Rose Disease and Insect Pests

Aphids and black spot and mildew oh my!
Aphids and black spot and mildew oh my!

I’m including in this post a video I made a while back about insects and disease. I’d appreciate it if you would take some time and watch it. Thanks.

The thing to keep in mind is that it is not a terrible tragedy to have bugs or disease on your roses. Don’t take it personally if your roses have a mildew or black spot problem. Yes, even aphids have a place in this world. Of course if you are consumed by guilt because your favorite rose is covered with bugs, curling up it’s leaves, and screaming out for help, it may just be time to get with the program and do something.

Aphids’ crawling all over the new leaves is pretty easy to identify and Powdery Mildew looks like someone went nuts and shook powdered sugar all over the new leaves. But environmental, pesticide, human and pet damage is harder to figure out. I will leave out of this post any “Round up” damage, any pet or human damage as the cure for these types of problems is at the source. Don’t spray “Round-up” on or around your roses, don’t let your dog do his business on your roses and for heavens sake don’t let your neighbor drive his car through your rose garden. Yes all these things have happened here at Rose Villa!

In the case of the big three of Pacific Northwest disease problems, (black spot, rust, and powdery mildew) keeping the disease from getting started is the first line of defense. And that means not letting the gazillion fungus spores floating around in the air settle on your roses, germinate and grow. Keeping the old leaves raked up and thrown away gets rid of a major source of infection. Good air movement through your rose garden will do wonders for keeping the fungus spores that float into your garden moving on through. When they do land, trying to keep the leaves dry by watering only in the morning will keep the spores from germinating, and when they do germinate and grow into black spots or rust, or mildew, removing the infected leaves will keep the disease from spreading. If you don’t mind spraying, a quick spray with one of the copper or sulfur fungicides will get rid of the active disease. Just remember that after the leaf is disfigured by disease it will never look any better.

Japanese beetles, aphids, cane borers, caterpillars, leafhoppers, mites, scale, and thrips. The control measures for most of these insects are the same; if you can see the insect you can try hand picking it off the rose. Yes it can be messy particularly with aphids but there are no after affects or side affects with hand picking, except for the ick factor of course. If you just can’t bring yourself to hand pick the bug, try spraying with one of the insecticidal soaps in the garden stores.

Finally, remember; roses can survive quite well with a remarkable amount of disease and insect damage. And if it just gets too bad, that gives you an opportunity to remove the weak plant and find a new plant that is more resistant to insects and disease. There are literally tens of thousands of roses of all different colors and growth habits out there waiting to have a chance to live in your rose garden.


3 responses to this post.

  1. Posted by Don on March 2, 2010 at 8:05 pm

    It’s alive I tell you, but
    Did we catch it doing wrong
    We smile foolishly, as if we didn’t know
    We preach coexistence, but
    Now its dead and gone
    Good you say, now the world is safe, but
    I think in this empty world there might be room
    for us and them too.


  2. You bring up a good (and poetic) point Don. I think that’s why Hank talks about just dealing with infestations, rather than exterminate every bug in the garden.

    Thanks for sharing the poem!


  3. So often people come to me asking for irradiation, extermination, CONTROL! It is very hard to get them to lower their expectations all the way down to just living in harmony with the other life that exists on this planet. Very often the best I can hope for is to get people to at least consider using the least harmful method of management of insects and disease.

    Also it must be remembered that human kind in its drive to survive through the ages has altered purposely and by accident much of nature. The rose is a good example of a plant that has changed and been changed dramatically through its association with humans. I doubt many people today would recognize a rose from 20,000 years ago; it would look like just another sticker bush.

    The question of course, as Don points out so well, is coexistence. As I sit here at my desk and think I realize that I have no answer. Perhaps we all just do the best we can to live and let live.


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