Plants - Ask Extension
Good morning! Was hoping someone might be able to tell me what is decimating the leaves on my Dahlias, phlox, and more of my perennials. The leaves h...
Knowledgebase
Plants #876288
Asked July 08, 2024, 9:52 AM EDT
Good morning! Was hoping someone might be able to tell me what is decimating the leaves on my Dahlias, phlox, and more of my perennials. The leaves have huge holes, and chew marks with some already looking like lace. I can send pictures if need be. Thanks in advance.
Scott County Minnesota
Expert Response
We will need to see sharp photos of affected leaves to determine what's doing the damage. Thank you.
Thank you, attached are pictures of Dahlia leaves and phlox. The 4th picture is Phlox. Colleen
We can't be sure what's damaging the leaves without seeing the pests. However, based upon what we can see--the amount, location, and pattern of damage, we think slugs may be responsible.
Compare photos of slug damage here and see what you think:
https://images.app.goo.gl/awH4uvWBnmZpCFRF7
Due to recent heavy rain and wet conditions, slug populations have soared in many parts of Minnesota. According to some reports, slugs have damaged agricultural crops, an unusual occurrence here.
https://www.mprnews.org/story/2024/06/30/farmers-assess-crop-damage-from-heavy-rain-and-flood-water
Slugs damage occurs at night, so they often go unnoticed. To determine whether slugs are present, saturate a board and place it on the ground near the affected plants. Turn the board over in the morning. If slugs are present in your garden, some will probably be hiding there.
Go here to learn more about slugs and how to control them:
https://extension.umn.edu/yard-and-garden-insects/slugs
Compare photos of slug damage here and see what you think:
https://images.app.goo.gl/awH4uvWBnmZpCFRF7
Due to recent heavy rain and wet conditions, slug populations have soared in many parts of Minnesota. According to some reports, slugs have damaged agricultural crops, an unusual occurrence here.
https://www.mprnews.org/story/2024/06/30/farmers-assess-crop-damage-from-heavy-rain-and-flood-water
Slugs damage occurs at night, so they often go unnoticed. To determine whether slugs are present, saturate a board and place it on the ground near the affected plants. Turn the board over in the morning. If slugs are present in your garden, some will probably be hiding there.
Go here to learn more about slugs and how to control them:
https://extension.umn.edu/yard-and-garden-insects/slugs
Slugs was my best guest. Thank you for your answers, links to read and time! Colleen
Did you find any slugs? If not consider earwigs. The damage they do is similar and they are nocturnal too, so they are equally difficult to detect.
Compare here:
https://images.app.goo.gl/k256yxVwfMDWvGzS8
More information follows. (However, I think the plant identified as a zinnia might be a dahlia.)
https://extension.umn.edu/nuisance-insects/earwigs
Compare here:
https://images.app.goo.gl/k256yxVwfMDWvGzS8
More information follows. (However, I think the plant identified as a zinnia might be a dahlia.)
https://extension.umn.edu/nuisance-insects/earwigs
I haven't physically seen the slugs but our hostas are eaten up so we have that problem a lot with our clay soil out here in Credit River. I bet, from the pictures you sent, that I have Earwigs too.
I pulled Cheyenne Spirit Coneflower yesterday that clearly had Asters Yellow disease. The other 2 next to the one I pulled might be infected. I could send pictures if you are able to look at them. Let me know. The one deseased is right across from a few Coralie Dahlias that don't look the best.
What a year! I have heard from so many people that they have unbelievable flowers and bugs galore! Ha!
Coneflowers seem to be very susceptible to aster yellows. However, mite damage is similar and it can be difficult to distinguish between the two. Although coneflowers with yellows are done for, it's possible to control the mites and save affected plants.
https://www.torontomastergardeners.ca/askagardener/aster-yellows-or-erythroid-mites/
Slugs are tough on hostas, but climbing cutworm damage is similar.
https://yardandgarden.extension.iastate.edu/encyclopedia/cutworm-variegated
http://sproutsandstuff.blogspot.com/2014/06/holes-in-hosta-leaves-it-might-not-be.html
https://www.torontomastergardeners.ca/askagardener/aster-yellows-or-erythroid-mites/
Slugs are tough on hostas, but climbing cutworm damage is similar.
https://yardandgarden.extension.iastate.edu/encyclopedia/cutworm-variegated
http://sproutsandstuff.blogspot.com/2014/06/holes-in-hosta-leaves-it-might-not-be.html
Thank you for all this great information!
Wondering if I could send a few pictures again, this time of coneflowers? If not, no worries.
Have a great weekend! Colleen
Send photos if you wish.
