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