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

Oklahoma State University

Insect Pestsof Grain Sorghum, Soybean and Sunflower

Tom A. Royer

Oklahoma State UniversityNCIS MPCI & Crop-Hail

Sunflower, Soybeans, Cotton & Grain Sorghum School

August 23, 2006


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


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.


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.

Insect Pests of Sunflower


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


Insect Pests of Grain Sorghum, Soybean and Sunflower

Seed/seedling feeders

Stem/stalk feedersFoliage feedersSeed feeders


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.


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.


Seedling feeders in Sorghum, Soybean and Sunflower

Cutworms: several species attack these crops– Black cutworm– Dingy cutworm– Darksided cutworm– Sandhill cutworm– Many others


• Look for stand loss• Look for weak, slow growing plants• Slow growing conditions (cool weather) favors cutworm damage • Follow-up with presence of insect

Seedling feeders in Sorghum, Soybean and Sunflower


Chinch bugs: – Adults: 1/6 inches,

black body and white wing covers

– Nymphs: reddish-brown with band of white across back

– 40-day lifecycle

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

Seedling feeders in sorghum


Southwestern Corn Borer:

– More of a pest of corn, it occasionally attacks sorghum

– Hollows out stem, causing lodging. Not a major pest of sorghum

Sorghum stalk feeders


Three-cornered alfalfa hopper

– Piercing-sucking mouthparts. It feeds and circles around the stem effectively girdling it.

Soybean stem feeders



Soybean Stem Borer– Longhorned beetle.– Larva is damaging stage,

tunneling in stem. They overwinter below girdle, in stem.



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.


Stem weevils:– Sunflower stem weevil

(Cylindrocopturus adspersus)– Black stem weevil (Apion occidentale)

Dectes stem larva

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

Sunflower stem feeders


Fall Armyworm Corn earworm

Grasshopper

Soybean defoliators


Fall armyworm/corn earworm:

– Damages both whorl and panicle, but most often seen in whorl

– Control in whorl is generally not profitable

Sorghum defoliators


Grasshoppers

Thistle Caterpillar

Sunflower Beetle

Sunflower defoliators


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 plant’s emphasis to compensating for foliage loss

Probably information that would help with assessing yield loss from hail.


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”.



Corn earworm/Fall armyworm:

– Damages both whorl and panicle

– When feeding on head, they will eat seed until it passes “soft dough”.



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


Corn earworm– Also known as podworm,

feeds on foliage and maturing pods

– Occurs in mid to late season

– Can severely injure pods

Soybean seed feeders


Bean leaf beetle– Overwinters as adult: 1-3

generations– Feeds on foliage and

been pods. – Most damaging to pods.



Stinkbugs– Typical “stinkbug” shape,

green about 7/8 to 1 inch long

– Piercing-sucking mouthparts

– Lay barrel-shaped eggs, often coppery colored



Piercing-sucking mouthparts inserted into developing pods

Cause shriveled, misshapen, and discolored seeds that are lower in weight



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

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.

Sunflower seed feeders


Grasshoppers in Soybeans

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


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 won’t be disturbed by tillage. Eggs may survive better, hatch slightly later, and grasshoppers may be more uniformly distributed in the field.


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.


Insect Pestsof Grain Sorghum, Soybean and Sunflower

Tom A. Royer

Oklahoma State UniversityNCIS MPCI & Crop-Hail

Sunflower, Soybeans, Cotton & Grain Sorghum School

August 23, 2006

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

Documents

sorghum slide

oklahoma state university

hail damage slide

unfilled seed slide

attacks sorghum

potential pests

numerous pests

wide variety of insect