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gilley111

What's with the leaves?

Barbara Meli
10 years ago

I purchased two rhododendron purple gem at a good sale price. When I looked closer I noticed speckled leaves. What is the problem and what do I do for it? Thanks

Comments (23)

  • ken_adrian Adrian MI cold Z5
    10 years ago

    spider mites.. or something on the back.. sucking the life out of it ...

    it wasnt much of a bargain.. if you just bought them .....

    but they should be able to be saved .... its just a question of spending some more money on them ... balance the cost/benefit ratio ... and decide to invest further.. or cut your losses ....

    ken

  • morz8 - Washington Coast
    10 years ago

    Check the leaf undersides for little varnish or tar like spots, debris....could be lace bug.

    Here is a link that might be useful: UC Davis lace bug

  • Barbara Meli
    Original Author
    10 years ago

    I figured it was spider mites. What can be done now, if anything or wait for Spring ?

  • Barbara Meli
    Original Author
    10 years ago

    I figured it was spider mites. What can be done now, if anything or wait for Spring ?

  • calliope
    10 years ago

    Don't just assume it's spider mites. You need to inspect the leaves very well, just like morz8 says and rule them out as well as ruling mites out. Although my first hunch is lace bugs. If it is, the eggs overwinter on the plant! It is one of the few gross infestations I have ever had and my azalea hedges are enormous and I got them under control very quickly. I am thinking I used insecticidal soap, and made sure that the undersides of the leaves got drenched. I had to make two applications. I also did some pruning so I could get into the core of the plants well. You should have no problem with the open canopy of your specimens. BTW NO REPUTABLE nursery sells infected stock. Nursery stock is regulated by a state's department of agriculture and is supposed to be inspected, and the growers or sellers of nursery stock are supposed to know the regulations and that includes NOT marking down and selling diseased stock. argh!

  • morz8 - Washington Coast
    10 years ago

    Don't assume spider mites without an identification, lace bug on rhododendron would be more typical given your photos.

  • Barbara Meli
    Original Author
    10 years ago

    Thanks all......I presumed spider mites never thought of lace bug. Is there anything I can do in the Fall or do I need to wait until Spring?

  • rhizo_1 (North AL) zone 7
    10 years ago

    Horticultural oil applied to the underside of the leaves will control the lacebug (no doubt in my mind that that's the problem) . Apply this fall and in the spring. Don't bother if you can't get the spray to the underside.

  • rhizo_1 (North AL) zone 7
    10 years ago

    Horticultural oil applied to the underside of the leaves will control the lacebug (no doubt in my mind that that's the problem) . Apply this fall and in the spring. Don't bother if you can't get the spray to the underside.

  • Kimmsr
    10 years ago

    According to some sources the Azalea Lace Bug is not a large enough problem to warrant control, and often predators (Assassin Bugs, Lacewing larva, Lady Beetles, pirate bugs, and spiders) may well do a good job of control. Before Horticultural oils are considered for use try Insecticidal Soaps, Neem Oil products, or maybe a superior horticultural oil. Keep in mind that even these may affect the beneficials.

    Here is a link that might be useful: About Azalea Lace Wing

  • Barbara Meli
    Original Author
    10 years ago

    Ok........I'll do nothing and hopefully watch Mother Nature work her wonders.

  • calliope
    10 years ago

    Whether azalea lace bugs are a scourge or not will very much depend in which part of the country you live. I noticed the link you sent was from California. I notice the poster is from Long Island. Here in the east, they are much more of an issue than in the west. You do NOT want to bring this insect into your garden to establish itself, especially if you have other broadleaf evergreens in that family.

    Let's put it this way.......by the time you notice the stippling, they have established themselves well. I grow almost entirely without chemicals but there have been three times in twenty seven years I've had to spray and this lace bug is one of them. The time to control a potential infestation is when it's easy to do and small, relatively open plants would be easy and likely effective. Your advice is counter intuitive kimmsr, you say before you try hort oils to use a superior hort oil? To the OP, at this time of year, on such a small area you are not likely to impact or harm beneficials with a treatment, and if you don't hit it now, you will have a new generation to deal with next spring. That's what IPM is about.

  • ken_adrian Adrian MI cold Z5
    10 years ago

    JUST THROW THEM OUT ... even if you cant get your money back ...

    to personally introduce a plague to your garden.. and then declare you will see what happens...

    doe NOT sound like a bargain that is worth it ...

    your logic is akin to going to a restaurant... and spending $10 on a cheap bargain dinner.. and BEING TOLD its spoiled.. and saying.. what the heck.. i am going to eat it anyway ... there is no doubt.. you would walk away.. and waste the $10 ...

    why not waste this bargain... and avoid future issues ... it was no bargain ... live and learn ...

    ken

  • rhizo_1 (North AL) zone 7
    10 years ago

    Lacewings aren't difficult to bring under control, but they shouldn't be ignored. If you smother the overwintering eggs throughout the winter and early spring with a horticultural oil, you will be rewarded with a healthy flush of new growth.

    Occasional treatments may be required from time to time.

  • calliope
    10 years ago

    Exactly. I'm a firm proponent of ultra-refined oils. Their mode of action will kill ANY pest if applied properly because they all gotta breathe. It also kills in ALL stages from egg to adult. It might not be considered organic, simply because it's a petrochemical but it's a very gentle pesticide if you don't want to affect beneficials. It will not kill anything not already present on the plant and once dry has no further action.

  • morz8 - Washington Coast
    10 years ago

    rhizo, you misspoke ;) and no reflection on you but I'm going to point it out for those less familiar who may be confused.

    Lacewings, and I know you know this, are beneficial.

    Lace bugs are pests, just to clarify for those newer to gardening.

  • Barbara Meli
    Original Author
    10 years ago

    Ok one confused Gardner here. Most information on line suggests moving the plants to a shady spot so beneficial insects can do their thing. The people at this site ( whom I trust) suggest spraying (yep, I know the backs of the leaves) except for Ken who wants to kill 'em. I believe lace bugs are species specific and I have many, many rhodies. I do not want to risk the health of my beloved Maxis. Am I introducing a potential problem?

  • eaga
    10 years ago

    Yeah, I think you are introducing a potential problem if you learn that your plants do in fact have lace bugs. It's great that you got a bargain on the Purple Gems, but here on LI they're easily available in season from reputable nurseries at a reasonable price. If it were me I would not jeopardize the rest of my rhodie collection (love Maxis!). No disrespect to Purple Gems, they're beautiful when well grown, but they are not so unusual or hard to find that it would be worth the trouble. Only my opinion as a practical gardener.

  • Barbara Meli
    Original Author
    10 years ago

    The screams you hear tomorrow will be my two plants being ripped from the earth

  • rhizo_1 (North AL) zone 7
    10 years ago

    Thanks so much, mor! Lace bugs are the culprit.

  • calliope
    10 years ago

    OMG whaisname...........you are all over the board on what you're going to do with them depending on who answers last. LOL ;-)

    If you have other rhodies or azalea, yes you can most definitely introduce an infestation to your property but not until next spring and not likely if you spray them like we recommended NOW with hort oil and again next spring. I grow almost entirely organically, but I can tell you for a fact that even though my property is pretty balaced with beneficials, lacebugs can and DO get totally out of hand if their numbers are allowed to grow large before you notice them. If I can eradicate them from these azaleas with two rounds of a pretty soft spray........you can certainly do it with two small shrubs. They are not hard to kill. It's your call.

  • Barbara Meli
    Original Author
    10 years ago

    Yeah Calliope I am all over the board. I want to do right by the new guys and also the old fellows. Tonight we are supposed to get our first frost so it will buy some time. Today I am planning on spraying. Tomorrow? Who knows.

  • rhizo_1 (North AL) zone 7
    10 years ago

    Well, good! I just about gave up when you said you were going to yank your new plants. Lacebugs are pretty darned easy to manage with very fundamental IPM practices.

    There are numerous options of horticultural oils for you to choose from. Whichever brand you use, be sure that you read, understand, and follow the directions.

    One more thing....and one that I think we all would agree with : inspect all plants carefully at the garden center BEFORE purchasing. Sometimes, great sales aren't such a bargain, after all. My personal policy is to avoid bringing home problems ; others don't mind the challenge.

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