What I thought was BS turns out 2 be sawflies, don't I feel silly
Ok, so I am new to growing roses, this is probably evident from the title of my post, but I have acquired over 15 rose bushes over the past couple of months, most of them are planted in a mixed boarder around my front porch, but a few are in pots on said porch. About half of them have been afflicted with these grayish spots for most of the time that I have had them, seeing that they were dark in color and widespread I naturally assumed that this is the infamous blackspot I have read so much about on this forum.
WELL, apparently I have been horribly mistaken, I just returned home from my favorite local greenhouse, and while I was there shopping for roses (that I certainly don't need and barely have room for--I have this problem--I know most of you will understand what I mean)
As I was asking the bush and shrub expert about a struggling Ebb Tide I have (the leaves are turning bright yellow and the buds seem to be dying before they even have time to flower- if you have helpful info I'll be glad to hear any) I look over at a random rose that is nearby and it also has my familiar gray spotting & I just happen to think to ask "is this blackspot?" and she says, "No, that it is damage from a sawfly." Well my mouth just fell right open. Don't I just feel super silly that I have been reading up on blackspot for weeks, trying to find out how to prevent it & treat it organically, yadda yadda, and this whole time I have been researching the wrong thing.
So I ask her what I can do to stop this and she lists several types of sprays, insecticides, etc, when I ask her if there are any organic treatment options she pretty much laughed and said "growing roses organically- forget about it!" I appreciate her advice so much, but I know there have to be other options out there, does anyone here have anything that has worked for them in the past to treat sawfly infestations without hurting beneficial insects? Any advice will be much appreciated!
Jessica
From Better Homes & Gardens:
Sawfly Control
The best time to control sawflies is early in their larval stage. The natural insecticide spinosad will control sawfly larvae. Conventional insecticides such as malathion are also effective. Bt (Bacillus thuringiensis), which is an effective natural control for true caterpillars, is ineffective on sawfly larvae.
Other links:
http://forums.gardenweb.com/forums/load/rosesorg/msg0612322529186.html?5
http://homeguides.sfgate.com/spray-roses-spinosad-sawfly-65711.html
http://beesandchicks.wordpress.com/2011/05/24/tuesdays-tips-%E2%80%94-spinosad-for-garden-pests/
Wipe the little green worms off the lower surfaces of infested leaves with your thumb, or spray Safer Soap with 100% coverage of those same surfaces. Actually I don't have to do anything, because wasps pick off most of the worms. The spots are areas where the lower surface of the leaf has been nibbled off, leaving the translucent upper cuticle, which looks whitish.
Copper soap or plain micronized sulfur provide some protection against blackspot, if used faithfully.
Thanks for the suggestions guys! I will certainly be researching and trying these options. I have looked at the undersides of the leaves several times in the past, suspicious that the few spots that did actually fully develop into holes were not actually BS, but some sort of caterpillar or something of the like, but I never saw any larvae or any bugs really, besides aphids, and they really aren't doing much damage if any, so I just spray them off. I will however continue to look for them.
On the bright side, I should probably never say these words aloud, but at the moment I think my garden may be completely free of blackspot! Now that I know what to look for I am pretty certain that there is absolutely not a trace of BS on any of my roses. The Ebb Tide with the yellowing leaves is the only rose that could possibly have a "disease", (although I'm pretty sure it is something other than that). As a very new rose grower in the humid east TN valley, I feel very lucky & very surprised that I don't have to deal with blackspot (yet).
Best of luck with your saw fly (rose slug) problem...
I have used Spinosad or Safer Soap with decent results in the past...
This year I'm not spraying I'm going to take some time and study the rose slugs activities and take some pics and maybe a video...
Right now I've got minor to moderate white spotting damage on leaves. Not many holes yet...
Dinglehopp3r,
Here is a picture of a sawfly worm. I just pick them off and toss them on the ground. They donâÂÂt climb back up the canes. Never done it but I read a lot about people just hosing them off the leaves.
toolbelt
Here's what our Rose slugs look like... I took these pics toward the end of last year...
Just use the search function at the bottom of this page--insert "rose slugs" or "sawfly"--you should pull up dozens and dozens of pages covering what to do.
And remember that it is possible that wasps have already killed off your rose slugs and what you are viewing is PAST DAMAGE, not on-going current damage. Those leaves will not heal themselves. As NEW LEAVES develop, they will cover up the older damaged leaves.
Kate
YIkes, Jim, watch out for yellow jackets! Cool picture, though.
I didn't mention spinosad because IMO, soap works. However, spinosad is considered "organic" and does minimal harm to beneficial insects.
I don't have any blackspot yet either, but this has been an unusual spring. BS pressure is very high in East Tennessee, so the OP should choose roses that are recommended by growers in Appalachia and the Mid-Atlantic areas. "Disease resistant" in the catalog is meaningless.
Also the good thing is some areas Rose Slugs are only around for a shorter period of time. Depends on how many generations they have to produce offspring...
So they already may be gone for the year...
Michaelg- I agree safers soap would be the safer product to use. I used it for awhile with good results but then I started getting less than good results but not sure why?
Ok so, another epiphany, this explains why there have been so many yellow jackets hovering around my roses recently! It seems that they have already taken care of the problem for me! And to think, I used to be terrified of anything that resembled a wasp, but really they are just my helpful garden pals.....as long as they stay away from my head. (I have very bright orange/red hair & get mistaken for a flower quite often by bugs) I am so relieved! Thanks again everyone for your tips and advice!
Jessica
It's not a bad idea to be afraid of yellow jackets. Other kinds of wasps will do this service without attacking the gardener--although yellow jackets don't usually do that until October, unless you get too close to the nest. Anyway, if you have paper wasp nests in the eaves, let them be, because they will help with the rose slugs and other worms in the garden, and they won't sting unless you ask for it.
After a little research I am pretty sure what I have are paper wasps, they are a little longer and more slender than some photos of yellow jackets, and they don't really seem to be too aggressive, I tried photographing one that kept flying around and around my potted golden celebration (my rose with the most leaf damage) it was very obviously checking the undersides of leaves & it payed me no attention at all. It was kind of neat to see this in action, these bugs are obviously pretty intelligent and seem to remember finding the larvae in that area before. BUT don't get me wrong, even if this type of wasp is less aggressive than actual yellow jackets I am still terrified of these little critters. Especially after researching them and reading a few of those horror stories out there. I just hope I never happen upon these guys' nest, I don't see it anywhere on my porch or my yard, so hopefully it's in my neighbor's yard!
Michaelg, when you say yellow jackets usually don't do that until October, do you mean that they usually don't show their faces until that late in the year, or that they seem to be more aggressive around that period of time?
As I understand, the yellow jacket workers will not survive winter, so they become randomly aggressive in the fall, by way of teaching other species not to mess with yellow jackets. They are present all summer, with numbers increasing over the season. The nest is a burrow with an entrance 2-3" diameter in well drained soil, preferably on a bank or behind a retaining wall but sometimes in turf. They furiously defend the area near the nest.
Mud-daubing wasps are generally harmless, and paper wasps will sting only if antagonized.