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Insect Pests of Grain Sorghum, Soybean and Sunflower

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Insect Pests of Grain Sorghum, Soybean and Sunflower Tom A. Royer Oklahoma State University NCIS MPCI & Crop-Hail Sunflower, Soybeans, Cotton & Grain Sorghum School – PowerPoint PPT presentation

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Title: Insect Pests of Grain Sorghum, Soybean and Sunflower


1
Insect Pestsof Grain Sorghum, Soybean and
Sunflower
  • Tom A. Royer
  • Oklahoma State University

NCIS MPCI Crop-Hail Sunflower, Soybeans,
Cotton Grain Sorghum School August 23, 2006
2
Insect Pests of Grain Sorghum
  • There are many potential pests that feed on the
    foliage and panicle. The results of their
    activities can cause seedling death, lodging and
    unfilled seed

3
Insect Pests of Soybean
  • In the past, there were few pests that caused
    significant damage to soybean. In resent years,
    several pests have mad their presence felt
    throughout the soybean growing region.

4
Insect Pests of Sunflower
  • Sunflowers are native to North America, therefore
    we have a wide variety of insect pests and their
    associated natural enemies.
  • Damage occurs to the seedling, foliage, stalk,
    developing head,and seed.

5
Insect Pests of Grain Sorghum, Soybean and
Sunflower
  • There are numerous pests of these crops, but I
    will focus on the pests that can cause damage
    symptoms that resemble hail damage

6
Insect Pests of Grain Sorghum, Soybean and
Sunflower
  • Seed/seedling feeders
  • Stem/stalk feeders
  • Foliage feeders
  • Seed feeders

7
Seed/seedling Feeders in Sorghum, Soybean and
Sunflower
  • Wireworms would be a problem for stand
    establishment in cool soils that delay rapid
    early growth (early-planted crop). Feed on
    germinating seed and newly emerged seedlings.

8
Seed/seedling Feeders in Sorghum, Soybean and
Sunflower
  • Seed corn maggots are a problem in cool soils
    with higher organic matter. (early-planted crop).
    Feed on germinating seed.

9
Seedling feeders in Sorghum, Soybean and Sunflower
  • Cutworms several species attack these crops
  • Black cutworm
  • Dingy cutworm
  • Darksided cutworm
  • Sandhill cutworm
  • Many others

10
Seedling feeders in Sorghum, Soybean and Sunflower
  • Look for stand loss
  • Look for weak, slow
  • growing plants
  • Slow growing conditions (cool weather)
    favors cutworm damage
  • Follow-up with presence of insect

11
Seedling feeders in sorghum
  • Chinch bugs
  • Adults 1/6 inches, black body and white wing
    covers
  • Nymphs reddish-brown with band of white across
    back
  • 40-day lifecycle

12
Seedling feeders in sorghum
Feed in groups at base of plant, may often feed
below soil line, 7-10 bugs can stunt small
seedlings
Migrate from wheat, often see most severe injury
at edge of field
13
Sorghum stalk feeders
  • Southwestern Corn Borer
  • More of a pest of corn, it occasionally attacks
    sorghum
  • Hollows out stem, causing lodging. Not a major
    pest of sorghum

14
Soybean stem feeders
  • Three-cornered alfalfa hopper
  • Piercing-sucking mouthparts. It feeds and
    circles around the stem effectively girdling it.

15
Soybean stem feeders
  • Soybean Stem Borer
  • Longhorned beetle.
  • Larva is damaging stage, tunneling in stem. They
    overwinter below girdle, in stem.

16
Soybean stem feeders
  • Soybean Stem Borer
  • Longhorned beetle.
  • Larva is damaging stage, tunneling in petioles
    and stems. They overwinter below girdle, in stem.
  • They also feed on giant ragweed, cocklebur
  • Larvae tunnel downward, causes lodging on mature
    plants
  • Damage often remains unnoticed because it occurs
    so late.

17
Sunflower stem feeders
  • Stem weevils
  • Sunflower stem weevil (Cylindrocopturus
    adspersus)
  • Black stem weevil (Apion occidentale)
  • Dectes stem larva

18
Sunflower stem feeders
  • Larvae feed on stem cortex, moving down stem as
    they mature
  • Cause weakened stalks, particularly a problem
    when harvest is delayed.
  • Can help transmit Phoma stem rot

19
Soybean defoliators
Fall Armyworm
Corn earworm
Grasshopper
20
Sorghum defoliators
  • Fall armyworm/corn earworm
  • Damages both whorl and panicle, but most often
    seen in whorl
  • Control in whorl is generally not profitable

21
Sunflower defoliators
Grasshoppers
Thistle Caterpillar
Sunflower Beetle
22
Defoliators In SunflowerNature of Damage
  • Pests that feed on foliage. Chewing mouthparts.
  • Damage leaves, causing indirect damage to
    sunflower yield
  • Reduce photosynthesis, slow growth, shift plants
    emphasis to compensating for foliage loss
  • Probably information that would help with
    assessing yield loss from hail.

23
Sorghum seed feeders
  • Corn earworm/Fall armyworm
  • Damages both whorl and panicle
  • When feeding on head, they will eat seed until
    it passes soft dough.

24
Sorghum seed feeders
  • Corn earworm/Fall armyworm
  • Damages both whorl and panicle
  • When feeding on head, they will eat seed until it
    passes soft dough.

25
Sorghum seed feeders
  • Sorghum midge
  • Larvae feed for 7 - 9 days, total lifecycle is
    about 2 weeks
  • Larvae completely destroy the seed
  • Adults emerge, leaving white pupal case dangling
    from floret and can re-infest late blooming
    suckers or fields. Heads are blasted.
  • Johnson grass is alternate host do not
    overwinter well in Oklahoma

26
Soybean seed feeders
  • Corn earworm
  • Also known as podworm, feeds on foliage and
    maturing pods
  • Occurs in mid to late season
  • Can severely injure pods

27
Soybean seed feeders
  • Bean leaf beetle
  • Overwinters as adult 1-3 generations
  • Feeds on foliage and been pods.
  • Most damaging to pods.

28
Soybean seed feeders
  • Stinkbugs
  • Typical stinkbug shape, green about 7/8 to 1
    inch long
  • Piercing-sucking mouthparts
  • Lay barrel-shaped eggs, often coppery colored

29
Soybean seed feeders
  • Piercing-sucking mouthparts inserted into
    developing pods
  • Cause shriveled, misshapen, and discolored seeds
    that are lower in weight

30
Sunflower seed feeders
  • Head clipper weevils chew holes around the stem,
    effectively girdling it. It breaks over, and
    could be mistaken for hail injury.

31
Sunflower seed feeders
  • Sunflower midge is a pest, usually in the
    northern plains, that causes the head grow in a
    distorted way (folding, convoluted). It could
    mimic hail damage under the right circumstances.

32
Grasshoppers in Soybeans
  • Grasshoppers will feed on pods, causing chewing
    injury. This also allows entry for seed
    disease-causing organisms.

33
Grasshoppers in Sorghum
  • Grasshoppers will feed on developing seed.
  • Grasshoppers may be more of a problem in
    conservation tillage because they may be laying
    eggs in fields which wont be disturbed by
    tillage. Eggs may survive better, hatch slightly
    later, and grasshoppers may be more uniformly
    distributed in the field.

34
Grasshoppers in Sunflowers
  • Grasshoppers are a sporadic problem in Oklahoma,
    because they can build up in large numbers and
    caused physical damage to the leaves and seed.

35
Insect Pestsof Grain Sorghum, Soybean and
Sunflower
  • Tom A. Royer
  • Oklahoma State University

NCIS MPCI Crop-Hail Sunflower, Soybeans,
Cotton Grain Sorghum School August 23, 2006
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