Weird non-slug holes in leaves (Warning - photos)

18 years ago

Wow, you guys are my problem solvers this week. Anyone had this happen?

I'm getting strange holes in one of my hostas and the mini rose next to it. I know it's not slug damage because before the hole, an irregular patch of leaf turns transparent. Within the few days, the transparent part flakes away (or something) and leaves an irregular hole.

This happened to the hosta last year, and I think the rose as well. They've been in that spot for several years. The only change I've made was to swap them last spring - I moved the rose forward about a foot and the hosta back (what would possess me to plant a mini rose behind a hosta?). Last fall I posted this question to the hosta board and everyone told me the plant was getting too much sun. That's obviously not the case since these plants have been here quite happily for a number of years.

Last year there wasn't a single leaf left on this rose by winter. I'm hoping someone knows what this is and how I can treat it. Thanks in advance for any help!

Sort by:Oldest

Comments (9)

luvmydaisies
18 years ago
Have you noticed any bugs on the leaves that might be eating them??
Carola_MN
18 years ago
I also have this on some hostas and roses. I think it's sawfly larve damage. It's been an epidemic in many states on roses this season, but I had this on my hosta's last year too. I think neem oil helps with this pest. I'm not sure about other insecticides since I'm very reluctant to use them since they kill beneficials and set off a cycle of spider mites. I have one one bush that can't seem to shake it off, so I may go that route.
Related Professionals
Essex Landscape Architects & Landscape Designers · Lakewood Landscape Architects & Landscape Designers · Brookfield Landscape Contractors · Canby Landscape Contractors · Cary Landscape Contractors · Deerfield Landscape Contractors · Fort Atkinson Landscape Contractors · Lehigh Acres Landscape Contractors · Mastic Beach Landscape Contractors · Middleton Landscape Contractors · Petaluma Landscape Contractors · Soddy Daisy Landscape Contractors · Streamwood Landscape Contractors · Vashon Landscape Contractors · West Haverstraw Landscape Contractors
selkie_b
18 years ago
UGH! The bottom one looks like Japanese Beetle damage. They REALLY love rose leaves. Neem oil does indeed work on sawfly larvae, the beetles, and any loopers too.

-Marie
fitzerroneous
Original Author
18 years ago
Thanks. I've inspected these plants at all different times of day and night and haven't found any bugs, so they must be pretty well hidden. I've never used Neem oil - is it completely safe? It sounds like it's definitely not a chemical pesticide.
rose3
18 years ago
I've got some plants that look just like yours. I mix up a concoction of 1 quart of water, 1 tsp. baking soda and 1/2 tsp Neem oil. Seems to be doing the trick. I got my Neem oil off ebay. It seems safe - haven't noticed any damage to the plants or blooms.
fitzerroneous
Original Author
18 years ago
Rose, do I need to get the top and bottom of each leaf as I spray your mix? That might be really hard to do with the hosta, but I know a lot of remedies don't work if you don't totally coat the leaves.
kari_falconhts
18 years ago
The holes in the rose look like the sawfly larvae (aka 'rose slug') damage that are devastating my roses this year. Apparently they're not real finicky about what they eat (rose leaves, buds, stems) as well as my Columbines-- sometimes they eat those small transparent holes in the leaves, sometimes they edge along the leaf and devour it as they go. Look for little green caterpillar-worms under leaves or curled up inside them. I haven't had much luck with the neem oil, but I have a major infestation. Definitely spray under the leaves as they hide out there, and spray the ground around the plant, as I read that they pupate there.

a couple of web pages I found helpful (and totally icky):
http://www.ext.vt.edu/departments/entomology/factsheets/euroslug.html
http://www.ars.org/About_Roses/pests_slugs.htm
http://www.agnr.umd.edu/users/hgic/diagn/broad/roseslug.html

I haven't had any sawfly larvae on my hosta -- yet that is. Good luck!
mshiffl
18 years ago
Saw on my hostas tonight bugs similar in size and shape to box elder and lightning bugs only they are black and white. They have torn my hostas up just like the photos and also with stringy ends on leaves. I haven't yet looked up the name of these bugs maybe someone else already knows. My bushes were loaded with them. I signed up to share this. I'm not much of a gardener.
sallym
18 years ago
mshiffl,
Start a new thread. more people will see your post. You can also try the pests and diseases forum