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need2seegreen

lilac: is this leafcutter, plus ... scale?

Hello!

My lilacs have gotten attacked. If you get a chance, please take a look and tell me the culprits.

I know I should take better care of them, but I only get to see them on weekends. I know they need some help!

I think it is some kind of leafcutter (but I didn't see any ants, if that helps), plus some kind of disease -- it looks a little bit like scale. Smudgy blackish goo? There are new leaf buds forming though. I hope they will be okay.

https://lh6.googleusercontent.com/-WizFJOhWhQg/UiVpuR6m_BI/AAAAAAAAAcM/ecQskEPK5mA/w536-h402-no/CIMG6089.JPG

https://lh3.googleusercontent.com/bOfzmR4dAk86uIa8rx8Mp-ez4HihabS7OzeGI6ReDMo=w536-h402-no

All suggestions appreciated!

Comments (8)

  • florauk
    10 years ago

    We can't see you pictures. Follow the instructions at the top of the post where it says 'Choose File' or upload your pix to a photo hosting site and copy and paste the html code into your message.

  • jean001a
    10 years ago

    Here's one of the pictures

    Here is a link that might be useful:

  • jean001a
    10 years ago

    And here is the 2nd

    Diagnosis of leaf chewings -- Not leafcutter bees. Instead, heavy infestation of root weevils.

    As for what to do with spotted leaves, no need to do anything this late in the season other than collect & discard all the leaves as they drop -- it's normal at this time of year,.

    Here is a link that might be useful: 2nd image

  • ken_adrian Adrian MI cold Z5
    10 years ago

    doesnt look like my kind of lilac ... are we sure on the ID ...

    wheres the matte dark green leaves??? .. the large buds.... and the bark color??

    happened to be pruning mine yesterday ... lol ...

    ken

    ps: and wheres the mildew.. LOL ....

  • jean001a
    10 years ago

    Whatever the plant, a massive case of root weevils is certain.

  • Need2SeeGreen 10 (SoCal)
    Original Author
    10 years ago

    Jean001a: thank you soooo much for your help, both with the photos and the diagnosis!!! (It took me 20 minutes just to get them into my Gplus in the first place. I'm not sure what went wrong and I'm sorry about the hassle!)

    I've never even heard of a root weevil, now I will go do a search on that.

    These are Descanso-type lilacs, bred to do well in mild winter climate. At least if you don't neglect them...

    Thanks again!!!

  • Need2SeeGreen 10 (SoCal)
    Original Author
    10 years ago

    Jean001a: thank you soooo much for your help, both with the photos and the diagnosis!!! (It took me 20 minutes just to get them into my Gplus in the first place. I'm not sure what went wrong and I'm sorry about the hassle!)

    I've never even heard of a root weevil, now I will go do a search on that.

    These are Descanso-type lilacs, bred to do well in mild winter climate. At least if you don't neglect them...

    Thanks again!!!

  • Need2SeeGreen 10 (SoCal)
    Original Author
    10 years ago

    I searched in this forum and the Pest/disease one on weevils and did not find too much.

    I googled and found this excerpt (below) -- do people think it sounds about right? I'm not even sure if/when I can find any of these items, but first, I would like to know what people here think.

    It is theoretically possible that this is the first year of weevils. I don't have photos from last year though, I don't think, so I can't be sure.

    http://www.ext.colostate.edu/pubs/insect/05551.html

    "Evidence of root weevil feeding is common but serious damage is rare. If necessary controls can be applied to either the adult stage or the larvae.

    Adult feeding, as evidenced by leaf notching, can be controlled with sprays of certain pyrethroid insecticides such as bifenthrin, cyfluthrin, and lambda-cyhalothrin. These should be applied to the foliage and it can also be useful to treat areas at the base of plants, where they rest during the day. Control may be improved if applications are made late in the day or in evening, as the weevils become active and move onto the plants after dusk.

    Larvae develop in the soil and require different treatment. The systemic insecticide imidacloprid can provide some control and is used as a drench to the soil so that it moves to the root zone. A biological control alternative are insect parasitic nematodes of the genus Heterorhabditis. (See fact sheet 5.573, Insect Parasitic Nematodes.) Treatments should be made in late spring and early summer when adult feeding on leaves is observed and egg hatch usually begins. Both imidacloprid and Heterorhabditis nematodes require that the soil be kept moist following application and the site should be irrigated immediately after application."

    Thanks in advance for all suggestions, and sorry about the double-post.