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Slugs or what #751454

Asked May 22, 2021, 11:32 AM EDT

Holes in Tuscan kale and tomatiilos despite a lot of Corey’s. Are they from something else? If so how to fight it?

Washington County Oregon

Expert Response

In addition to slugs and snails, there are several insects that like to munch on vegetable crops in our area. 
The most likely culprits with your kale are cabbage worm and cabbage looper.  Cabbage worms are the larvae of a pretty little white butterfly you may have seen flitting around.  Cabbage loopers are the larvae of a moth.  The links above have great pictures of these insects at egg, larval, pupa, and adult stages.  As you can see, the caterpillars are green and very hard to spot in among the leaves so you really have to look closely.  If you want to avoid spraying insecticides, the best way to manage these insects is a combination of manually searching through the plants and the soil below for the caterpillars and disposing of them, and then placing a floating row cover or insect mesh over the plants to keep the adults from laying more eggs on them.  You'll have to inspect the plants every day for a while as one caterpillar can decimate a plant overnight.  While you're inspecting, get rid of any eggs you may find as well.  If you use floating row cover or mesh, make sure to bury the edges or use boards or pieces of rebar to weigh them down with no gaps so that the adults have no way to get in.  Since you'll have to move the barrier every day to inspect your plants, the boards or rebar are an easier option to take off and replace.  If you are willing to spray insecticides, you may want to try Bacillus thuringiensis as that is the least damaging to other beneficial insects and is effective on both cabbage worms and loopers.  Below are links for dealing with both insects that include other chemical control options.  You can use anything under the "Home Use" section, but make sure to follow the label instructions exactly on any pesticide you use.  Luckily most of the deterrents are the same for either insect.
https://pnwhandbooks.org/insect/vegetable/vegetable-pests/hosts-pests/collard-kale-imported-cabbageworm
https://pnwhandbooks.org/insect/vegetable/vegetable-pests/hosts-pests/collard-kale-armyworm-cutworm-looper


If you have cabbage loopers, it's possible those are also eating your tomatillo leaves.  Another likely culprit is the flea beetle, though the holes in your tomatillo leaves look a little big for that.  The methods of dealing with any caterpillars eating your tomatillo leaves are the same as the cabbage looper information above.  If you think you have flea beetles and want to deal with them, here is a link on what you can use:

https://pnwhandbooks.org/insect/vegetable/vegetable-pests/hosts-pests/tomato-flea-beetle

I have all of these insects and mollusks in my Washington County garden and with enough time and effort they can be controlled without pesticides.  But then, I spend a lot of time out there and I do still lose some of my bok choy to fast chewing caterpillers and slugs.  Best of luck with your harvest!

Thanks so much Larina. I have my work cut out for me. Should i assume they are not slug holes, ie should i hold off on the Corey’s and beer? Roger

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On May 24, 2021, at 8:48 AM, Ask Extension <<personal data hidden>> wrote:


The Question Asker Replied May 24, 2021, 12:38 PM EDT
Hi, Roger-

It may well be both caterpillars and slugs/snails.  Slugs and snails often leave behind slime trails so that's one way to tell who is making which holes in which leaves, but they aren't always visible.  The easiest way I can tell between them is their droppings.  I don't know how much you want to know about this, but slug and snail droppings are more elongated and are often stuck on a leaf or stem near the damage and caterpillar droppings are like little pellets scattered all over, often on a leaf below the damage.  On my bok choy it's very easy to see because of the pure white stems and I definitely had both slugs and caterpillars over the last weekend.  On your kale it may be more difficult to see.  I can't make out either on your pictures, though there may be a hint of a slime trail near the top of that most heavily damaged leaf.

If you're getting rain like I am this morning any signs may have been washed off for today, but next time there's a clear morning have another look.  Living here in the Pacific Northwest, I'd be very surprised if you didn't have any slugs or snails looking for dinner.
Thanks, Larina. Very complete and helpful answers.

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On May 24, 2021, at 10:41 AM, Ask Extension <<personal data hidden>> wrote:


The Question Asker Replied May 24, 2021, 2:44 PM EDT

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