Managing Cabbage Aphids Dusty Severtson: DPIRD Research Officer
Cabbage aphids are a common pest in canola in Spring but they’re not a pest in every
crop in every year. So it’s important to get out and have a look,
so let’s have a look. There are 3 species of aphids that we have
to worry about in canola in Australia, the cabbage aphid, the turnip aphid, they generally
cluster on the racemes We also have the green peach aphid, it’s more
of a pest early in the season and more renowned for vectoring viruses. But where crops are stressed, they can certainly
affect advanced crops. So where do we look to find cabbage aphids? Well firstly they like to be on the branches,
and you can see how they cluster and cause flower abortion, reduce seed set and that’s
generally how we get a yield loss. It’s a good idea to start on the edges first
and you work your way in to see if there’s strong edge effects in their distribution. How cabbage aphids distribute themselves in
the field is very important when you consider how to monitor for them. And we found cabbage aphids are very easily
over or under estimated because they’re quite aggregated. So what we did as part of a GRDC project,
is look at how we can improve the accuracy and in doing so we produced an APP called
Crop Scout which is part of the My Pest Guide suite of Apps. So what I’m doing with the Crop Scout App
is every 5 paces I’m inspecting a plant and if it’s infested I click Yes and if it’s not,
I press No. And the algorithms are running in the background
for me and it will actually stop when it knows I’m above or below a threshold for this particular
path. So where we want to go to in the future is
really improved monitoring to increase accuracy of sampling and monitoring and decrease unnecessary
sprays. So we encourage you to get out and have a
look at your crops, what’s going on in there- often it’s more than 1 pest, and it’s really
important to get an idea of what’s going on in there, and the populations of pests and
beneficials that you have in your crop.