Canola and Mustard XVI-6

Cabbage Aphids

Sue Blodgett & Greg Johnson

Aphid

Several species of aphids may infest canola and mustard crops including cabbage aphid, green peach aphid (GPA) and turnip aphid.

Identification (and Life cycle/seasonal history)

The cabbage aphid, the most common damaging species, is a small blue-gray colored aphid with short cornicles and covered with a white waxy secretions.  Dense colonies are formed around the youngest leaves and flowering plant parts.  Green peach aphid is pale green to yellow in color with long cornicles or tailpipes but lacks the waxy coating of the cabbage aphid Green peach aphid is more commonly found on seedlings, young plants and lower leaves of older plants.  In both aphid species females give birth to live young all year without mating. As aphid populations build up and become crowded winged adults are produced which disperse to begin new colonies. There are multiple overlapping generations of aphids within a season.

Plant Response and Damage

High populations can cause plant stunting, distortion, and discoloration at any growth stage.  Feeding by cabbage aphids can stop terminal growth leading to a reduction in plant size and yield.  Damage may be localized within a field and may be of little consequence if infestations occur after pod formation is completed. 

Management Approaches

Sampling

There are no established treatment thresholds for aphids on canola.  Check for aphid populations regularly.  Aphids tend to be the most abundant on upwind field edges so check these areas first.  If not aphids are found along field edges additional samples are not usually needed.  Aphid populations are often clumped within a field. GPA are usually found on the undersides of the oldest leaves.  Presence of natural enemies especially ladybird beetles can indicate that aphids are present.

Cultural Control

Eliminating volunteer and mustard family weeds from the field border.    

Biological Control

Aphids are attacked by a wide range of natural enemies including ladybird beetle adults and larvae, lacewing larvae, syrphid fly larvae, damsel bugs and minute pirate bugs.  Parasitic wasps are also important in long-term control of aphids.  However, natural enemy populations typically lag behind rapidly expanding aphid populations and contribute to long-term control but are often insufficient to prevent economic damage by a rapidly increasing population.

Chemical Control

In most cases spraying is not economical.  If the crop was planted late and the plants are still setting pods and if natural enemies such as ladybugs and parasites are not present, treatment may be warranted.

Check SpinTor, GF 120

Product List for Cabbage Aphids

Pesticide	Product/Acre	Preharvest Interval, Remarks
Capture 2EC^R,1	2.1 – 2.6 fl oz	35 days. 12 hr REI.  Do not apply more than 5.12 oz /A /season. Do not make applications less than 14 days apart.  See label for minimum gallonage.
Imidacloprid	12.8-32 oz/cwt (Gaucho 480)	12 hr REI. Seed treatment.  Applied by commercial seed treaters or as an end-use on farm treatment.
Helix XTra	23 fl oz/cwt	Seed treatment
Proaxis^R,1,2	3.84 oz	7 days, 24 hr REI. Do not apply more than 0.72pt/A/season. See seasonal use rates for gamma and lambda cyhalothrin.
Lambda-cyhaolthrin^R,1,2	3.84 oz (Warrior with Zeon) 3.84 oz (Lambda T)	7 days, 24 hr REI. Avoid application when bees actively foraging by applying early morning or evening. Do not apply more than 0.72 pt/A /yr. See seasonal use rates for gamma and lambda cyhalothrin.
Pyrethrins^1	2 – 16 oz (Evergreen EC 60-6) 4.5 – 18 oz (Pyganic EC 5.0)	0 Day, 12 hr REI .  No less than 2 GPA by air or 10 GPA by ground.  Buffer spray to pH 5.5 – 7.0.
^1Label allows chemigation, ^2 Generic active ingredient, several formulations available, see labels for rates ^R Restricted use pesticide
The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana. Criticism of products or equipment not listed is neither implied nor intended. Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies. State rules and regulations and special pesticide use allowances may vary from state to state: contact your State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality.

Categories: Canola, Mustard, Insects, Cabbage aphids

Date: 06/06/2006