Wheat Insect Wheat Insect Pest Pest

ManagementManagementbyby

Dr. Jack BaldwinDr. Jack BaldwinDept. of EntomologyDept. of Entomology

LSU AgCenterLSU AgCenter

True Armyworm Fall True Armyworm Fall Armyworm Armyworm

Both have four abdominal prolegs and are about 1.5 inches in length Both have four abdominal prolegs and are about 1.5 inches in length

when full grown.when full grown.

Fall ArmywormFall Armyworm Reported to be a pest Reported to be a pest

on seedling wheat in on seedling wheat in the fall.the fall.

Brownish color, but Brownish color, but varies from green to varies from green to almost black.almost black.

Dark head with Dark head with prominent inverted Y on prominent inverted Y on front.front.

Spines and hairs on body.Spines and hairs on body. 4 black spots arranged in 4 black spots arranged in

square on top of 8square on top of 8thth abdominal segment.abdominal segment.

Worm Damage to Seedling Worm Damage to Seedling Wheat in FallWheat in Fall

Suspected Pest/s: Fall Armyworm and Suspected Pest/s: Fall Armyworm and CutwormCutworm

Stand loss (November)

Clipped seedlings

True ArmywormTrue Armyworm Greenish color, but Greenish color, but

varies.varies. Brownish head with Brownish head with

honeycombed honeycombed markings.markings.

Smooth body, no hairs Smooth body, no hairs or spines.or spines.

Orange stripes on Orange stripes on both sides of body.both sides of body.

Each proleg has Each proleg has brownish or dark brownish or dark colored band on outer colored band on outer sides.sides.

True ArmywormTrue Armyworm

Primarily an early season (spring) Primarily an early season (spring) pest.pest.

Strong preference for grass crops:Strong preference for grass crops: Known to infest wheat and corn in LAKnown to infest wheat and corn in LA

Source of infestation:Source of infestation: Overwinters in larva stageOverwinters in larva stage MigrationMigration

Life cycle: egg to adult requires 41-66 Life cycle: egg to adult requires 41-66 days. Eggs laid in masses of 25 or days. Eggs laid in masses of 25 or moremore

True ArmywormTrue ArmywormObservations and Conventional Observations and Conventional

TrendsTrends Bigger problem in cool, wet springsBigger problem in cool, wet springs Prefers fields with lush, rank growth and Prefers fields with lush, rank growth and

lodging. Moth like to lay eggs in moist shady lodging. Moth like to lay eggs in moist shady areas.areas.

In LA, infestations usually develop in April.In LA, infestations usually develop in April. Feeds at night. During day it hides under soil or Feeds at night. During day it hides under soil or

under surface debri and thatch.under surface debri and thatch. Scout for pest during early am and late pm, or Scout for pest during early am and late pm, or

look for larvae on and under the ground surface.look for larvae on and under the ground surface. Feeds on foliage. Appears as notches on leaf Feeds on foliage. Appears as notches on leaf

margin, or in extreme cases complete margin, or in extreme cases complete defoliation.defoliation.

Frass appears as black, pepper-like droppings.Frass appears as black, pepper-like droppings. Feeding on the heads (beards) and/or clipped Feeding on the heads (beards) and/or clipped

headsheads

True ArmywormTrue Armyworm When to treat: 5 or more larvae per When to treat: 5 or more larvae per

square foot and foliage loss is square foot and foliage loss is occurring.occurring.

Protect crop/foliage until physiological Protect crop/foliage until physiological maturity (hard dough stage).maturity (hard dough stage).

Head clipping:Head clipping: Theory 1: Clip heads after defoliating Theory 1: Clip heads after defoliating leaves.leaves. Theory 2: Some years heads clipped Theory 2: Some years heads clipped and some years they are not.and some years they are not. Suggested threshold of 2-3% clippedSuggested threshold of 2-3% clipped heads.heads.

Stink BugsStink BugsRice Stink Bug and Southern Green Rice Stink Bug and Southern Green

Stink BugStink Bug Occasional pest, more Occasional pest, more

so in south LA.so in south LA. Damage developing Damage developing

seed grain with seed grain with piercing-sucking piercing-sucking mouthparts.mouthparts.

At milk stage or At milk stage or earlier (flowering): earlier (flowering): treat when 10% of treat when 10% of seed heads have stink seed heads have stink bugs.bugs.

At soft dough stage, At soft dough stage, treat when 25% of treat when 25% of seed heads have stink seed heads have stink bugs.bugs.

AphidsAphids

Yellow sugarcane aphid Greenbug Russian wheat aphid

English grain aphid Oat bird cherry aphid Corn leaf aphid

AphidsAphidsGeneral BiologyGeneral Biology

Generation – about a Generation – about a week from birth to week from birth to mature aphidmature aphid

Adult females give Adult females give birth to living young; birth to living young; 2-3 per day for 2-3 2-3 per day for 2-3 weeksweeks

Piercing-sucking Piercing-sucking mouthparts; remove mouthparts; remove plant juicesplant juices

Winged or winglessWinged or wingless Soft bodied insectsSoft bodied insects

IdentificationIdentification LegsLegs AntennaeAntennae Siphunculi Siphunculi

(cornicles)(cornicles)

AphidsAphidsPotential pests, but normally not a major Potential pests, but normally not a major

problem in LA.problem in LA.

Inject ToxinInject Toxin Russian wheat Russian wheat

aphid – does aphid – does notnot occur in LA.occur in LA.

Greenbug – Greenbug – usually does not usually does not develop high develop high populations.populations.

Yellow sugarcane Yellow sugarcane aphid – Not as aphid – Not as toxic to wheat as toxic to wheat as to sorghum.to sorghum.

Do Not Inject ToxinDo Not Inject Toxin Corn leaf aphidCorn leaf aphid Oat bird cherry aphidOat bird cherry aphid English grain aphid – English grain aphid –

clusters on grain clusters on grain heads.heads.

Transmit BYDVTransmit BYDV Corn leaf aphidCorn leaf aphid Oat bird cherry aphidOat bird cherry aphid English grain aphidEnglish grain aphid GreenbugGreenbug

Oat Bird Cherry AphidOat Bird Cherry Aphid Color ranges from Color ranges from

green to blackgreen to black Tips of siphunculi, legs Tips of siphunculi, legs

and antennae are and antennae are black.black.

Reddish-orange Reddish-orange colored patch on rear colored patch on rear of abdomenof abdomen

Direct feeding usually Direct feeding usually not damagingnot damaging

Corn Leaf AphidCorn Leaf Aphid

Blue green color; Blue green color; can appear blackcan appear black

Black siphunculi, Black siphunculi, legs and antennaelegs and antennae

More common on More common on grain sorghum grain sorghum than wheatthan wheat

Direct feeding Direct feeding usually not a usually not a problem.problem.

English Grain AphidEnglish Grain Aphid

Long, black Long, black siphunculisiphunculi

Black antennae that Black antennae that extend straight back extend straight back over the abdomen.over the abdomen.

Dark legs or leg Dark legs or leg bandsbands

Direct feeding can Direct feeding can cause damage; usually cause damage; usually in flowering/ early grain in flowering/ early grain formation.formation.

Dark hit areas in field Dark hit areas in field from flag leaf damage from flag leaf damage and fungal infected and fungal infected heads.heads.

Thresholds are available Thresholds are available in some states.in some states.

GreenbugGreenbug Light green with Light green with

dark green stripe dark green stripe down the backdown the back

Dark tips on Dark tips on siphunculi (tail siphunculi (tail pipes) and legspipes) and legs

Present in wheat Present in wheat all winter and can all winter and can reproduce at reproduce at temperatures lower temperatures lower than natural than natural enemies.enemies.

Injects toxin; Injects toxin; results in yellowish results in yellowish spot with dark spot with dark lesion; ultimately lesion; ultimately death.death.

Damaged areas first Damaged areas first appear as N appear as N deficiency/ moisture deficiency/ moisture stress.stress.

Yellow Sugarcane AphidYellow Sugarcane Aphid Long, oval, hairy body Long, oval, hairy body

shape.shape. Lemon yellow to mint Lemon yellow to mint

green color green color Siphunculi, legs and Siphunculi, legs and

antennae are light antennae are light colored.colored.

Injects toxin and can Injects toxin and can cause serious damage.cause serious damage.

More damaging to More damaging to grain sorghum than grain sorghum than wheat.wheat.

Russian Wheat AphidRussian Wheat Aphid

Present in 16 western states on wheat Present in 16 western states on wheat and barleyand barley

First US detection was in Muleshoe, First US detection was in Muleshoe, TX in 1986TX in 1986

Aphid MummiesAphid Mummies

Aphids that have Aphids that have been parasitized been parasitized by small wasps.by small wasps.

Greenbug Greenbug mummiesmummies

Hessian FlyHessian Fly Important pest of wheat, Important pest of wheat,

but rarely a problem in but rarely a problem in the deep south states.the deep south states.

Outbreaks in the Outbreaks in the southeast in 1984-1985 southeast in 1984-1985 and 1985-1986.and 1985-1986.

Outbreak in Alabama in Outbreak in Alabama in 1989.1989.

Detected in southwest Detected in southwest Alabama in 2006.Alabama in 2006.

Detected in collections Detected in collections taken from Louisiana in taken from Louisiana in 2000.2000.

Pupa (Flaxseed)

Larva (Maggot)

Insecticide Seed Insecticide Seed TreatmentsTreatments

Gaucho and Cruiser have wheat Gaucho and Cruiser have wheat labels.labels.

Labeled for aphid control and Labeled for aphid control and Hessian fly controlHessian fly control

No current LA data at this time to No current LA data at this time to support their use, but they will be support their use, but they will be looked at this year.looked at this year.

QuestionsQuestions