Basic Entomology for Idenfiers

Carlos E. Bográn, PhD Associate Professor & Extension Specialist [email protected]

TDA Inspector Training, 2012 Outline • Basic Entomology – What is an insect? – Biology and development – Common insect groups – Idenficaon, diagnosis What type of animal is an insect? • Insects are arthropods in the Class Hexapoda (six-legged) • Invertebrates (lack back-bone) with exoskeletons and segmented bodies • Ventral nerve cord; dorsal digesve track • Common arthropods include arachnids, crustaceans and their relaves Crustacea Malacostraca Decapoda (crabs, shrimp, lobsters) Isopoda (pillbugs, sowbugs) Hexapoda Entognatha Collembolla (springtails) Insecta Thysanura (silverfish) Odonata (damselflies, dragonflies) Orthoptera (grasshoppers, crickets) Hemiptera (bugs, aphids, scales)

Arthropoda Coleoptera (beetles, weevils) Lepidoptera (moths, buerflies) Chelicerata Arachnida Araneae (spiders)

Phylum Scorpiones (scorpions) Acari (cks, mites, chiggers) Myriapoda Chilopoda (Cenpedes) Diplopoda (Milipedes) Phylum: Mollusca Crustacea: Isopoda Myriapoda: Diplopoda

Entognatha: Collembola Myriapoda: Chilopoda Arachnida: Scorpiones Class Arachnida

• Mites, cks, spiders and scorpions • Two body regions: cephalothorax and abdomen • Four pairs of legs • Most are predators but some are pests

Insect Diversity

• Approximately 1 million species of insects have been named • Beetles (Coleoptera), flies (Diptera) and wasps & bees (Hymenoptera) are the most diverse groups • High insect diversity makes their idenficaon/ classificaon complex Taxonomic Classificaon • Insects are classified into groups called: Orders • Orders are subdivided into smaller groups known as Families, genera and species Example: Tea scale Order: Hemiptera Family: Diaspididae Genus: Fiorinia Species: theae North American Insect Orders 1. Microcoryphia (bristletails) 16. Phthiraptera (barklice) 2. Thysanura (silverfish) 17. Hemiptera (bugs, scales) 3. Ephemeroptera (mayflies) 18. Thysanoptera (thrips) 4. Odonata (dragonflies) 19. Megaloptera (dobsonflies) 5. Blaodea (cockroaches) 20. Rhaphidiopera (snakeflies) 6. Isoptera (termites) 21. Neuroptera (lacewings) 7. (mands) Mantodea 22. Strepsiptera (twisted-wings) 8. Grylloblaodea (rockcrawlers) 23. Coleoptera (beetles) 9. Dermaptera (earwigs) 24. Mecoptera (scorpionflies) 10. Plecoptera (stoneflies) 11. Orthoptera (crickets) 25. Siphonaptera (fleas) 12. Phasmida (sck insects) 26. Diptera (flies) 13. Embioptera (webspiners) 27. Trichoptera (caddisflies) 14. Zoraptera (angel insects) 28. Lepidoptera (buerflies) 15. Psocoptera (barklice) 29. Hymenoptera (bees) Insect Anatomy

• Head, thorax & abdomen • Antennae • Adults may have one or two pairs of wings • Three pairs of legs aached to thorax Insect Physiology

• Insects breath through spiracles; valves on the side of their body • Open circulatory system • Flight is accomplished by vibrang- resonang mechanism • Insects are poikilothermic: temperature changes with ambient Insect Development

• Metamorphosis • Stages may show differences in shape, diet and habitat • Highly developed insects experience complex metamorphosis Ametamorphosis

Simple, gradual metamorphosis

Complete metamorphosis Metamorphosis • Anamorphosis (young have less abdominal segments; very rare) • Ametamorphosis (ametabolous insects; connue molng aer adult stage) • Simple metamorphosis – Gradual (paurometabolous; young [nymphs] resemble wingless adults; in same habitat) – Incomplete (hemimetabolous; young [niad] acuac may not resemble adult) • Complete metamorphosis (holometabolous; pupal stage; may not be in same habitat) • Hypermetamorphosis (1st instar triangulin) Types of Larvae Grub Maggot

Scarabaeiform

Grub

Caterpillar Vermiform

Elateriform Campodeiform Eruciform Common Insect Orders

• Orthoptera: grasshoppers, crickets • Hemiptera: true bugs, scales, aphids, whiteflies • Thysanoptera: thrips • Coleoptera: beetles and weevils • Lepidoptera: moths and buerflies • Diptera: flies and mosquitoes • Hymenoptera: wasps, bees, ants Orthoptera: grasshoppers & crickets

• Outer wings leathery (tegmina), inner wings membranous and fan-shaped • All stages have chewing mouthparts • Undergo simple metamorphosis; wingless nymphs resemble adults • Enlarged hind legs for jumping Grasshoppers, Crickets and Katydids

False katydid

Tree cricket Field cricket

Rainbow grasshopper Differential grasshopper Cave cricket Hemiptera: Auchenorrhyncha and Stenorryncha; leaoppers, aphids, scales and whiteflies • So bodied insects with sucking mouthparts • Some adult forms lack wings • Undergo simple metamorphosis • Most excrete honeydew • Can transmit plant diseases Scales, Aphids, Whiteflies, Mealybugs, Leaoppers and Cicadas Wax scale

Green peach aphid Silverleaf whitefly

Cicadas

Sharpshooter Citrus mealybug Hemiptera: Heteroptera; true bugs • Outer wings thickened or leathery at base and membranous at p (hemelytra), inner wings membranous • Piercing and sucking mouthparts • Undergo simple metamorphosis • Triangular plate (scutellum) between thorax and abdomen on the back The True bugs!!

Spined soldier bug Giant water bug Azalea lacebug Water strider

Bigeyed bug Leaffooted bug Thysanoptera: thrips

• Intermediate metamorphosis • Narrow wings with a fringe of long hairs • Rasping-sucking mouthparts • Less than ¼ inch • Some are predators but most feed on plants Coleoptera: beetles & weevils

• Hardened outer wings (elytra) and membranous inner wings • Chewing mouthparts, complete metamorphosis • Larvae (scarabaeiform, campodeiform, elateriform, grubs) have hardened head capsule and 3 pairs of legs on thorax • Most diverse group of insects Beetles & Weevils

Lady beetle larva Boll weevil Tiger beetle

Lady beetle adult

Cucumber beetle White grubs Lepidoptera: moths & buerflies • Four well developed membranous wings covered with scales • Larvae have chewing mouthparts, adults have coiled sucking tube • Undergo complete metamorphosis • Larvae (eruciform, caterpillars) have 3 pairs of true legs on thorax and variable number of prolegs on abdomen Moths & Buerflies

Tent caterpillar

Monarch butterfly Cabbage looper

Yellowstriped Sugarcane borer armyworm Bag worm Diptera: flies & mosquitoes

• Adults have one pair of wings • Sponging or piercing (adults), mouth hooks or chewing (larvae) mouthparts • Undergo complete metamorphosis • Most larvae (vermiform; maggots) don’t have legs or head capsule Flies & mosquitoes Horse fly Fungus gnats

Tachinid fly

Yellow fever mosquito

Med fly Love bugs • Adults have two pairs of Hymenoptera: membranous wings bees, wasps, • Most have chewing ants mouthparts • Undergo complete metamorphosis • Social wasps and bees (may sng) and solitary wasps (predators and parasitoids) • Larva (eruciform, grubs) lack legs (except sawflies) Bees, wasps and ants

Carpenter bee Aphelinid wasp Mud dauber

Red imported fire ant

Paper wasp Sawfly larvae Causes of Injury to Foliage

• Physical damage (breakage, sunburn) • Plant diseases (viruses, fungi, bacteria) • Arthropod pests (sow bugs, pill bugs, millipedes, insects, mites) • Slugs and snails • Vertebrates (rabbits, squirrels, deer, etc.) Damage Caused by Arthropods

• Direct damage: – Removal of plant nutrients – Inducon of plant disorders • Indirect damage: – Honey dew secreon – Disease transmission – Reducon of aesthec quality Proper Idenficaon is Key

• Not all insects are pests (only 5% of all) • Informaon retrieval and communicaon • Save specimens for reference Insect Idenficaon Insects may be categorized by: • Differences in body parts and general anatomy (insect families) • Type of damage they cause (borers, girdles, leaf miners) • Feeding mechanisms or mouthparts (chewing, sucking, intermediate) Pest diagnosis based on feeding damage

• Chewing • Sucking • Intermediate Chewing Mouth Parts

• Caterpillars • Sawfly larvae • Beetles & grubs • Grasshoppers • (slugs & snails) Cabbage looper development

Early instar Early detecon: • Minimizes feeding damage • Facilitates control

Late instar Signs of chewing: Silk and Frass

Genista caterpillar on Texas Mountain Laurel Fall Webworms and Tent Caterpillars

Physical / mechanical control is best control alternave Bagworms

• Life spent in silken ‘bag’ • Females wingless • Eggs emerge mid-late May

Pest management: • Frequent removal of bags • Timing of applicaon • Use of Bt products like Dipel® Twelvespoed Cucumber Beetle

• Plants tolerate defoliaon • Damage is only caused during fruit development • Only large populaons require acon Flea Beetles

• Plants can tolerate defoliaon • Aesthec damage? White grubs

Larva Identification

Adult Treatment not required for less than 3- 5 grubs per 2 Snout Weevils Weevils have chewing mouth parts Grasshoppers and Crickets

• Behavior depends on density • May feed on many plants • Many species in Texas • May move large distances Leafcung Bees

Do not feed on leaves but use them to build nest Symptoms of Chewing Insects • Pieces & parts of leaves missing, oen in characterisc paerns • Silk associated with damage indicates caterpillar presence • Excrement underneath damage can indicate insect group present • Brown edges around damage indicates older damage Sucking Mouth Parts

• True bugs • Aphids & mealybugs • Whitefly & scales Yucca bug and damage Lace Bugs and damage

Note frass specks Leaf footed & Squash bugs

Leaf footed bug

Squash bug Whiteflies, Scales, Mealybugs & Aphids

• Honeydew or sooty mold indicates presence • May leave cast skins on leaves • Rapid populaon growth (outbreak) • Can quickly become resistant to inseccides Symptoms of Sucking Insects

• Spong, discoloraon or death of leaf ssue can be yellow or reddish to brown • Honey dew and sooty mold on leaves under infestaon indicate presence • Cast skins on underside of leaf indicates developing populaon Intermediate: Thrips

• Some feed on pollen inside developing flowers • Common in Spring, colonize gardens from wild flowers • Specks of frass are common when feeding on foliage • Transmit viral diseases; may become resistant Spider Mites

• Sppling, spong, “bronzing”, close to the midrib • Eggs clear & spherical, cast skins on underside of leaves • Heavily infested plant covered in silk • Beneficial mites much ‘faster’ than pest Other types of insect damage • Leaf mines by maggots, beetle larvae or caterpillars • Teasing apart of plant ssue by root maggots • Galls and deformed plant parts by cynipid wasps, psyllids, some thrips • Egg-laying damage by cicadas, thorn bugs (plant hoppers) Gall-Forming Insects and Mites

Fly (top) and mite galls Cynipid wasp galls Resources (field guides)

Wagner, D.L. 2005 Drees, B.M. & J. A. Evans, A.V. 2007 Jackman. 1998