entomology for master gardeners...complete metamorphosis • the four distinct stages: egg, larva...
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Entomology For Master Gardeners
Jeff Schalau (Adapted from Dr. Mike Wagner,Regents Professor-Emeritus,NAU School of Forestry)Agent, Ag. & Nat. Res.University of Arizona Cooperative Extension,Yavapai County
Outline of Topics Covered• 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 component of current fauna• Attack all stages of all plant species• Damage equals harvest• Beneficial aspects
Beneficial Aspects• Pollination (honey/bumble/mason bees) • Predators/Parasites• Human food• Biological control agents• Nutrient recycling• Insect products: honey, wax, shellac, dye• Conservation biology • Art and literature• Ecotourism- butterfly farms/exhibits
Orchard Mason Bee• Hymenoptera: Megachilidae
-thick jaw • Osmia lignaria
Mason Bees• Solitary/Gregarious bee• Blue/black color• Non-aggressive; rarely stings • Native to U.S; east/west species • Better pollinator than honey bees
-scopa vs pollen basket • Commercial use
-almonds, walnuts, alfalfa, fruit trees
Mason Bee Life Cycle - 1• Overwinters as adult in tunnel/ tube • Male emerges first
-when high temp is above 55F for 4 days• Female emerges 3-15 days later • Mating begins as soon as female emerges• Female lays 6 nest holes; 6 cells each• Female dies immediately after 6th cell
Mason Bee Life Cycle - 2• Eggs hatch in 3-4 days • Larvae feed for 28-29 days• Larvae spins cocoon (pupae) • Rest for 30 days • Pupal stage lasts 21 days • Egg to adult is about 3 months
Mason Bee Propagation • Nest boxes: holes in wood/nest tubes• Wooden block 6” deep
-holes 5/16” diameter-spaced ¾” apart
• Place facing east under eave• Harvest tubes in fall; keep in fridge at 38F
Mason Bee Taj Mahal
Mason Bee Management • Short period of pollination in spring • Remove overwintering bees in fall • Use staggered removal from cold for longer
pollination period • Protect from woodpeckers, ants, diseases,
parasites, and predators • Use liners to allow winter storage
Butterfly Exhibits(Sertoma Butterfly House, Sioux Falls, SD)
Characteristics of Insects • Arthropods: exoskeleton, jointed
appendages• Adult Insects:
• Head, thorax, abdomen• 1 pair antennae• 3 pair legs• 2 pair of wings• Bilateral symmetry
ArthropodsPhylum Arthropoda: includes trilobites, horseshoe crabs, spiders, mites, sowbugs, crustaceans, millipedes, and centipedes.
Prolegs
Thoracic legs
Thoracic legs
Insects are all in the Class HexopodaInsects are all in the Class Hexopoda1. The head is a sensory organ with paired
appendages (antennae and eyes) and mouthparts
2. The thorax is mainly involved in motility (walking and flying)
3. The abdomen has reproductive and digestive functions
Insect Growth and Development• Metamorphosis • Shed exoskeleton (molting)• Stages
• Egg• Larva/nymph• Pupa• Adult
• Instars
Metamorphosis: Simple
Wing pads
Wings
Squash bugs
Metamorphosis: Complete
Metamorphosis
Insect Growth and Development• Gradual (aka Simple):
• Egg-nymph-adult• Nymph similar to adult• Ex. Aphids, scales, grasshoppers
• Complete (aka Complex):• Egg-larva-pupa-adult• Larva does damage• Stages occur in different habitats• Ex. Beetles, butterflies, flies
Insect Feeding/Mouthparts• Chewing
• Hard mandibles• Holes, tunnels, partially eaten leaves
• Sucking• Straw (stylet), probosis• Curling, stunting, mottling, galls• Phytotoxic necrosis
Four Types of Mouth Parts
Piercing/sucking
Straw
Chewing Mandibles
Piercing/sopping
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 levels: Order and Family• Basis for classification
• Mouthparts• Type of wings• Type of metamorphosis• Genetics has also taken a role in
classification
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
Common Insect Orders (cont.)• Lepidoptera: moths, butterflies• Neuroptera: lacewings, antlions• Odonata: dragonflies, damselflies• Orthoptera: grasshoppers, crickets,
mantids, cockroaches • Siphonaptera: fleas• Thysanoptera: thrips• Thysanura: siverfish, firebrats
Coleoptera: beetles, weevils
Attributes: 400,000 species, hard front wings, beneficial and pest species, adults and larvae may feed on same host
Complete metamorphosis
Chewing
Dermaptera: earwigs
Attributes: front wings thickened, pest or beneficial (aphid predator), nocturnal, hide during the day
Gradual metamorphosis
Chewing
Diptera: flies, mosquitoes
Attributes: larvae legless, adults soft bodied, compound eye, one pair of wings, haltere, vector of human diseases (Zika, Malaria, Yellow Fever) , pest and beneficial
Complete metamorphosis
Larvae: chewing/hooksAdult: sponging, piercing
Hemiptera: true bugs
Attributes: nymphs resemble adults, many plant feeding pests, triangle on back, some predators, some disease vectors (Chagas disease)
Gradual metamorphosis
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 metamorphosis
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 have social behavior
Complete metamorphosis
Chewing
Isoptera: termites
Attributes: soft bodied insects, winged or wingless, colonies occur in ground or in wood, drywood and subterranean termites, caste system, social
Gradual metamorphosis
Chewing
Lepidoptera: moths, butterflies
Attributes: caterpillars, adults have two pairs of scaled wings, many defoliators, adults feed on nectar, adults pollinate, basis for ecotourism
Complete metamorphosis
Larvae: chewing Adults: sucking
Monarch Life Stages
Monarch Life• Butterflies (and moths) undergo
complete metamorphosis• The four distinct stages: egg, larva
(caterpillar), pupa, and adult• The development from egg to adult is
completed in about 30 days
Stage 1: egg• Monarchs lay 100-300 eggs • Often on the bottom of a milkweed
leaf for protection• The eggs hatch about four days after
they are laid
Stage 2: larva (caterpillar)• Eggs hatch into larvae (0-14 days)• They first eat their eggshell, then start
munching away on plants for energy to grow
• Caterpillars sequester cardiac glycosides from milkweed for defense against predation
• When the larva outgrows its skin, it sheds it and grows a new skin
Stage 3: pupa (chrysalis)• Transformation from larva to an adult
butterfly• Camouflaged to protect against
predators• Has no eyes, antennae or legs • Mouthparts change from chewing in
the caterpillar to straw-like tongue that the adult butterfly will need to sip nectar and it grows wings. All in just about two weeks!
Stage 4: Adult Monarch• Summer generations live from 2-5 weeks• Late summer and early fall generations
migrate to their central Mexico (Easterns) or California (Westerns)
• They return to the north when the colder weather ends to reproduce. These adults can live up to eight or nine months
Neuroptera: lacewings, antlions
Attributes: adults have 2 pairs of membranous wings, wings held roof-like, many species are predators
Complete metamorphosis
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 metamorphosis
Chewing
Siphonaptera: fleas
Attributes: wingless insects, live as ectoparasites on birds and mammals, body is laterally flattened, often jumping, important vector of human disease (Plague, Hantavirus, and typhus)
Complete metamorphosis
Sucking
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 metamorphosis
Sucking
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• Take notes• Formulate hypothesis• Important? Seek professional advice
Pest Management• Integrated Pest Management• Legislative Control• Physical/Mechanical Control• Cultural Control• Genetic Resistance • Biological Control• Chemical Control
Integrated Pest Management (IPM)• Integrate all approaches to manage
pest• Pest ID• Detection, monitoring models• Know insect biology• Ecologically sound
Legislative Management• Quarantine• State regulation- noxious weeds• Public education critical
Physical Management• Insect removal/habitat destruction• Sanitation/salvage• Firewood in direct sun• Physical barriers- cutworms• Mass trapping• Trap trees
Cultural Management• Crop rotation• Green manure fallow• Farmscaping• Genetic resistance
• Conventional resistant varieties• GMO’s
Row Cover: Excludes pest/ moderates temperature
Row Cover: Excludes pest/ moderates temperature
Physical barriers for cutworms
Farmscaping• Whole farm approach to improve
natural control of agricultural pests• Includes:
-Inter-planting vs companion planting-Support population of beneficial insects, biological control, habitat for natural enemies, nectar for pollinators
Genetic Resistance• Pest impact increasing: climate change
complications/ globalization/ exotic pests • Genetic manipulation very powerful• Work with conventional genetic methods• Possible to eliminate major human disease
(Zika, Malaria)• Cost effective/time efficient • Deployment of technology is key
Pest impact increasing: climate change complications/ globalization/ exotic pests Genetic manipulation very powerfulWork with conventional genetic methodsPossible to eliminate major human disease (Zika, Malaria)Cost effective/ time efficient Deployment of technology is key
GMO Risks• Genetic contamination of natural/ non-
target populations• Evolution of super weeds • Non-target effects (Bacillus thuringiensis in
pollen) • All options have consequences
Biological Control/Management• Ecologically best strategy• Life history knowledge critical• Bio control agents
• Vertebrate predators• Invertebrate predators• Invertebrate parasites• Pathogenic microorganisms
• Ex. Virus, bacteria (Bt), fungi, protozoa, nematodes
Chemical Management• 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• Learn to tolerate plant damage• Apply the least effort to reduce
economic threshold• Try to target pest management efforts• Share the planet!
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