Agronomy Update August 2024
Aphid Control in Canola
The warmer weather is causing a rise in aphid numbers. What do we do about them?
Many growers have moved away from using broad spectrum insecticides because they control both the pests and the beneficial insects. Maintaining and protecting beneficial insects is a valuable practice. It is like a double knock in weed control:
- Apply an aphicide like the products tabled below. They will provide reasonable control of the aphid population.
- The beneficial insects remaining will work to keep the population of aphids low and prevent another blow out.
Refer to this guide for The Beneficials Chemical Toxicity Table.
The common aphids in canola are;
- Turnip aphid Lipaphis erysimi
- Cabbage aphid Brevicoryne brassicae
- Green peach aphid Myzus persicae
Key Points:
- Early detection: Regular monitoring of crops is crucial for timely intervention.
- Understand aphid species: Different aphid species have varying sensitivities to insecticides.
- Rotate insecticides: Using insecticides with different modes of action helps prevent resistance development. Resistance is becoming common in some aphid species in some regions. Cesar Australia research has found that > 90% of all green peach aphid populations collected from canola crops across Australia are highly resistant to synthetic pyrethroids (e.g. alpha-cypermethrin) and carbamates (e.g. pirimicarb). Refer to your Agronomist.
- Follow label instructions: Adhere to recommended rates, timing, WHP and safety precautions.
- Thorough coverage: Ensure complete coverage of the crop during application. Adjust water rates to the crop stage.
- Bees: Ensure you adhere to label guidelines on bees and notify beekeepers in your area if you intend to spray.
Control Thresholds
In general, aphids should be sprayed when 20% of plants are infested with colonies of aphids. This may vary between regions and seasons. Local advice and experience should be used. The threshold is a range and needs to be determined by crop yield potential, weather conditions (rain may reduce numbers), crop conditions and aphid population dynamics. Crops that are not moisture-stressed have a greater ability to compensate for aphid damage and can tolerate higher infestations than moisture-stressed plants before yield loss occurs – Cesar Australia
Aphid Control in Canola – Options Popular with Agronomists
| Product | Versys | Pirimicarb | Transform | MainMan |
| Active | 100g/L AFIDOPYROPEN | 500 g/kg PIRIMICARB | 500 g/kg SULFOXAFLOR | 500 g/kg FLONICAMID |
| Mode of Action | 9D | 1A | 4C | 29 |
| Aphids on Label | Green peach aphid, Cabbage aphid, Aphids (Aphis spp) | Cabbage Aphid, Green Peach Aphid | Aphids including (Russian wheat aphid, cabbage aphid, green peach aphid) | Green peach aphid, cabbage aphid & turnip aphid. |
| Rate | 50 ml/ha + 0.2% Hasten | 500g – 1kg / ha + wetter | 50 – 100g + wetter | 100 g/ha + wetter |
| Crop Stage | DO NOT apply after the end of flowering (BBCH 69) | No later than 14 days before harvest | No later than 14 days before harvest | Up to BBCH 69 end of flowering |
| Translaminar (control on both sides of leaf) | Yes | No | Yes | Yes |
| Residual Control | Up to 21 days | |||
| Ground Rig water Rate | 100L/ha | 30-100L/ha | 50-100L/ha | 75 – 100L/ha |
| Aerial Water Rate | 50L/ha | 20-50L/ha | 30L/ha | |
| WHP | Grazing 7 days. Harvest N/A | 14 days | 14 days | Grazing 21 days. Harvest N/A |
| Temperature Requirements | Best results when over 20°C | 5 – 35°C | ||
| Beneficials | Low Mortality | Med – High Mortality | Low – High Mortality | Low Mortality |
| Bee Statement | Lower Risk | Lower Risk | Highly Toxic to Bees. Do not apply while bees are foraging | Soft on Honeybees |
| Bees | Even if a product is safer to bees. Do Not spray when bees are foraging | |||
| Other Crops | Wheat & Barley | Cereals, Lupins, Vetch | Cereals, forage brassicas | – |
