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Insect Pests of Corn

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Title: Insect Pests of Corn


1
Insect Pests of Corn
  • Kelly V. Tindall
  • Area Extension Entomologist
  • Twin Falls County

2
Handbook of Corn Insects (1999)
  • Provides a description of US corn insect pests
    and their damage
  • Problem Idaho was not considered a corn
    producing state when published
  • Purchased from the Entomological Society of
    America (59.00)
  • This presentation highlights pests of corn
    likely to occur in Idaho, emphasizing on early
    season pests.
  • http//www.entsoc.org/Pubs/Books/Handbooks/Corn.ht
    m

3
  • http//www.entsoc.org/Pubs/Books/Handbooks/Corn.ht
    m

4
  • http//www.entsoc.org/Pubs/Books/Handbooks/Corn.ht
    m

5
Planted Seed Feeding Insects
  • Fire ants
  • Seedcorn beetles
  • Seedcorn maggot
  • Slugs
  • Thief ant
  • Wireworms

6
Seedcorn Beetles
  • Light brown/yellow brown body with broad dark
    stripe on each wing
  • Black head
  • Can be beneficial/ predacious BUT when prey is
    unavailable or limited, it feeds on seeds

7
Seedcorn Maggot
  • Adult gray, smaller and more slender than a
    house fly
  • Larvae damaging stage, creamy white body,
    tapered at the front end, no visible head or legs
  • Biology sporadic pest, more problematic when
    germination is slow, high levels of decaying
    organic matter (plants or manures)
  • Injury tunneling in the seed decreases vigor or
    causes complete destruction/decay, rarely foliar
    symptoms

8
Slugs
  • Description gray to pale cream like a snail
    without a shell 1-2 in
  • Biology wide host range including living or dead
    and decaying plant tissue plant residue favors
    population build-up prefer tender leaves of
    seedling-stage plants primarily feed at night or
    overcast days but often leave slime trials eggs
    need a moist habitat to develop
  • Monitoring place bait stations throughout the
    field to establish activity and numbers look for
    slime trails and interveinal feeding may need to
    bait more than once if populations are large and
    weather is particularly wet and cold.

9
Wireworms
  • Description cylindrical, light tan to reddish
    tan larvae, usually hard bodied
  • Biology prefer porous, well drained loam soils
    injury more severe when corn follows pastures,
    small grains and other forage crops
  • Injury feed on seeds before or during
    germination, bore in to seedlings below soil
    surface

10
Baits for Wireworms
  • Hole aprx. 4 X 10 inches 1-3 wk before planting
  • Place in grassy areas or areas of previous
    infestations

11
Baits for Wireworms
  • Hole aprx. 4 X 10 inches 1-3 wk before planting
  • Place in grassy areas or areas of previous
    infestations
  • ½ cup of mixture of non-treated wheat and corn
    seed, soak seed in water for 24h

12
Baits for Wireworms
  • Hole aprx. 4 X 10 inches 1-3 wk before planting
  • Place in grassy areas or areas of previous
    infestations
  • ½ cup of mixture of non-treated wheat and corn
    seed, soak seed in water for 24h
  • Fill remainder of hole with soil and mound

13
Baits for Wireworms
  • Hole aprx. 4 X 10 inches 1-3 wk before planting
  • Place in grassy areas or areas of previous
    infestations
  • ½ cup of mixture of non-treated wheat and corn
    seed, soak seed in water for 24h
  • Fill remainder of hole with soil and mound
  • Cover with a 3ft black plastic square, put soil
    on top to prevent wind removal (? soil temp and
    germination)

14
Baits for Wireworms
  • Hole aprx. 4 X 10 inches 1-3 wk before planting
  • Place in grassy areas or areas of previous
    infestations
  • ½ cup of mixture of non-treated wheat and corn
    seed, soak seed in water for 24h
  • Fill remainder of hole with soil and mound
  • Cover with a 3ft black plastic square, put soil
    on top to prevent wind removal (? soil temp and
    germination)
  • Minimum of 5-10 bait stations per 25-30 acre
    field
  • Check 2-3 days prior to planting 1 per bait
    economic infestation

15
Summary of Wireworm Trials Increase in Stand
16
Summary of Wireworm Trials Reduction in Damage
17
Root Feeding Insects
  • Carrot beetle larvae
  • Cornfield ant
  • Corn root aphid
  • Corn rootworm larvae
  • Grape colaspis larvae
  • Sugarcane beetle
  • Symphylans
  • Whitefringed beetle larvae
  • White grubs

www.ca.uky.edu
18
Carrot Beetle Larvae
  • Adult reddish-brown with stout legs, robust, and
    about 1/2 inch long
  • Adult damage economically, damaging stage feed
    on seedlings just below soil line making
    gouge-like wounds destroying the growing point
  • Larva C-shaped and white, resembling common
    white grubs with brown head
  • Larval damage feed on roots, usually not an
    economic threat
  • Biology overwinter as adults in the soil
    potential for infestation is greater no-till
    fields

19
Cornfield Ant
  • 1/12 1/10 inch
  • Brown to very dark
  • 1 segmented waist
  • Sporadic pest
  • Relationship with corn root aphids (CRA) and
    CRA retard growth plants turn yellow or red,
    then brown and die small ant mounds usually
    found near injured plants
  • Ants may tunnel along roots plants rarely die
    from ants

20
Corn Rootworms
Rootworms are worse in corn-corn rotations 90
of corn is treated with soil insecticides when no
rotation When rotated 25 of corn is treated
with soil insecticides
http//lamar.colostate.edu/gec/vg.htm
Marlin Rice
21
Western Corn Rootworm
  • Larva creamy white body, up to ½ in., dark brown
    head and anal plate on last abdominal segment
  • Adults light yellow to light green, 3 black
    stripes on wings (size of stripes vary)
  • Corn is the only known crop host therefore,
    rotations have been effective in control
  • HOWEVER, evidence suggests 2 biotypes one that
    lays eggs only on corn and one that will lay on
    soybeans making corn/soybean rotations
    ineffective

22
Summary of CRW Trials Reduction of Injury
23
Symphylans
  • AKA garden centipede
  • Immatures 6 pairs of legs gain 1 new pair with
    every molt
  • Adult 12 pairs of legs
  • Infrequent pest, often spotty damage
  • Damage occurs with 50-100/plant
  • Damaged plants are stunted and purple

24
White Grubs
  • In PNW Phyllophaga spp.
  • C-shaped and up to 1 inch
  • Orange-brown to brown head
  • 3 pairs of legs
  • Dark posterior
  • Injury occasional pests apparent when plants
    are 2-6in tall plants turn yellow or tan, wilt
    and die may turn purple from lack of phosphorous
    uptake

25
White Grubs vs Annual Grub
It is difficult to tell them apart but
important because the annual grub does not cause
stand loss like the true white grub.
26
White Grubs vs Annual Grub
To tell them apart you look at the raster.
Marlin E. Rice
True white grub 2 parallel rows of stiff hairs
in addition to scattered hairs
Annual grub only scattered white hairs
27
Foliage Feeders Seedlings
  • Armyworms
  • Billbugs
  • Carrot beetle adult
  • Chinch bug
  • Corn leafhopper
  • Cutworms
  • False chinch bug
  • Flea beetles
  • Hop vine borer
  • Leafrollers
  • Lesser cornstalk borer
  • Potato stem borer
  • Slugs
  • Southern corn leaf beetle
  • Stalk borer
  • Stink bugs
  • Sugarcane beetle adults
  • Thrips
  • Webworms
  • Wireworms

28
Armyworms
  • Four species cause significant injury
  • Armyworm
  • Beet armyworm
  • Fall armyworm
  • Yellowstriped armyworm
  • In PNW
  • Armyworm
  • Beet armyworm
  • Bertha armyworm
  • Western yellowstriped AW

29
Armyworm
  • Larva vary in color from dark greenish-brown to
    black long, pale white, orange, and dark brown
    stripes along the side of the body yellowish
    brown head dark band on the outer side of each
    proleg aprx. 1.5 in
  • Adult tan to light brown, tiny white spot
    centered on each forewing
  • Biology eggs are laid in rows or groups on
    leaves of host plants females tend to roll the
    leaf blade around the egg mass may build-up in
    grassy areas

Robin McLeod
30
Beet Armyworm
  • Larva light to dark green with a 2 light and 1
    dark stripes running the length of the body
    usually a dark spot above the second pair of
    legs inverted "Y on front of head
  • Adult Front wings light brown to gray marked
    with dark brown and white scales, round cream
    colored spot may be cream with an orange center
  • Biology eggs are covered with scales
  • Injury infrequent pest of corn can damage
    leaves and ears feed in the whorl and at the
    base of expanded leaves

31
Carrot Beetle Adult
  • Adult reddish-brown with stout legs, robust, and
    about 1/2 inch long
  • Adult damage economically, damaging stage feed
    on seedlings just below soil line making
    gouge-like wounds destroying the growing point
  • Larva C-shaped and white, resembling common
    white grubs with brown head
  • Larval damage feed on roots, usually not an
    economic threat
  • Biology overwinter as adults in the soil
    potential for infestation is greater no-till
    fields

32
Cutworms
  • Several species attack corn
  • Black cutworm
  • Bristly cutworm
  • Bronzed cutworm
  • Claybacked cutworm
  • Dingy cutworm
  • Glassy cut worm
  • Pale Western cutworm
  • Red Backed cutworm
  • Sandhill cutworm
  • Spotted cut worm
  • Variegated cutworm
  • Western bean cutworm
  • Damage and management is the same

33
Black Cutworm
  • Larva body gray with light brown stripe down the
    back greasy appearance inside pair of tubercles
    is about one-third to one-half the size of the
    outside pair pebbly skin texture dark brown or
    black head 1.6 in long.
  • Adults brownish-gray with a light silvery band
    on the wings
  • Biology overwinters as a pupa adults emerge in
    April and lay eggs larvae are underground of
    surface feeding during late March - early June
    two overlapping generations/year 2nd generation
    adults emerge in Aug. and Sept.
  • Monitoring seedling stage 2-3 wilted or cut
    plants or leaves in 10 ft at several sites in
    field insecticide application insecticides
    most effective on young larvae

www.uky.edu/Agriculture
34
Bronzed Cutworm
  • Larva dark brown body with bronze sheen with 3
    yellowish strips on body tan head color, 1.75 in
  • Adult Bronze sheen on purple forewing
  • Biology overwinters as eggs feed on crowns of
    grasses and cut plants major pest when corn is
    planted behind sod or pasture grass

35
Dingy Cutworm
  • Larva resembles black cutworm but the skin
    textures differ pale gray with ting of red
    V-shaped marking on abdominal segments, pale
    brown-gray head dingy CW has smooth skin the
    tubercles are of similar size,
  • Adult forewings are dark brown with bean-shaped
    markings
  • Biology overwinter as late instars begin
    feeding Mar. or Apr. regarded primarily as leaf
    feeders and rarely cut plants not considered an
    economic threat frequently occur in fields
    planted after clover or alfalfa

36
Glassy Cutworm
  • Larva glossy, semi-translucent greenish-white or
    grayish white, lacks body markings reddish brown
    heads aprx. 1.5 in
  • Adult nondescript, medium sized grayish miller
    moth with a scattering of dark markings
  • Biology most subterranean of the cutworms
    overwinters in the crowns of grass as small
    larvae and mature in the spring adults emerge in
    late June August eggs are laid on the soil
    near grass plants larvae hatch and feed on
    crowns before overwintering 1 generation/yr

37
Pale Western Cutworm
  • Larva they are grayish-white to a grayish-green
    color with no distinct markings on its body
    amber to black head 1.25 in
  • Adult gray to brownish white, heavy-bodied no
    distinct markings on the wings distinctive
    characteristic is the white under-sise of the
    wings
  • Biology overwinters as an egg larvae emerge and
    feed throughout spring prefers dry loose soils
    irrigated fields are rarely injured

38
Redbacked Cutworm
  • Larva light brown ot gray with 2 red stripes
    down back bordering median stripe yellow-brown
    head aprx. 1.5 in
  • Adults pale clay-yellow to dark red
  • Biology overwinters as eggs in soil severe pest
    in Canada

39
Sandhill Cutworm
  • Larva light tan, semi-translucent with several
    pale, chalky white, longitudinal stripes tan to
    dull red-brown head 1.3 in
  • Biology overwinters as a partially grown larva
    only occurs in very sandy soil feed almost
    entirely beneath the surface of the soil, so they
    usually cut the seedlings off below the growing
    point

40
Spotted Cutworm
  • Larva dull gray-brown black wedge-like markings
    begin half way down the back toward the end
    spotted appearance whitish head aprx. 1.5 in
  • Adult brown forewings with red or purple ting,
    pinkish trianglular spot on the outer margin and
    a moon-shaped spot near the center of each wing
  • Biology climbing cutworm night feeders
    overwinter as larvae prefers vegetable crops

41
Variegated Cutworm
  • Larva green-yellow to tan to nearly black, pale
    yellow marks on segments 4-7 W or crown shape on
    last abdominal segment 2 in
  • Adult faintly outlined spots on dark
    purple/brown forewing
  • Biology regarded primarily as leaf feeders and
    do not present a significant economic threat
    frequently present in fields planted after clover
    or alfalfa

42
Western Bean Cutworm
  • Description young larva dark brown with faint
    diamond shaped markings older larvae pale tan,
    gray-brown to pink gray with 3 short dark stripes
    along the first segment behind the head 1.5 in
  • Adult dark brown with white stripe on the outer
    edge of the wing
  • Biology eggs laid on the upper surface of corn
    leaves larvae hatch and feed in the whorl, silks
    or kernels can reduce kernels by 50-60
    overwinter as prepupae
  • Threshold 8 of plants have eggs and larvae when
    corn is at 95 tassel (Nebraska-grain yields)

43
Summary of Cutworm Trials Increase in Stand
44
Summary of Cutworm Trials Reduction in Damage
45
General Cutworm Information
  • Overwintering stage is important
  • Larvae ready to feed pupae mate and lay eggs
  • Proper identification and feeding habit are
    important
  • Foliar feeder or cutter (only cutters are
    included for application decisions)
  • Thresholds (Begin scouting at seedling stage)
  • cutworms lt3/4 in and 2-3 of the plants are
    wilted or cut
  • cutworms gt1 inch and 5 of the plants are cut
  • poor plant stands (lt20,000) thresholds should be
    lowered
  • Timing of insecticide application is critical
  • Insecticides are only effective if they come in
    contact with larvae many are above ground as
    small larvae only
  • Plants should withstand cutworm damage V5 and
    bigger

46
False Chinch Bug
  • Nymphs ash-gray with brown-white mottling on the
    back and red mottling on the abdomen
  • Adults dirty gray with brown and black markings
    1/8 in
  • Biology unpleasant smell prefer mustard and
    beets rarely pests of corn may be problematic
    in times of drought gregarious
  • Injury excessive fluid removal salivary toxins
    causes wilting or death of leaf tips or whole
    plant

47
Leafrollers
  • Rarely pests of corn
  • Can injury 4-8 leaf plants
  • More common on borders near grassy areas
  • Tie 2-3 young leaves together with silk and
    consume tissue within the web

Marlin E. Rice
  • Spotted fireworm
  • Torticid larva

48
Slugs
  • Description gray to pale cream like a snail
    without a shell 1-2 in
  • Biology wide host range including living or dead
    and decaying plant tissue plant residue favors
    population build-up prefer tender leaves of
    seedling-stage plants primarily feed at night or
    overcast days but often leave slime trials eggs
    need a moist habitat to develop
  • Monitoring place bait stations throughout the
    field to establish activity and numbers look for
    slime trails and interveinal feeding may need to
    bait more than once if populations are large and
    weather is particularly wet and cold.

49
Stink Bugs
  • Description shield shaped multiple colors
  • Biology primarily seed feeders but will feed on
    foliage if seeds are limited some predaceous
    species
  • Injury common in fields associated with winter
    annual weeds stunted plants production of
    tillers wrinkled leaves holes, either scattered
    or in repeating patterns up to 1 in holes may be
    outlined by a yellow to brown color whorl leaves
    unable to expand may occur on mid-whorl-stage
    plants but most common on seedlings up to 4th
    true-leaf stage Insecticide control is rarely
    warranted because most injury is seen and it is
    too late.

Marlin E. Rice
50
Good and Bad Stink Bugs
BAD
  • General rules of good vs bad
  • BAD rounded shoulders
  • GOOD -spines on the shoulders
  • THERE ARE EXCEPTIONS!!!

GOOD
BAD
BAD
51
Good and Bad Stink Bugs
  • General rules of good vs bad
  • BAD rounded shoulders
  • GOOD -spines on the shoulders
  • BAD - long thin mouthparts
  • GOOD short stout mouthparts

52
Thrips
  • Description very slender, tan in color adults
    with two pairs of feathery wings rasping mouth
    parts 1/16 in
  • Biology sporadic pest infestations more severe
    in drought conditions and near weedy hosts
  • Injury rasp plant tissue and suck plant juices
    leaves appear sand-blasted whitish in color with
    yellow streaking can resemble diseases
    insecticide rarely applied

53
Webworms
  • Description usually pale gray-brow with black
    spots and coarse hairs aprx. 1 in
  • Biology several species in US usually worse in
    fields following sod
  • Injury sporadic pest defoliate leaves, feed on
    leaf margins sometimes feed just below soil
    surface killing the growing point

54
Wireworms
  • Description cylindrical, light tan to reddish
    tan larvae, usually hard bodied
  • Prefer porous, well drained loam soils
  • More severe injury when corn is planted behind
    pastures, small grains and other forage crops
  • Injury feed on seeds before or during
    germination, bore in to seedlings below soil
    surface

55
Plant-fluid Feeding Insects
  • Aphids
  • Chinch bugs
  • Corn delphacid
  • False chinch bug
  • Leafhoppers
  • Spider mites
  • Stink bugs
  • Thrips
  • Twolined spittlebug

56
Aphids
  • Six species in North America on corn
  • Bean Aphid
  • Bird Cherry-Oat Aphid
  • Corn Leaf Aphid
  • Corn Root Aphid
  • Greenbug
  • Potato Aphid
  • Most have worldwide distribution
  • All aphids have cornicles (tube-like projections
    at the end of their abdomen)
  • Feed on plant juices
  • Some transmit disease

57
Bean Aphid
  • 1/16-1/8 inch
  • Olive green to black
  • Considered a minor pest
  • Individuals of old colonies may develop a white
    waxy pubescence
  • Potential vectors of maize dwarf mosaic virus
    (MDMV) and barley yellow dwarf virus

58
Bird Cherry-Oat Aphid
  • Adults 1/16 3/32 inch
  • Dark olive to green with an orange, red,
    rust-colored patch near the cornicles
  • Usually found on husks, leaves or lower stalks
  • Significant loss of corn yields
  • Transmits barley yellow dwarf virus, which is
    relatively harmless to corn but corn can be a
    reservoir for the virus, aiding the spread to
    cereal grains.

59
Corn Leaf Aphid
  • Pale blue-green black cornicles with black spots
    on the abdomen at the cornicle base
  • As they age, they change colors a dark green to
    black.
  • Do not overwinter north of Texas, but they
    migrate as far north as Canada
  • Occasional pest
  • Primary vector of maize dwarf mosaic virus
    (MDMV), causing stunting and mottling of plants.

60
Greenbug
  • Pear-shaped body yellow-green to blue-green with
    dark green strip down the middle of the back
    cornicles are pale with dark tips
  • Not considered a pest of corn is a problem in
    sorghum a new biotype may develop that is
    injurious to corn
  • Found on the underside of leaves inject salivary
    toxins that cause a variety of plant responses
  • Transmits barley yellow dwarf virus and may
    transmit maize dwarf mosaic virus

61
Potato Aphid
  • Pear-shaped 1/16-1/8 inch usually green, but
    may be yellow, pink or magenta have distinctive
    red eyes
  • Problematic in vegetables, only a minor pest of
    corn
  • Transmits maize dwarf mosaic virus

62
Spider Mites
  • General pierce leaf tissue feeding on cell
    contents drought stressed plants more prone to
    infestation
  • Two-spotted spider mite
  • Produces copious webbing
  • Food balls concentrated on the sides of the
    abdomen
  • Chlorotic tissue evenly distributed across leaf
  • Uniformly distributed on the plant
  • Banks grass mite
  • Green food balls around periphery of abdomen
  • Chlorotic tissue begins near the midrib and
    spreads to the basal portion of leaf
  • Concentrated on lower 1/3 of plant and density
    decline as move up the plant

63
Stink Bugs
  • Description shield shaped multiple colors
  • Biology primarily seed feeders but will feed on
    foliage if seeds are limited some predaceous
    species
  • Injury common in fields associated with winter
    annual weeds stunted plants production of
    tillers wrinkled leaves holes, either scattered
    or in repeating patterns up to 1 in holes may be
    outlined by a yellow to brown color whorl leaves
    unable to expand may occur on mid-whorl-stage
    plants but most common on seedlings up to 4th
    true-leaf stage Insecticide control is rarely
    warranted because most injury is seen and it is
    too late.

Marlin E. Rice
64
Thrips
  • Description very slender, tan in color adults
    with two pairs of feathery wings rasping mouth
    parts 1/16 in
  • Biology sporadic pest infestations more severe
    in drought conditions and near weedy hosts
  • Injury rasp plant tissue and suck plant juices
    leaves appear sand-blasted whitish in color with
    yellow streaking can resemble diseases
    insecticide rarely applied

65
Foliage Feeding Tissue Removal
  • Armyworms
  • Cattail caterpillar
  • Cereal leaf beetle
  • Corn earworm
  • Corn rootworm adult
  • Cutworms
  • European corn borer
  • Flea beetle
  • Grape colaspis adults
  • Grasshoppers
  • Japanese beetle
  • Leafroller
  • Mexican rice borer
  • Mormon cricket
  • Neotropical corn borer
  • Southern cornstalk borer
  • Southwestern corn borer
  • Sugarcane borer
  • Whitefringed beetle adult
  • Wollybear (yellow)

66
Armyworms
  • Four species cause significant injury
  • Armyworm
  • Beet armyworm
  • Fall armyworm
  • Yellowstriped armyworm
  • In PNW
  • Armyworm
  • Beet armyworm
  • Bertha armyworm
  • Western yellowstriped AW

67
Cattail Caterpillar
  • Description yellow, orange, and black markings
    tufts of black and white hairs on orange bumps on
    the body black head with white spots on the
    face aprx. 1.75 in
  • Injury rarely reaches pest status small larvae
    windowpane feeding large larvae eat all foliage
    except the midrib

68
Cereal Leaf Beetle
  • Description Adult - elytra (wings) shiny blue,
    black body and head, red pronotum, red to orange
    legs with black tarsi Larva pale yellow to
    orange, cover body in mucous and fecal matter
    appearing shiny black
  • Biology invasive species infrequent pest,
    usually around small grains adults feed between
    the veins on upper leaf surface of corn
    excellent control from parasitoids

69
Corn Earworm
  • Larva Vary in color from yellow, brown, red, to
    green with prominent bands of cream, pink, green
    or yellow dark yellow or orange head 1.6 in
  • Adult brown to olive green forewings with dark
    spot near the center of the wing
  • Biology pest of several crops in corn
    consumes leaves, tassels, silks, and kernels

70
Corn Rootworm Adults
University of Kentucky
Photo by Bastiaan M. Drees
http//lamar.colostate.edu/gec/vg.htm
Marlin Rice
71
Cutworms
  • Several species attack corn
  • Black cutworm
  • Bristly cutworm
  • Bronzed cutworm
  • Claybacked cutworm
  • Dingy cutworm
  • Glassy cut worm
  • Pale Western cutworm
  • Red Backed cutworm
  • Sandhill cutworm
  • Spotted cut worm
  • Variegated cutworm
  • Western bean cutworm
  • Damage and management is the same

72
Grasshoppers
  • Four economically important and all are present
    here

Marlin E. Rice
Marlin E. Rice
73
Redlegged Grasshoppers
  • Description brownish red pinkish-red or bluish
    tibia on the jumping leg has a line of black
    spines on the hind margin of the tibia ¾" 1"
    long
  • Biology widely distributed wide host range but
    prefers dense stands of weeds and grasses may
    severely damage alfalfa, clover, soybeans, small
    grains, various legumes, corn, vegetables and
    tobacco wasteful feeder, leaving as much as 75
    of the plant clipped but unconsumed

74
Differential Grasshopper
  • Description yellowish or greenish gray the
    femur of the hind leg is marked with black
    chevrons adults are 1 ½" 1 ¾
  • Biology frequently found in the west in various
    habitats of mixed vegetation prefers forbes
    nymphs can be a pest in small grains, alfalfa and
    other hay crops as adults they may fly into
    corn, large populations will destroy a young
    cornfield in 3-4

75
Two-striped Grasshopper
  • Descriptions grayish or brownish green with two
    distinct yellow strips extending from the head to
    the wing tips have a distinct black band on the
    top of the femur of the hind leg relatively
    large grasshoppers 1¼" 2
  • Biology eats a wide variety of different plants
    can cause extensive damage in small grains,
    alfalfa, soybeans and corn is a wasteful feeder,
    not consuming most of what is clipped may
    completely destroy the crop

76
Migratory Grasshoppers
  • Description brown to gray with a distinctive
    black mark behind its eye has a slight hump
    behind the spine on its underside, between the
    middle pair of legs about 1" long
  • Biology damages crops more than any other
    species of grasshopper prefers to feed on weeds
    and forbes can be a pest in small grains,
    alfalfa, clover, corn, and vegetables strong
    flier and disperses readily

77
Leafrollers
  • Rarely pests of corn
  • Can injury 4-8 leaf plants
  • More common on borders near grassy areas
  • Tie 2-3 young leaves together with silk and
    consume tissue within the web

Marlin E. Rice
  • Spotted fireworm
  • Torticid larva

78
Mormon Cricket
  • Description Adults - black with small useless
    wings females have a long ovispositor aprx. 1
    in. Young nymphs- black with white markings
    older nymphs green to black
  • Biology large host range feed on edges of corn
    leaves moving inward overwinter as eggs passes
    through 7 instars in 60-90 days

79
Foliage Feeders Miners
  • Description larva pale-green to yellow white
    0.25 in
  • Biology eggs laid on corn leaf surfaces, larvae
    hatch, larvae tunnel into corn leaves, feeding
    internally, scraping green leaf tissue, leaving
    behind transparent mines can complete its life
    cycle in 3 wk
  • Injury 7-leaf corn 35 leaf area destroyed
    no yield loss 50 percent leaf area destroyed
    2 loss 10-leaf corn 20 leaf area
    destroyed no yield loss 50 percent leaf area
    destroyed 6 yield loss

80
Stem-Boring Insects
  • European corn borer
  • Lesser cornstalk borer
  • Mexican rice borer
  • Neotropical corn borer
  • Southern cornstalk borer
  • Southwestern corn borer
  • Sugarcane borer
  • Stalk borer
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