Major Pest Report- Ajed

7/29/2019 Major Pest Report- Ajed

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MAJOR INSECT PESTS OF CORN

INSECT PESTDESCRIPTION OF THE

DESTRUCTIVE STAGELIFE HISTORY NATURE OF DAMAGE ALTERNATIVE HOST CONTROL MEASURES

1.Common Name:

black cutworm

scientific

Name:Agrotisipsilon (Hufnagel)

(Insecta:

Lepidoptera:

Noctuidae)

Larvae are greyish-black with a

paler underside and no distinct

markings on their bodies.

Mature larvae are about 3.5

cm (1 1/4 in.) long and hide inthe soil during the day. They

can be found near freshly cut

plants, under soil clumps or

along a poorly closed seed

furrow.

Life History: Cutworm moths do

not over-winter in Ontario but are

carried in from the south on

strong southerly weather systems.

The heaviest immigration occursfrom April to May but may occur

as early as March. Cutworms are

therefore more frequent in fields

with green cover early in the

spring. There are several

generations per year, however,

only the first generation causes

economic damage in corn. Warm,

clear, calm nights in early spring

are ideal for moths to lay eggs.

Egg: The egg is white in color

initially, but turns brown with age.

It measures 0.43 to 0.50 mm high

and 0.51 to 0.58 mm wide and is

nearly spherical in shape, with a

slightly flattened base. The egg

bears 35 to 40 ribs that radiate

from the apex; the ribs are

alternately long and short. The

eggs normally are deposited in

clusters on foliage. Females may

deposit 1200 to 1900 eggs.

Duration of the egg stage is three

to six days.

Larva: There are five to nine

instars, with a total of six to seven

instars most common.

In appearance, the larva is rather

uniformly colored on the dorsal

and lateral surfaces, ranging from

light gray or gray-brown to nearly

black. The head is brownish with

Gaps in the stand

Plants are stunted orwilted

Plants are cut off ator below soil level

Leaf tissue feeding

Feeding holes areragged

Bluegrass, Poa pratensis;

Burled dock,Rumex

crispus;

Lambsquarters, Chenopod

ium album; Yellowrocket, Barbarea vulgaris;

and Redroot

pigweed,Amaranthus

retroflexus.

Survey and Trapping.

Adult populations can

be monitored with

both blacklight and sex

pheromone traps.

Chemical. Cutworms

are most active in the

evening, so

insecticides applied at

night/evening are

more effective. Foliar

insecticide application

to mature larvae

(larger than 2.5 cm or

1 in.) is not

recommended sincemost of the damage

has occurred and

control may be

inadequate.Lateral view of the larva of a blackcutworm, Agrotis ipsilon (Hufnagel).Photograph by John L. Capinera,

University of Florida

Damage by black cutworm


2/13

numerous dark spots. Larvae

usually remain on the plant until

the fourth instar, when they

become photo-negative and hide

in the soil during the daylight

hours. In these latter instars they

also tend to sever plants at the soil

surface, pulling the plant tissue

belowground. Larvae tend to becannibalistic.

Pupa: Pupation occurs

belowground at a depth of 3 to 12

cm. The pupa is 17 to 22 mm long

and 5 to 6 mm wide, and dark

brown. Duration of the pupal

stage is normally 12 to 20 days.

Adult: The adult is fairly large in

size, with a wingspan of 40 to 55mm. The forewing, especially the

proximal two-thirds, is uniformly

dark brown. The distal area is

marked with a lighter irregular

band, and a small but distinct

black dash extends distally from

the bean-shaped wing spot. The

hind wings are whitish to gray, and

the veins marked with darker

scales.

Adult black cutworm,Agrotis

ipsilon (Hufnagel). Photograph by John

L. Capinera, University of Florida.


3/13

2. Corn Flea Beetle

(Chaetocnema

pulicaria)

ColeopteraChrysomelidae

Desrtructive stage:

Adult

Life History: This pest over-winters

as adults at the base of grasses. In

the early spring, beetles emerge,

and mated females then lay their

eggs in the soil close to the base of

corn plants. Within 6 days, eggs

hatch into larvae, which then

pupate. Within 14 days, the adult

beetle emerges from the soil.There are three to four

overlapping generations per year.

Only those generations occurring

from early-May to late-June,

during corn emergence, are

considered a potential problem

Leaf tissue feeding Feeding tracks running

parallel to leaf veins on

upper surface of leaf

Injures by removingleaf tissue and

transmitting pathogenic

bacteria which is

Erwinia stewartii

(=Pantoea stewartii).

Common in most of

all crops suchas

Sorghum, other

weeds and grasses.

Use

insecticide seed

treatments on

susceptible hybrids

and inbreds, and for

those fields with a

history of flea beetle

activity.

Avoid earlyplanting dates for

varieties susceptible to

Stewart's wilt. Plant

fields with a history of

Stewart's wilt to

resistant hybrids.

Additional

foliar sprays may be

necessary for seed

corn and susceptible

varieties if populations

are very high.

3.Potato Stem Borer

(Hydraecia micacea)

Lepidoptera:

Noctuoidea

DESTRUCTIVE STAGE:

LARVA Life History: This pest is moresevere in the eastern counties, butinfestations occur throughout the

province. There is one generation

per year. This pest over-winters as

eggs on grasses. Eggs are laid in

two or three parallel rows under

the leaf sheath. These hatch in late

April, and the small larvae initially

bore into the stalks of grass plants.

By late May, the larvae outgrow

the grass stalks and move to

Gaps in the stand

Seed is fed upon orhollowed out

Plants are stunted orwilted

Stalk damage

Tunneling within thestalk

Barnyardgrass,Echino

choa crus-galli;

Beggarticks, Bidens s

pp.;

Cocklebur,Xanthium

spp.;

Dock, Rumexspp.;

Jimsonweed, Datura

spp.; panic

grass, Panicum spp.;

Pigweed,Amaranthu

Management

Strategies:

There is no effective

or economic

chemical control for

this insect, since the

borer remains inside

the plant where it is

protected.

Good weed control,

especially of grassy

Adult Corn Flee Beetle

Image of injured leaf tissue


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nearby thicker stalk crops such as

corn. These larvae continue to

feed until late June, pupate and

emerge as adults in late July.

EGG:Egg semispherical, yellowish-

white, later pinkish. Diameter of

eggs 0.7-0.8 mm, height 0.4 mm.

LARVA:

Caterpillars light yellow to fleshy-

red with reddish stripe along

dorsum. Head red, without

pattern; thoracic and anal shields

and plates bearing setae, brown.

Spiracles black. Caterpillars 40-45

mm long. Pupae yellow-brown, 17-

25 mm in length; cremaster with 2

processes

PUPA:

Pupae yellow-brown, 17-25

mm in length; cremaster with 2

processes.

ADULT:

Forewings of the moth grayish-

yellow or dark brown-gray, with

reddish tint (wingspan 28-40 mm).

Transversal lines brown. A part of

the wing between the lines isdarker than the rest, especially

behind round and reniform spots

having background wing color.

Hind wings grayish-yellow or

pinkish-yellow, with a dark stripe

in distal third of wing. Females

usually larger than males

s spp.;

Smartweed, Polygon

umspp.; and others.

weeds, is effective in

reducing the risk of

damage next year.

Fall plowing or

burndown can

reduce the number

of over-wintering

eggs. Parasitic wasps

generally keep this

pest below

economically

damaging levels.

Image of Tunneling within

the stalk


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4.Common Name:European corn borer

Scientific

Name: Ostrinia

nubilalis (Hbner)

(Insecta: Lepidoptera:

Pyralidae)

European corn borer larvae

are cream to pink with black

heads and two black spots

per abdominal segment.

Stalk rots can be carried in

by larvae.

- Early-season larvae feed onleaves, creating small pinholes

and eventually migrate into the

whorl of the plant and attackthe enclosed tassel.

Life History: There are two

distinct strains in Ontario.

South of a line from Sarnia to

Simcoe, a bivoltine strain can

undergo multiple generations

(typically two), depending on

the length of the season. North

of this line, a univoltine strainhas only one generation per

year. There is a band of overlap

for these two strains, about 50-

80 km wide along this line.

Egg: Eggs are deposited in

irregular clusters of about 15 to

20. The eggs are oval,

flattened, and creamy white in

color, usually with an iridescentappearance. The eggs darken

to a beige or orangish tan color

with age. Eggs normally are

deposited on the underside of

leaves, and overlap like

shingles on a roof or fish scales.

Eggs measure about 1.0 mm in

length and 0.75 m in width. The

developmental threshold for

eggs is about 15C. Eggs hatch

in four to nine days.

Leaf tissue feeding

Pinholes or round,symmetrical holes

Stalk damage

Tunneling within thestalk

Tunneling within the stalk

Grasses and other

field crops

Biological control.Natural enemies:

Lydella

thompsoniGHerting

(Diptera:

Tachinidae), a

parasitiod of the

European corn borer

Eriborus

terebrans Gravenhor

st (Hymenoptera:

Ichneumonidae)

Insecticides.Cultural

practices. Destruction

of stalks, the

overwintering site of

larvae,

Mature larva of the European corn

borer, Ostrinia nubilalis (Hubner).

Photograph by John L. Capinera,

University of Florida


6/13

Larva: Larvae tend to be

light brown or pinkish gray in

color dorsally, with a brown

to black head capsule and a

yellowish brown thoracic

plate. The body is marked

with round dark spots on

each body segment.

Larvae normally display six

instars.

PUPA: The pupa is normally

yellowish brown in color.

The pupa measures 13 to 14

mm in length and 2 to 2.5

mm in width in males and 16

to 17 mm in length and 3.5

to 4 mm in width in females.

The tip of the abdomen

bears five to eight recurved

spines that are used to

anchor the pupa to its

cocoon.

- Duration of the pupal stage

under field conditions isusually about 12 days.

Adult: The moths are fairly small,

with males measuring 20 to 26

mm in wingspan, and females 25

to 34 mm. Female moths are pale

yellow to light brown in color, with

both the forewing and hind wing

crossed by dark zigzag lines and

bearing pale, often yellowish,

patches. The male is darker incolor, usually pale brown or


7/13

grayish brown, but also with dark

zigzag lines and yellowish patches.

Moths are most active during the

first three to five hours of

darkness

5.Corn Rootworm

(Diabrotica virgiferaColeoptera

Chrysomelidae

DESTRUCTIVE STAGE:

LARVA ADULT

Life history:

The Western cornrootworm, Diabrotica virgifera

virgifera is a serious pest of maize

(Zea mays). It originated in North

America but was discovered in

Europe in 1992 near Belgrade

(former Yugoslavia). Outbreaks

have been confirmed in several EU

member states. It was first

reported in the UK in 2003 on

maize near London Heathrow and

Gatwick airports. Statutory actionwas required around affected

locations, but these have been

lifted in the absence of findings

since 2007.

LARVA:

The CRW larvae go through three

instars, or developmental stages,

that each lasts seven to ten days.

The first instar is less than 1/8 inch

in length. By the third instar larva

can measure up to 1/2 inch in

length

PUPA:

After the larvae have completed

the three developmental stages

(instars), they will pupate in the

soil. The pupal stage is a dormant

stage when no feeding takes place

ADULT:

adults begin to emerge in July and

may continue for one month. Male

beetles emerge prior to females.

After the beetles emerge from thepupal case, they dig their way up

to the surface of the soil. Once the

Stalk damage

Stalk "goosenecked"

Damage in Dry Edible

Beans: Damage begins as

leaf feeding, but once the

larvae get bigger, they will

move to feed on and into

the pods and seeds

Western Corn Rootworm beetle

(Marlin E. Rice, ISU)

Surghum, grasses

and oither crops

Management

Strategies: Crop rotation

is the best

strategy and

is superior to

insecticides

for reducing

rootworm

populations.

Continuous

corn fields

produce up to4 million

beetles per

hectare.


8/13

adults have exited the soil they

will instinctively crawl upward,

often on a corn plant where they

will begin feeding

6. Common Name:European corn borer

Scientific

Name: Ostrinia

nubilalis (Hbner)(Insecta: Lepidoptera:

Pyralidae)

Young larvae the destructive

stage of WBC that feed on

the tassels and silks until

they are large enough to

tunnel into the ear and feed

extensively on the kernels.

In whorl-stage corn, larvae

will feed on the developing

pollen.

EGG:

Eggs are laid in masses of 5-200

eggs. WBC eggs are the size of a

pin head, pearly white when first

laid and are shaped like tinycantaloupe . As the eggs mature,

they turn tan and then purple in

colour. Eggs hatch in about 5-7

days.

Western bean cutworm eggs are

shaped like cantaloupe and are white

when first laid. They turn purple just

before the larvae hatch.

Larva:Larvae hatch in late May or

early June and begin to feed on

corn roots. Newly hatched

larvae are small, less than

1/8 inch long, white worms.

Corn rootworms go throughthree larval instars, pupate in

the soil, and emerge as adults

in July and August. There is one

generation per year. Larvae

have brown heads and a brown

marking on the top of the last

abdominal segment, giving

them a double-headed

appearance. Larvae have three

pairs of legs, but these are not

usually visible without

magnification. After feeding for

Ear damage

entry hole on sideof ear and feeding

Silks clippedTassel damage

Tassels are fed on

Biological control

Several natural

enemies feed on egg

masses and young

larvae, including ladybeetles, spiders and

others.

Heavy raincan reduce

young larvae

survival.

Chemical control:

Foliarinsecticide

timing is

critical. Timing of

application

must

coincide

with egg

hatch when

young larvae

are feeding.


9/13

several weeks, the larvae dig a

cell in the soil and molt into the

pupal stage.

PUPA:

The pupal stage is white and

has the basic shape of the adultADULT:

Adult rootworms are about

1/4 inch long. Western corn

rootworms are yellowish with a

black stripe on each wing cover.

7. Common Name: fall

armyworm

Scientific

Name: Spodoptera

frugiperda (J.E.

Smith) (Insecta:

Lepidoptera:

Noctuidae)

DESTRUCTIVE STAGE:

LARVA

Life History: Fall armyworm adult

moths migrate from the southern

U.S. and show up later in the

season, when the corn is fully

grown. This insect cannot over-

winter in areas where the ground

freezes.

Egg: The egg is dome shaped; the

base is flattened and the eggcurves upward to a broadly

rounded point at the apex. The

egg measures about 0.4 mm in

diameter and 0.3 m in height. The

number of eggs per mass varies

considerably but is often 100 to

200, and total egg production per

female averages about 1500 with

a maximum of over 2000. The eggs

are sometimes deposited in layers,

but most eggs are spread over a

single layer attached to foliage.The female also deposits a layer of

Leaf tissue feeding

Feeding holes areragged

Ear damage

entry hole on side ofear and feeding

Tassel damage

Tassels are fed on

Corn cob damage caused by the fall

armyworm, Spodoptera

frugiperda (J.E. Smith). Photograph by

USDA

Variety selection

There are no

commercial non-

transgenic rootworm-

resistant corn

varieties.

Several hybrid

corn traits may reduce

damage from larvalrootworm feeding by

increasing stalk

strength and root

mass size.

Early planting Insecticides Crop rotation

Other crops sometimes

injured are apple, grape,

orange, papaya, peach,

strawberry and a number

of flowers. Weeds known

to serve as hosts include

bentgrass,Agrostis sp.;

crabgrass, Digitaria spp.;

Johnson grass, Sorghum

halepense; morningglory,Ipomoea spp.;

nutsedge, Cyperus spp.;

pigweed, Amaranthus spp

.; and sandspur, Cenchrus

tribuloides

Adult European corn borer
http://en.wikipedia.org/wiki/Hybrid_cornhttp://en.wikipedia.org/wiki/Hybrid_cornhttp://en.wikipedia.org/wiki/Hybrid_cornhttp://en.wikipedia.org/wiki/Hybrid_corn


10/13

grayish scales between the eggs

and over the egg mass, imparting

a furry or moldy appearance.

Duration of the egg stage is only

two to three days during the

summer months.

Larva: There usually are six instars

in fall armyworm. Head capsule

widths are about 0.35, 0.45, 0.75,1.3, 2.0, and 2.6 mm, respectively,

for instars 1-6. Larvae attain

lengths of about 1.7, 3.5, 6.4, 10.0,

17.2, and 34.2 mm, respectively,

during these instars. Young larvae

are greenish with a black head, the

head turning orangish in the

second instar.

Pupa: Pupation normally takes

place in the soil, at a depth 2 to 8

cm. The larva constructs a loose

cocoon, oval in shape and 20 to 30

mm in length, by tying together

particles of soil with silk. If the soil

is too hard, larvae may web

together leaf debris and other

material to form a cocoon on the

soil surface. The pupa is reddish

brown in color, and measures 14

to 18 mm in length and about 4.5

mm in width.

Adult: The moths have a wingspan

of 32 to 40 mm. In the male moth,the forewing generally is shaded

gray and brown, with triangular

white spots at the tip and near the

center of the wing.


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Corn Leaf Aphid

(Rhopalosiphum

maidis)

HYMENOPTERA

Aphididae

Life History: This pest does not

over-winter in Ontario but arrives

each year on air currents from the

south where crops are more

advanced. Initial spring migrants

feed on cereals, until corn

becomes attractive. Migrating

populations are comprised of

winged females only. Once theysettle, these females reproduce

without mating and give birth to

live wingless nymphs. Both winged

and wingless generations of adults

develop, depending on the

nutrient quality of the plant.

Winged aphids then fly to nearby

corn fields and enter the whorl.

There are several generations per

year.

Life Cycle: The first spring adultsare winged females which fly in

search of suitable host plants.

Shortly thereafter, they give birth

to live nymphs which usually

develop into wingless females.

Under favorable conditions, more

winged females develop and

migrate. Males are rarely found

but females continue to reproduce

without mating. No egg stage is

known. Reproduction slows downin winter and summer and is most

rapid during cool weather.

Therefore, corn leaf aphids tend to

be a problem on winter grains in

spring and on late-planted corn in

fall.

Tassel damage

Tassels discoloured or sticky barley, sorghum

It also infests many

other wild and

cultivated grasses

Management

Strategies: Chemical

control is warranted

only if the natural

enemies and parasites

of the corn leaf aphids

are not present and

aphid densities are

above threshold.There are several

natural enemies that

exist and are quite

effective at controlling

corn leaf aphids. These

include lady beetle

adults and larvae,

lacewing adults and

larvae, and a few

parasitic wasps.

Chemical control will

kill natural enemiesand may lead to a

resurgence of the

aphid population.

Corn leaf aphids clustered

on corn ear. Tassels and silks

may become coated with

honeydew, reducing

pollination success.


12/13

Seedcorn Maggot

Delia platura

(Meigen)

Order: Diptera,

Family:

Anthomyiidae,

EGG:

The eggs are white, oblong

and about 0.9 mm in length.

LARVA:

The larvae are less than 1 mmin the first instar to 7 mm inthe third instar and tend to

occur in clusters at the base of

the plant or feeding inside ofthe root stem.

PUPA:

The puparium is 4-5 mm long

and is light reddish brown.

ADULT:

Adult: The adult flies are small

(4-5 mm long), grayish brown

and males have gray

stripes on the thorax. Theabdomen tends to be smaller

than what you observe on

houseflies, relative to the

overall body size.

Damage to Crop: The two

primary ways that

seedcorn maggot damages

crops is through reduction

of seedling stands and

contamination of the crop

later in the season. Mid- to

late season stand loss

caused by seedcorn

maggot has not been

observed, just secondary

invasion of the crop after

some other factor damages

the crop. Pupae can be

attached to harvested

portions of root crops,

from which adult flies can

emerge in fresh pack

stands in markets.

barley, sorghum

It also infests many

other wild and

cultivated grasses

Management:

The standard

treatment for

control of this pest is

to treat

preventatively with

pre-plant, in-furrow

insecticides

REFERENCES:

Department of Entomology. 2013. The European Corn Borer. Accessed from www.ent.iastate.edu/pest/cornborer/on September 7, 2013

Capinera, L. J. and kalisch J. et. Al..2000. FEATURED CREATURES. Accessed from entnemdept.ufl.edu/creatures/field/e_corn_borer.htm_on September 7, 2013.

Chaetocnema pulicaria accessed from http://en.wikipedia.org/wiki/Chaetocnema_pulicariaon September 8, 2013

Western corn rootworm accessed from http://en.wikipedia.org/wiki/Western_corn_rootwormon September 9, 2013

Sparks, Jr. A. and Riley D. G. Seedcorn Maggot. Accessed from http://www.ent.uga.edu/veg/colecrops/seedcornmag.htm on September 9, 2013
http://www.ent.iastate.edu/pest/cornborer/http://en.wikipedia.org/wiki/Chaetocnema_pulicariahttp://en.wikipedia.org/wiki/Western_corn_rootwormhttp://en.wikipedia.org/wiki/Western_corn_rootwormhttp://en.wikipedia.org/wiki/Chaetocnema_pulicariahttp://www.ent.iastate.edu/pest/cornborer/


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Major Pest Report- Ajed