insect infestation on kale plants - Ask Extension
We have a heavy infestation of indects on our kale crop. Red Russian, white Russian, and Siberian kales are all affected. We've grown these for decade...
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insect infestation on kale plants #723079
Asked September 11, 2020, 8:35 PM EDT
We have a heavy infestation of indects on our kale crop. Red Russian, white Russian, and Siberian kales are all affected. We've grown these for decades and this is a first for us.
Can you identify and possible offer an organic remedy? Cabbage aphids maybe? Photos attached.
Thanks as always,
John
Anchorage County Alaska
Expert Response
Hello,
Yes those are aphids. And that does look like a bad infestation. The trick with aphids is persistence. We generally recommend a mixture of 2 cups rubbing alcohol, 5 cups water, and 1 Tablespoon dish soap. The alcohol encourages the aphids to release, and the dish soap leaves a residue which they dislike so they are less likely to re-attach. Also, strong jets of water can be used to wash them off. In order to get them out of the garden/bed you need to change the ground cover they fall onto. A common attack plan is to lay some straw around the infected area. Spray to wash off the aphids, then remove the straw with the aphids hiding in it. This will likely have to be done several times over the year to keep the population and damage down. So keeping an eye out for them is important to keeping the damage to a minimum.
Aphids, like most pests are opportunists so when the conditions are right the population can grow quickly. The idea is to keep the population low, or the conditions unfavorable so the crops can grow.
Yes those are aphids. And that does look like a bad infestation. The trick with aphids is persistence. We generally recommend a mixture of 2 cups rubbing alcohol, 5 cups water, and 1 Tablespoon dish soap. The alcohol encourages the aphids to release, and the dish soap leaves a residue which they dislike so they are less likely to re-attach. Also, strong jets of water can be used to wash them off. In order to get them out of the garden/bed you need to change the ground cover they fall onto. A common attack plan is to lay some straw around the infected area. Spray to wash off the aphids, then remove the straw with the aphids hiding in it. This will likely have to be done several times over the year to keep the population and damage down. So keeping an eye out for them is important to keeping the damage to a minimum.
Aphids, like most pests are opportunists so when the conditions are right the population can grow quickly. The idea is to keep the population low, or the conditions unfavorable so the crops can grow.
Thanks for your prompt reply and your expertise.
Since I've been growing several brassicas here for decades without the aphid experience, the questions I have are:
Are these cabbage aphids?
And are they fairly common in South central Alaska?
Thanks for your help. It's always helpful to have a knowledge based approach.
Hello,
It's hard to tell. They may be birch or cottonwood aphids who have jumped hosts. We've had fairly high numbers in Anchorage this year and they will do that. Fireweed aphids will also shift. But aphids are a common garden pest in SC AK.
It's hard to tell. They may be birch or cottonwood aphids who have jumped hosts. We've had fairly high numbers in Anchorage this year and they will do that. Fireweed aphids will also shift. But aphids are a common garden pest in SC AK.
Thank you !
