Bug Basics

Peter WarrenCounty Extension Director

Urban Horticulture Extension AgentPima County Cooperative Extension

University of Arizona

Overview

The Big Picture Identification Diagnosing Plant Damage Identification Tools Common & Invasive Pests Benefits

From “Evolution of the Insects”(Grimaldi & Engel 2005)

Identifying Arthropods

Animals Segmented body Exoskeleton Paired jointed

appendages Bilateral symmetry

Arthropod Groups

Crustacea Diplopoda Chilopoda Symphylans Xiphosura Arachnida Insecta

>> Water fleas, shrimps, lobsters, crayfish, crabs, sowbugs (pillbugs)>> Millipedes

>> Centipedes

>> Symphyla

>> Horseshoe Crabs

>> spiders, scorpions, harvestmen, mites, ticks

>> insects

Insect Classification

Kingdom - Animal

Phylum - Arthropoda

Class - Insecta

Order - Hemiptera

Family - Pentatomidae

Genus - Nezara

Species - viridula

Author - Linnaeus

Insect Orders

Approximately 31 Orders Divided primarily on

– type of metamorphosis – structure of wings– structure of mouthparts

Mantophasmatodea

Insect Development

Metamorphosis– Meta = change– Morph = form

Two types of Metamorphosis– Simple = gradual change– Complete = profound change

Molting Evolutionarily advanced Orders

use complete metamorphosis

Immature versus Adult

Many wormlike Number of legs varies Most soft and fleshy No wings Most slow moving Examples

– Caterpillars, Maggots, Grubs

Three body segments Six legs Most crunchy Most have wings Most fast moving Examples

– Butterflies, Flies, Beetles

Key Immature Characteristics Where are they found? What are they eating? Do they have legs? If so, how many? Coloration?

Meet the Beetles

Key Adult Characteristics Exoskeleton

– protection– support

Head– antennae– eyes– mouthparts

Thorax– legs– wings

Abdomen– digestion– respiration

Abdomen

Internal organs– For reproduction, digestion,

circulation, and respiration External structures

– Cerci: feeler-like appendages

– Ovipositor: egg laying device, sometimes modified for defense

– Spiracles: openings for respiration

Thorax

Wings

Present only in the adult stage (one exception)

At most two pairs found Many variations in form

Wing Variations

Coleoptera (Beetles) Elytra -- hard, sclerotized front wings that

serve as protective covers for membranous hind wings

Wing Variations

Hemiptera: (True Bugs) Hemelytra -- front wings that are leathery or

parchment-like at the base and membranous near the tip

Wing Variations

Orthoptera, Blattodea, and Mantodea (grasshoppers, cockroaches, & mantids)

Tegmina -- front wings that are completely leathery or parchment-like in texture

Wing Variations

Diptera (flies) Halteres -- small, club-like hind wings that

serve as gyroscopic stabilizers during flight

Wing Variations

Thysanoptera (thrips) Fringed wings -- slender front and hind wings

with long fringes of hair

Wing Variations

Lepidoptera (butterflies & moths) Scaly wings -- front and hind wings covered

with flattened setae (scales)

Wing Variations

Many Orders (dragonflies, bees, etc.) Membranous wings -- front and hind wings

thin and more or less transparent

Wing Venation

Costa (C) Subcosta (Sc) Radius (R) Media (M) Cubitus (Cu) Anal veins

(A1, A2, A3)

Times fun when your having flies

Mouthparts

Chewing Piercing/Sucking

Sponging/Lapping Siphoning/Sucking

Herbivorous & predacious bugs and mosquitoes

Mandibles and maxillae are formed into stylets enclosed by the labium

Once the stylets penetrate, a secretion is injected to dissolve tissue– act as a toxin in predacious

species– act as anticoagulant for

mosquitoes

Diagnosing Plant Damage

Chewed leaves or blossoms Discolored leaves or blossoms Distorted leaves, branches, or trunks Dieback of shoots, twigs, or branches Products of insects and mites

Types of Insect Injury

Chewing Piercing sucking Internal feeders Subterranean Egg laying Nest material Disease vector

>> beetles, caterpillars, grasshoppers, etc.

>> aphids, scale, leafhoppers, etc.

>> leaf miners, borers, caterpillars, etc.

>> wireworms, root maggots, rootworms, etc.

>> cicadas, gall insects, etc.

>> leaf cutter bees, etc.

>> aphids, leafhoppers, bees, beetles, etc.

Effective Diagnosis Recognition of symptoms

– Regular monitoring– Record keeping

Accurate identification– Close examination– Consulting experts as needed

Knowledge of pest life cycle– Identify susceptible life stages– Determine location for management

Distribution of pest population – Are there enough of them to be a problem?– Are they wide spread or spreading?

Landscape CSI

Success depends on early identification and diagnosis Clues for diagnosis

– Problem symptoms» Nuts drop early» Nuts without edible meat

– Problem signs» Worm-like critter or frass in shell» Holes in shell

– Host preference» Shagbark hickory

Resources for diagnosis– Coworkers– Reference books, internet– Extension Office

Determining Insect Pest Status

First goal: identify to Order level (such as bee, beetle, fly)– antennae, wings, mouthparts– shape, texture, size, color– life stage: egg, larva, pupa,

adult Then use other clues to

determine pest status– Host plant– Activity and/or damage

» feeding, flying, crawling, etc.

Diagnostic Tools

Sources of Information

Publications– Land-grant Universities– OMRI.org– BIRC.org

Community Availability– Survey Local Stores/Nurseries– Cooperative Extension/MGs

Dotcom Resources & Catalogs– Buyer beware– Check for products that have been

tested by reputable organizations– Ask for data and references

Components of an IPM Program Knowledge of Plants and Pests

– Potential pests and conditions likely associated Setting Goals for Protection

– Action thresholds and available control options available Site Maps

– Details the physical and environmental features Monitoring

– Weekly checks recommended Making Control Decisions

– Considering the data available Record Keeping

– Date, location, weather, activity Evaluation

Overview of IPM Options

Host resistance Biological control Chemical control Cultural control Mechanical control Do nothing

Host Resistance

Plants naturally evolve resistance to pests

Plant breeding is used to alter the process

Genetic engineering provides a new wrinkle

This must be the one with

insect resistance!

Biological Control

Predators, parasites or parasitoids, and pathogens Lower pest densities to innocuous levels and keep them there Attract beneficial insects by planting flowering nectar & pollen sources Release beneficial insects into environments where pests exist

Chemical Control

Avicides to control pest birds Bactericides to destroy bacteria Fungicides to destroy fungi Herbicides to kill weeds Insecticides to destroy insects Miticides to kill mites Molluscicides to kill snails and slugs Nematicides to kill nematodes Piscicides to control pest fish Predacides to control vertebrate pests Rodenticides to destroy rodents

Pesticide Effectiveness

Type– match chemical with

problem Time

– use chemical when most effective

Place– use chemical where most

effective

Non-target Organisms

Mammals Birds Fish Bees

Least Toxic Insecticides

Bacillus thuringiensis (Bt) for caterpillars, beetles, flies, etc. (making sure you buy the right one)

Insecticidal soap for aphid, mealybug, psyllid, spider mite, and whitefly control

Horticultural oils for sessile (or nearly so) pests such as hemlock wooly adelgid

Cultural Control

The deliberate alteration of the plant production system to reduce pest populations or avoid pest injury to plants

The key to successful IPM Three basic types

– Site selection– Soil preparation– Plant selection

Diversity

Avoid large plantings of one type– less attractive from the start– can slow the spread of pests

Include farmscaping plants if diversity is not realistic

Use native and well adapted species Use disease and insect resistant

varieties

Mechanical and Physical Control

Direct or indirect measures that either destroy pests outright or make the environment unsuitable

Removing pests– by hand, with traps

Preventing access to plants– screens, ditches, row covers

Sanitation– remove shelter, food sources, moisture,

attractive odors

Three Cardinal Rules of IPM

Know your ecosystem Scout regularly Keep good records

Invasive Insects Mostly accidental introductions

– Notable exceptions include gypsy moth– Humans are excellent vectors

Success– No natural enemies– Similar food plants– Similar climate

Management– Difficult to eradicate– Efforts to slow the spread– Always bet on the bug

brown marmorated stink bug

Emerald ash

borer

Asian Long-horned Beetle

Insects with Benefits

Pollination Commercial products Biological Pest Control Decomposition Food for other animals

$19 billion

+ $300 million

+ ???

+ ???

+ ???

> $20 billion

Encouragement

Diversity Food plants Native species Minimize insecticide use

– least toxic first– spot treat

Questions?