop rotation  Green manure fallow  Genetic resistance  Conventional resistant varieties  GMO’s

Biological Control  Ecologically best strategy  Life history knowledge critical  Classical vs. Bio. insect pest suppression  Bio control agents  Vertebrate predators  Invertebrate predators  Invertebrate parasites  Pathogenic microorganisms  Ex. Virus, bacteria (Bt), fungi, nematodes

Chemical Control  Limitations: ecological, cost, hazard  Follow label-legal document  Pay attention to pre-harvest interval  Federal regulation of residual tolerance  Pesticide applicator certification

Summary  Insects are part of natural system  Provide lots of useful functions  Apply the least effort to reduce economic threshold  Share the planet!