2009 Canola Insect Control Update (pdf)

Canola Insects

Management of Insect and Mite Pests in Canola (pdf)

Scouting Canola for Diamondback Moth (pdf)

 

Major Insects seen in Oklahoma

• Southern cabbageworm
• Turnip aphid
• Cabbage aphid
• Harlequin bug
• Diamond back moth

 

Common Insects on Canola in Oklahoma

Green Peach & Turnip Aphids

 

Green peach and turnip aphids tend to feed on the underside of the canola leaves. Make sure you flip the leaves over and check, especially those leaves closest to the ground.

Sampling for Green Peach or Turnip Aphids in Winter Canola

Pattern:    Walk diagonally across field and stop 10 times

1. Check 3 plants at 10 stops (30 plants)
2. Count aphids on 3 consecutive plants (check under leaves!)
3. Note other spots with dead or dying plants

Action Thresholds:  For every aphid per plant 0.5 lb of seed is lost in a field; canola can handle large numbers of aphids before a costly insecticide is justified. It is important to delay insecticide use until aphids approach economic levels because:

• Use of insecticides on very low populations will result in net $ losses.
• Delaying the first insecticide application reduces the chance on needing a second or third application.

To prevent economic losses, manage aphids when:

$/lb		Aphids / Plant:
0.30		50-100
0.25		60-120
0.20		70-140
0.15		80-160
0.10		90-180

 

This information was provided by Dr. Kris Giles, Oklahoma State University, Entomology and Plant Pathology. For further information on identifying or controlling pest problems in your field contact your local OSU county extension office.

 

Cabbage Aphid Damage on Canola

 

 

Diamond Back Larve

 

Canola Insects

• Several insects species can damage winter canola, but not all of them are problems in Oklahoma. Some defoliate plants or attack buds or seed pods. Insect data is limited in the Plains.
• Major insects that have attacked canola in the Great Plains in the last 10 years are grasshoppers, cutworms and aphids.
• Grasshoppers can be a problem at seedling emergence.
• Canola is very palatable to cutworms. If wheat needs to be treated for cutworms then canola needs to be treated.
• As acreage of canola increase in the region concerns over insects will increase.

Other Canola Insects

• Other insects that attack canola re flea beetles, cabbage seedpod weevils, cabbage worms, loppers, armyworms, Diamondback moth larvae, cabbage root maggot larva and lygus bugs.
• Flea beetles: Attack coptyledons at emergence and produce shot holes. Generally not a problem unless planted very early.
• Cabbage seed pod weevil is attracted to the yellow color of the flowers and attack young seedpods.
• Cabbage worm, armyworms, diamondback moth larvae, and cutworms defoliate canola plants during the fall and spring. Damage is usually minor and yield loss minimal.
• Lygus bugs feed and lay eggs on canola during budding. Damage can include flower abortion and poor seed set with small shriveled seeds.
• Cabbage root Maggot Larva are small white, legless maggots that hatch in three to five days. Eat their way through canola roots, creating feeding tunnels. Could be a major concern in Nor-till Canola.
• Aphids ten to colonize the terminal bids late in the season. Yield Loss from aphid is generally not considered significant.

Careful consideration of insecticide applications should be made during flowering to limit exposure to pollinating insects.

Canola Insects - Not Common to Wheat

• White to cream colored masses appear on the underside of leaves. Raised green blisters form that turn white during wet weather.
• Major symptoms is swollen, twisted and distorted inflorescences called "stagheads" that become brown, hard and dry as they mature.
• Yield losses of 20% have been recorded.

 

Pests of Canola Seedlings

Flea Beetle

• Attack cotyledons at emergence and produces shot holes. Generally not a problem unless planted very early.
• 2 to 3 mm long,. black/bluish sheen, or black with two yellow stripes
• Damage - shot-holes in cotyledons and first leaves.
• Scout in fall when crop is in seedling stage.

 

 

Red Turnip Beetle

• 7mm long, red and black patches on the head, 3 black stripes running down the back.
• Damage - feeds on leaves; moves in from field edges.
• Scout field edges.

 

Cutworm

• When disturbed will curl up.
• Dark gray, yellowish pink stripes along back.
• Damage - leaf feeding.
• Scout in fall and spring.

 

Pests of Plants in Rosette to Pod Stage

Cabbage seed pod weevil is attracted to the yellow color of the flowers and attack young seedpods.

 

• Larvae are white and grub-like and feed on seeds in developing pods
• Damage - Larvae eat developing seeds, causing yield loss. Pods are susceptible to shattering and disease.
  
• Adult is gray, 3 to 4 mm long, with a prominent curved snout.
• Damage - feeding on flower buds causes bud-blasting.
• Scout from bud stage through flowering.

 

Foliage Feeders

Cabbage worm, armyworms, diamondback moth larvae, cutworms and other insects defoilate canola plants during the fall and spring. Damage is usually minor and yield loss minimal.

 

Armyworm

• Mature larvae pale brown to velvety black/brown, light brown head, orange stripe along each side.
• Damage - leaf, stem and pod feeding.
• Scout in spring to harvest.

Beet Armyworm

• Larvae are dark green then turn black as they mature, with two white stripes, on either side of the center line of the back.
• Damage - leaf, stem and pod feeding. Spin silk webs on the tops of plants.

Diamondback Larva

• Pale yellowish green larvae.
• Damage - mature larvae cause leaf, stem and pod stripping.

 

 

Alfalfa Looper

• Green/olive, with pale head, a light stripe down each side, and two light stripes along the back. Mature larvae have a swollen abdomen.
• Damage - leaf feeding, flower and pod clipping.

Cutworm

• When disturbed will curl up.
• Dark gray, yellowish pink stripes along back.
• Damage - leaf feeding.
• Scout in fall and spring.

Cabbageworm

• Larvae are green with a velvety texture, faint yellow stripe down the back.
• Feed on leaves, but do not cause economic losses.

 

 

Grasshoppers

• Adults are large with large legs and wings.
• Damage - nymphs and adults feed on leaves, stems and pods.
• Scout May through July, especially along edges of the field.

Aphids

• Aphids frequently cove the entire top part of the plant.
• Green or black, winged or wingless.
• Do not usually cause economic losses.

Lygus Bug

• Pale green to red/brown with a "v" mark one-third of the way down the back. Young nymphs are pale green in color and resemble aphids.
• Damage - feed on leaves, stems, flowers, and pods. Cause flower blasting and shriveled seeds.
• Scout from pre-bud until seeds within pod become firm.

 

 

Painted Lady Larva

• Mature larvae are black with spikes along the back and yellow stripes along the side.
• Damage - feed on leaves. Do not cause economic losses.

Thrips

• Tiny black specks in a sweep net. Under a magnification are black, linear - shaped body.
• Damage - feeding causes twisted pods.
• Do not usually cause economic loss.

Canola Insects - Labeled Insecticides

Capture 2 EC - 2.1 to 2.6 fluid oz per acre

• Diamondback moths
• Loopes
• Armyworms
• Aphids
• Cutworms
• Flea Beetles
• Flea hopper

Warrior T 1 EC - 1.9 to 3.84 fluid oz per acre

• Diamondback moths
• Loopes
• Armyworms
• Aphids
• Cutworms
• Flea Beetles
• Lygus bug
• Seed pod weevil
• Grasshoppers

Karate Z 08 Label (pdf)

 

Confrim, Ethyl and Methyl Parathion

Crymax, Deliver, Dipel, Lepionox, XenTari-Bio Insecticide

• Lepidoptera (armyworms, Diamondback moth, cabbageworm, loopers)

Ecozin - Botanical Insecticide (Azadirachtin)

Seed treatments Helix and Gaucho.

Labels in effect in 2004.

Beneficial Insects