Approaches To Identification

There are three guiding principles to identification that, if followed, enhance correct identification. Remember that some species can be identified only by authorities, and some cannot be distinguished based only on appearance, but most serious pests are readily distinguished with but little effort. You may need to use some low-level magnification such as a 10 x hand lens, and such equipment is inexpensive and easy to use.

  1. Although there are numerous pests, most are easily assigned to groups based on easy-to-discern characters such as the number of legs or wings and the type of mouthparts. With a little effort it is easy to distinguish such common groups as aphids, caterpillars, whiteflies, and wireworms.
  2. Behavior is as important as appearance in distinguishing among pests. How or where a pest feeds is critical knowledge. The presence of silk webbing, the positioning of eggs, and other aspects of pest biology often are key elements in distinguishing the pests. When attempting to identify an unknown pest, try to observe as much as possible about pest behavior and plant damage.
  3. Details are important; look carefully at the pest and its damage, and do not trust your memory. Collect the pest you want to identify, do not just kill it. No one who is unfamiliar with the pest's identity can anticipate what characters will be critical in distinguishing it from its relatives. It is entirely too easy not to notice the number of wings or the color of the legs, or not to remember to count the stripes or spots.

Compare the written descriptions with the physical evidence carefully. Do not ignore aspects of the description because you are unfamiliar with the termi nology. Entomologists, like members of all scientific disciplines, use technical words to describe the physical appearance and behavior of their subjects of study. In this book the use of terminology is minimized, and terms are described in the glossary and illustrated with diagrams.

If a pest poses a major economic threat to a crop and you are uncertain of its identity, there are several available sources of assistance. The principal source in the United States is the Cooperative Extension System associated with the Land-Grant University found in each state. A cooperative extension service office is

Quick guide to orders of vegetable-feeding insects

Order of insects

Common name

Example of adult

Front wings

Hind wings

Coleoptera

Beetles, weevils; grubs

Thickened, hard, meeting in straight lines on back

Thickened, hard, meeting in straight lines on back

Membranous, folding beneath front wings

Dermaptera

Earwigs

Diptera

Files, maggots

Hemiptera

Plant, seed, stink, lace and leaf-footed bugs

Leaf Identification Veg

Short, thickened (if present)

Large, membranous, folding fan-like under front wings (if present)

Membranous

Absent

Thickened basally, membraous distally

Membranous normally found in each county, and the employees are commonly called county agents. The county agents often can assist with identification, and if they cannot they will forward the pest to the state university for identification. Research centers and experiment stations are other good sources of expertise, in both Canada and the United States. Crop consultants pro vide identification and pest management recommendations on a for-fee basis and usually can be found in important agricultural areas. You can access considerable additional information to aid in identification if you have access to the Internet. Suggested sources of supplementary information and assistance are found in Appendix B.

Quick guide to orders of vegetable-feeding insects (Continued)

Antennae Mouthparts Other features Example of immature Immature features

Quick guide to orders of vegetable-feeding insects (Continued)

Antennae Mouthparts Other features Example of immature Immature features

Vegetables Resemble Organs

Moderately long, thread-like

Chewing

Large forceps-like cerci

Resemble adults except for reduced wings

Short, variable in from Lapping-sucking

Small balancing organs (halteres) in place of hind wings

Head reduced; legs absent

Usually moderately long four to five segments

Piercing-sucking, originating at front of head

Sometimes resembling beetles

Resemble adults except for reduced wings

26

Handbook of Vegetable Pests Quick guide to the important orders of vegetable-feeding insects (Continued)

Order of insects

Common name Example of adult Front wings

Hymenoptera

Aphids, leafhoppers, whiteflies, psyllids

Sawflies, ants

Vegetable Garden Insects Identification
Membranous

Membranous

Membranous

Membranous

Membranous, smaller than front wings

Lepidoptera

Orthopetera

Thysanoptera

Moths, butterflies, caterpillars, cutworms, loopers, webworms

Grasshoppers, crickets

Thrips

Moths, butterflies, caterpillars, cutworms, loopers, webworms

Broad, with scales

Thickened (if present), many veins

Broad, with scales

Thickened (if present), many veins

Very slender, with fringe of long hairs

Broad, with scales

Large, membranous, folding fan-like under front wings (ifn present)

Very slender, with fringe of long hairs

Quick guide to the important orders of vegetable-feeding insects (Continued) Antennae Mouthparts Other features Example of immature Immature features

Usually short

Piercing-sucking, originating at back of head

Extremely diverse, sometimes with waxy or threadlike axudates

Often resemble adults, but sometimes flattened

Thread-like

Chewing

Leg number variable, sawflies with seven pairs of prolegs in addition to thoracic legs

Usually moderately long, thread-like, feathery, or clubbed

Coiled sucking tube

Two to five pairs of prolegs in addition to thoracic legs

Short

Minute, piercing- Minute in size sucking

28

Handbook of Vegetable Pests Quick guide to the adults of important families of vegetable-feeding beetles

Family

Common name Example of adult Antennae

Seed beetles and weevils

Chrysomelidae Flea beetles

Scarabaeidae Png

Tortoise beetles

Leaf beetles

Scarabaeidae Png

Curculionidae

Weevils

Moderately long, weakly clubbed or branched

Moderately long, thread-like

Short to moderately long, thread-like

Moderately long

Tip of abdomen exposed, not covered by elytra

Small; often metallic

Pronotum and elytra expanded, flaring over legs; colorful

Elongate body form; colorful

Short to moderately Elongate head forming long, elbowed and shout clubbed

Coccinellidae Lady beetles

Short, clubbed

Conves; colorful, spotted

Quick guide to the adults of important families of vegetable-feeding beetles (Continued)

Family

Common name

Example of adult

Antennae

Other features

Elateridae Click beetles

Meloidae Blister beetles

Scarabaeidae Scarab and June beetles

Short, branched Elongate

Moderately long, thread-like

Colorful or metallic

Short, branched or Convex; legs spiny clubbed

Quick guide to the adults of important families of vegetable-feeding flies

Family

Common name

Example of adult

Antennae

Other features

Agromyzidae Leafminers

Anthomyiidae Root maggots and leafminers

Otididae Picture-wing flies

Scarabaeidae Png
Short

Small; wings transparent

Medium size; wings transparent; legs medium length

Short to moderately Patterned wings long

Quick guide to the adults of important families of vegetable-feeding flies (Continued)

Family Common name Example of adult Antennae Other features

Family Common name Example of adult Antennae Other features

Quick guide to the adults of important families of vegetable-feeding bugs

Family

Common name

Example of adult

Antennae

Other features

Coreidae

Squash and leaffooted bugs

Moderately long, four segments

Front wing veins highly branched

Lygaeidae

Seed bugs

Moderately long, four segments

Small size

Miridae

Plant bugs

Pentatomidae Stink bugs

Stink Bug Identification Guide

Moderately long, four segments

Slender body

Moderately long, five segments

Shield-shaped body

Pest Identification

31

Quick guide to the adults of important families of vegetable-feeding Homoptera

Family

Common name Example of adult Antennae

Other features

Whiteflies

Aphididae

Aphids

Cicadellidae

Leafhoppers

Psyllidae

Psyllids

Thread-like, seven segments

Thread-like, three to six segments

Small

Long, nine to eleven segments

Opaque white wings

Wings transparent; cornicles usually present

Front wings thickened and opaque

Wings transparent; cornicles absent

Quick guide to the adults of important families of vegetable-feeding moths and butterflies

Family Common name Example of adult Wings Other features

Arctiidae

Tiger moths

Front wings much longer than hind wings

Nocturnal; robust body, moderately large

Gelechiidae

Leafminer moths

Fringed

Nocturnal; small size

Quick guide to the adults of important families of vegetable-feeding moths and butterflies (Continued)

Family

Common name

Example of adult

Wings

Other features

Noctuidae

Pyralidae

Sphingidae

Papilionidae

Armyworms, cutworms, and loopers

Borers, webworms

Hawk or sphinx moths

Swallowtails

Borers, webworms

Cut Worms Webworms

Muted colors, usually Nocturnal; robust body, brownish moderately large

Wings form triangle when at rest

Nocturnal; palps protrude markedly from head, small to medium size

Front wings long and Nocturnal; large size pointed

Hind wing with Diurnal; large size protruding lobe or "tail"

Pieridae

White and sulfur butterflies

White or yellow with Diurnal; moderate size black spots

Family

Quick guide to the adults of important families of vegetable-feeding grasshoppers and crickets

Common name

Example of adult

Antennae

Other features

Acrididae Grasshoppers

Gryllidae Field crickets

Gryllotalpidae Mole crickets

About one-half length Medium to large body of body size; usually colorful

Length of body or longer

Medium body size; color black

About length of pronotum

Front legs enlarged for digging; color brownish

Quick guide to major noninsect groups of pests affecting vegetables

Class ofNoninsects

Common name Example of adult Front wings

Mites

None

Quick guide to major noninsect groups of pests affecting vegetables (Continued)

Aetennae

Mouthparts

Other features

Immature features

Minute

Piercing-sucking

Usually 4 pairs of legs

Resemble adults

Short to moderately long

Chewing

Three pairs of legs

Resemble adults

Minute

Chewing

Two pairs of legs per body segment

Resemble adults

Extrudable

Hidden

Produce mucus; shell present or absent

Resemble adults

Minute

Chewing

Seven pairs of legs

Resemble adults

Moderately long

Chewing

12 pairs of legs

Resemble adults

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