The green bridge from summer rains this year has ramped up populations of aphids, especially green peach aphids, in canola crops, and moisture stress is compounding the effects of feeding damage in many areas. Since the beginning of the season the PestFax team has received eight cabbage aphid reports, 10 turnip aphid reports and 26 green peach aphid reports, some of which were reports from multiple crops. At this time the PestFax team has not received any reports this season of aphids in cereal or pulse crops.
Canola aphid reports this week
Dan Taylor (DKT Rural Agencies) has found cabbage aphids in IH51 canola near Cunderdin. The canola plants are at stem elongation. 10-30% of the crop was estimated to have cabbage aphid infestation with plant death occurring in the worst patches.
Jessica Smith (DKT Rural Agencies) has found green peach aphids (GPA) on Bonito canola near Kellerberrin. The canola had eight true leaves or more. Vegetable weevil larvae were also found in patches in this paddock. Jessica commented that she was finding more hot spots throughout Kellerberrin now on late germinating drought stressed canola plants.
Faan Carlse (Landmark) has found GPAs on 2-4 leaf canola near Narrogin. The aphids were clustering around the new leaf and growing point.
Crop protection officer Jolie Delroy (DAFWA) has reported finding GPA and turnip aphids in a Bonito canola crop near Neridup. The aphids were found within 50m of the fence line in the canola crop. The canola plants were at the stem elongation stage.
Growers and consultants are reminded that GPA are resistant to many insecticides, so consider applying control measures to canola only if it is unable to out-grow damage. For more information on GPA resistance refer to the PestFax 2017 Issue 4 article Green peach aphids in canola: Are we running out of options?
If canola crops are moisture stressed they will be more vulnerable to aphid damage.
Growers and consultants also need to consider beneficial insects and their role in keeping aphid populations down. For more information on beneficial insects refer to DAFWA’s Know what beneficials look like in your crop.
For more information on aphids refer to DAFWA’s recently published Protecting WA Crops Issue 3 newsletter Aphids – WA’s insect problem children.
For more information on canola aphids refer to DAFWA's Aphid management in canola crops.
For a list of insecticides registered for use on insect pests in canola see DAFWA's Autumn Winter insecticide guide 2017.