Green Peach Aphid (Kansas Canola)

Scouting time

Regular scouting is the best method to monitor the effectiveness of seed treatments during the fall. Use this scouting to assess the need for treating spring infestations. If populations are high from January through March, an insecticide treatment may be necessary. It is important to note that canola can recover from aphid infestations following timely insecticide applications.

Sampling method

1. Walk diagonally across the field and stop 10 times.
2. Check three plants at 10 stops (30 plants).
3. Count aphids on three consecutive plants.
4. Make sure to flip the leaves over and check, especially
leaves closest to the ground.
5. Note other spots with dead or dying plants.


Before flowering, canola can tolerate large numbers of aphids before an insecticide application is justified. It is important to delay insecticide use until the treatment threshold has been reached. Use of insecticides on very low aphid densities will result in net dollar losses. Delaying the first insecticide application reduces the likelihood that a second or third application will be needed.

a) If canola price is 0.30 ($/lb), then the treatment threshold is 50 – 100 aphids per plant.
b) If canola price is 0.25 ($/lb), then the treatment threshold is 60 - 120 aphids per plant.
c) If canola price is 0.20 ($/lb), then the treatment threshold is 70 – 140 aphids per plant.
d) If canola price is 0.15 ($/lb), then the treatment threshold is 80 – 160 aphids per plant.
e) If canola price is 0.10 ($/lb), then the treatment threshold is 90 – 180 aphids per plant.

Chemical control

Chemical Name


Seed Treatments



Poncho and Prosper


Dyna-Shield Imidacloprid


Helix Lite and Helix Xtra

Foliar Sprays



Annex, Bifenthrin, Capture, Discipline, Empower, Fanfare, Sniper and Tundra


Delta Gold


Lambda T, Silencer, Taiga Z and Warrior with Zeon Technology



methyl parathion

Chemnova Methyl

*Aphids are not specifically listed on label under canola, however some suppression of aphids can be expected based on usage in other crops. This web page was prepared to help producers manage insect populations with the best available methods proven practical under Kansas conditions. Pesticide label directions and restrictions are subject to change, and some may have changed since this publication was written. Kansas State University entomologists assume no responsibility for product performance, personal injury, property damage, or other types of loss resulting from the handling or use of the pesticides listed. Remember, it is illegal to use a pesticide in a manner that is inconsistent with the label. The user bears responsibility for correct use. Always read and follow label directions carefully.

Non-chemical controls

None listed.

Content authors


This content may be suitable for states other than Kansas.