Return to the Organic Rose Growing Forum | Post a Follow-Up

 o
White spots and holes in leaves.

Posted by beffy 5 (My Page) on
Tue, May 11, 10 at 20:48

I am a beginning gardener in Indiana and am trying to grow everything organically. I have four rosebushes that are loaded with blooms, but the leaves don't look healthy. Lots of them have grayish-white splotches and holes in them. Many of the holes are a bit heart-shaped, or they have two humps. I have not seen any bugs on the plants at all, but I am assuming it must be either bugs or disease that is injuring the leaves. I had this same problem on another rosebush a couple years ago and never figured out what the problem was. Can anyone tell me what might be causing this damage, and also how I might be able to get rid of it without using chemicals?


Follow-Up Postings:

 o
RE: White spots and holes in leaves.

It sounds like your rose bushes have fungal disease..the best way to combat this is to spray some sulfuric fungicide on it. If you want a least toxic spray, try baking soda...mix 1 tablespoon of baking soda and either 2 tablespoons horticultural oil or a few drops of dishwashing liquid detergent with 1 gallon of water. Mix as thoroughly and spray on both sides of the leaves once a week. The liquid detergent helps the baking soda stick to the leaves while baking soda changes helps create a hostile environment for the fungus to grow.


 o
RE: White spots and holes in leaves.

Fungal diseases do not cause holes. You probably have rose slugs, tiny green worms eating your leaves from the underside. They are easily smushed. it's best to be on the lookout early to prevent too much damage.

If you need more info, I suggest you post on the regular rose forum, or on the antique rose one where there are many organic gardeners. This forum has gotten a bit strange and hardly gets any traffic.

Good Luck


 o
RE: White spots and holes in leaves.

Insecticidal soap can also help to control rose slugs (sawfly larvae).


 o
RE: White spots and holes in leaves.

Thanks, all, for your suggestions. I have a question for all three of you.

aero ponics, what is horticultural oil and where do you find it?

maureeninmd, would the rose slugs also cause the whitish splotches?

diane nj, what exactly is insecticidal soap and where do I get it?


 o
RE: White spots and holes in leaves.

  • Posted by jean001 z8aPortland, OR (My Page) on
    Fri, May 14, 10 at 23:38

Horticultural oil and insecticidal soap can be purchased t any garden center.

That said, no need to spray if you have only a few damagaing critters. Squishing or flicking into soapy water both work well.

Rose slugs eat the surface green off leaves. The thin tissue that remains appear to be "windows" -- perhaps the white spots you mention.


 o
RE: White spots and holes in leaves.

maureeninmd, I think you were right. I finally found some tiny green worms on a few of the leaves. I didn't find many, but I think, by all the descriptions I've read that the culprit is rose slugs. They look really amazing under a magnifying glass! Also, when I held a white plate under the bush and shook a couple branches, there were a lot of tiny black specks on the plate. I'm wondering if they are the cocoons that they come from. It kind of looked like that under a magnifying glass.

Also, jean001, I think you're right about the white spots. The leaf is really papery thin in those areas.

The little buggers have done a lot of damage in a very short amount of time. I squished the ones I found, then put a little Ivory dish soap in a spray bottle with water and sprayed the underside of the leaves. Hopefully, that will work on the ones I didn't find.

I really appreciate all the help from you all. I've spent forever researching this, but I feel that I've learned things that will be very useful in my gardening in the future.

Thanks again!


 o
RE: White spots and holes in leaves.

The tiny black specks are most likely frass (poop) from the pesky chewing insects.


 o
RE: White spots and holes in leaves.

I bought Safer Rose and Garden spray. It does not kill the bees. I called them and asked.

I am proud of you for working to learn more about gardening and what to use..especially since you are a beginner. I have been working real hard to go organic as well. I sprayed nothing last year as I kept getting conflicting reports of what is safe and what is not. What I have learned and if you learn this this year you will be ahead of where I was when I started. So many people get a few aphids and they go get a bomb spray that kills everything and treats every kind of disease for months. It's dangerous stuff. I have attended many a garden lecture and to a person they all said they use next to nothing in the way of chemicals. If you are careful with your choices of roses, sticking with healthier roses..disease resistant roses and are patient..the good bugs show up to eat the bad bugs. Having said that..I do have some roses I had to spray with Safer..and it's interesting to see that it seems like the roses that have been attacked are stressed roses..example..my minatures hardly get sun and they are in pots..any potted rose is more stressed. The rose that is not potted but has lots of bugs has two larger roses..towering way over it. So it makes sense to me. I have spent alot of time picking those rose slugs off.

I also am not above having to use an funcicide..what was recommended to me was Sulfur..wettable sulfur..it's a powder and I use a little bit and fill the container with water..and spray it. I have only done that once. Also, if you want to be organic you have to accept less that perfect looking leaves. What I do love..is all the cool birds, and bugs..and hubby even saw a garder snake yesterday. Bees buzzing around..and I love the sound of life in my garden rather than a perfect garden and the smell of chemicals all over my garden.

Stick with us..you will be glad you did...you will have a sense of pride, and your garden will be full of God's creatures.


 o
RE: White spots and holes in leaves.

Wow Zepheris: Great advice.
Like the above poster I also have a new garden. In my case ... 1 year old. To date I've only swuished bugs. I'm visiting my plants on a daily basis and squishing what I find. So far small amounts of aphids and something called oh I forget. Little green things found in little drops of soap suds. I swuish them too. BS we have a little. I pull off and dispose of any infected leaves. So far so good. However, if I saw some major damage would not hesitate to use either of the products that Zepherisis suggested as I have researched both.
Good luck to you.
Jeannie


 o
RE: White spots and holes in leaves.

Jeannie, where are u in the PNW?


 o
RE: White spots and holes in leaves.

What is the active ingredient in the Safer product?


 o
RE: White spots and holes in leaves.

I notices a wasp grab and eat one of the green worms....


 o
RE: White spots and holes in leaves.

After reading this and doing some research in one of my Jerry Baker garden books he says to hose them off with a strong stream of water and squish what you find with a gloved hand as the slugs can irritate skin. sprinkling your roses with wood ash after every rain can be very helpful as well. :-) glad I now know what's wrong with my poor rose bush!


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!


Return to the Organic Rose Growing Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.


Learn more about in-text links on this page here