Watch out for GRASSHOPPERS!

Amy J. Dreves, Nicole Anderson, and Clare Sullivan | OSU-Crop and Soil Science Department 9-16-2016

Clear-winged and Redlegged

Grasshoppers (short-horned, family Acrididae)

arrived in the Willamette Valley in large numbers

in Aug -Sept 2016. Two species have been

identified in agricultural fields. Clear-winged

grasshoppers have been prevalent in the south-

Valley and isolated cases of redlegged

grasshoppers in the mid-Valley.

Physical Characteristics:

*Clear-winged grasshopper (Camnula pellucida)

Small species with mottled leathery forewings,

transparent hindwings. (Fig 1 & 2)

*Redlegged grasshopper (Melanoplus femurrubrum)

Overall yellowish coloring on belly, strong banding on

the abdomen, herring-bone pattern on the hind

femur, reddish hind tibiae, and only faint spotting on

the tegmina (front wings). (Fig 3)

Documented HOSTS… clover, tall

fescue, orchardgrass, perennial ryegrass, small

grains, vegetables, pastures, bromes.

Damage. Look for notching, stripping,

chewing holes on any and all plants; damage

similar to armyworms and cutworm chewing.

Life Cycle. These species have overlapping

generations; eggs are laid in fall; eggs overwinter

in protective tubular pods under the soil and

hatch in spring. Both grasshoppers can fly which

allows them to quickly disperse and find new

habitats.

Estimating numbers in fields

When scouting, first check for numbers of

grasshoppers per square yard (7-12) and the

number of young grasshoppers (Fig 5). Scout

field borders and walk through a field to

estimate the number of grasshoppers per square

yard as they jump in front of you. A yard

measuring stick can help visualize a square yard,

just above the crop.

Fig 1-clear-winged

Fig 2- clear-winged adult grasshopper

Fig 3. Redlegged grasshopper

Fig 4. Damage in white clover, 2016

Management Options

Many insecticides (see below) have activity on

grasshoppers. However, they are most effective

against young grasshoppers. Nymphs are

wingless and are found hopping on the ground

instead of flying. Grasshoppers are active during

the day and rest on the tops or within grasses

and weedy areas.

Chemical Control

Fig. 5. Young grasshoppers have short wing pads,

so can’t fly, only hop or crawl. The youth pass

through 5-6 instars (stages), during which they

feed, molt their skins before turning into a

mature grasshopper with wings. The winged

grasshoppers will lay eggs in the fall.

References

Univ. of Nebraska Grasshopper Identification guide

http://extensionpublications.unl.edu/assets/pdf/ec15

69.pdf

A key to the grasshoppers of North America can be

found at Grasshoppers of the Western United States

Edition 3:

http://keys.lucidcentral.org/keys/v3/grasshopperE3/

Media/frmsetRLGH.htm

Cultural Practices

Tillage in late fall can destroy grasshopper egg

pods, but is not a means to control feeding

grasshoppers.

Strips of green foliage (Trap Strips) have been

used to attract grasshoppers to a small area

where they can be more easily treated.

Environmental Conditions

If warm spring temperatures, premature

hatching of eggs can result in heavy mortality.

Biological Agents

Birds will eat grasshoppers.

Diseases (e.g., Nosema, fungus, bacteria)

can keep populations down.

Eggs can die from mites, parasitic wasps and

flies.

Estimated Threshold: 7-12 GH per square yard

Some pesticides listed for grasshopper control:

cyfluthrin (Baythroid XL)

zeta-cypermethrin (Mustang MAX)

bifenthrin (Brigade 2EC and WSB)

chlorpyrifos (Lorsban)

carbaryl (eg. Sevin)

organophosphate (Malathion)

lambda-cyhalothrin (Warrior)

*See the PNW Insect Management Handbook for

current insecticide registrations per crop type

Fig 5

Females lay eggs in pods in soil in late fall.

ADULTS feed,

mate, and lay eggs

adult

nymph

eggs

Apr-May Jun-July Aug-Sept Oct-Nov WINTER

NYMPHS feed

Eggs

laid

winter

stage

ADULTS feed,

mate, and lay eggs

Treat

Eggs

Dreves 2016