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black blobs on plum branches

Posted by mikeinsantarosa 8 (My Page) on
Wed, Feb 1, 12 at 11:45

As soon as my 4yr old Santa Rosa Plum sprouts leaves and blossoms these soft black blobs show up on some of the branches and on these same branches lots of ants show up. What's wrong with my plum tree?


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RE: black blobs on plum branches

  • Posted by fruitnut Z7_4500ft elev SW TX (My Page) on
    Wed, Feb 1, 12 at 12:06

mike:

Do these blobs move around? Do you know what aphids look like? Aphids typically show up at the time you are having trouble. They can be easily be controlled with insecticides or even a strong spray of water helps some. Some say controlling the ants helps but the aphids are easier to kill.


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RE: black blobs on plum branches

I'll check to see if they move around. thanks


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blobs could be scale

Aphids mostly stand in one spot and suck juices. But they have legs and can move slowly. Scale is more like a blob. They only move when young and then so slowly you can't notice.


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RE: black blobs on plum branches

If it's a blob that looks like bead of dried sap, but the shell breaks when poked with a toothpick, then it's probably an older scale bug.

The best tool to use on them is something like all seasons horticultural oil (the hose kind) and just soak the tree, reapply each week (as they are tough to kill) and possibly go over the surface, scraping the bugs off, if the tree is small enough.


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RE: black blobs on plum branches

Any chance of pictures? That would clarify the issue at hand.


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RE: black blobs on plum branches

*thought I just posted (sorry if redundant)*
I cheched for movement and they must be from last year because they were hollow and the side attached to the bark was open. Look like the butt end of a black widow.
I did take some pics. How do I post them here?

Thanks
Mike


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RE: black blobs on plum branches

  • Posted by fruitnut Z7_4500ft elev SW TX (My Page) on
    Thu, Feb 2, 12 at 12:00

Mike:

Those are last years scale. A picture would still help identify what type of scale. Some are much more damaging than others. A spray of dormant oil is a good starting point.


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RE: black blobs on plum branches

Google Black Knot. Maybe it's that fungus.


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RE: black blobs on plum branches

Here's a picture of a blob
Photobucket


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RE: black blobs on plum branches - pic2

here's a close-up of the bark:
Photobucket


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RE: black blobs on plum branches

The blobs are scale. Spray dormant oil asap unless you are already budding and leafing out. If later you may need a summer oil.


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RE: black blobs on plum branches

So is the blob the shell of a critter or is that the sap leaking from the branch?
The blobs I knocked off and inspected were thin shelled & hollow.
The 2nd pic has small oval shaped light colored objects all over it. Are those critters?
Scale is some kind of live infestation, right?


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RE: black blobs on plum branches

  • Posted by fruitnut Z7_4500ft elev SW TX (My Page) on
    Fri, Feb 3, 12 at 11:24

The blob is the hollow shell of a now dead scale from last year. The smaller oval disk may well be the young that will grow into the adult scale this year. Now is the time to smother the young with oil.

San Jose scale is the most damaging. Below, I hope, is a picture of one that looks something like yours and mine.

Here is a link that might be useful: scale


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RE: black blobs on plum branches

Hey fruit, that link looks pretty darn close to what I have. I soaked/saturated the tree with hort oil yesterday and will hit it again in a week or 2 if it isn't all bloomed out.

I've seen threads on this site where people knock them off with water spray or by hand. You ever try that?


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RE: black blobs on plum branches

  • Posted by fruitnut Z7_4500ft elev SW TX (My Page) on
    Fri, Feb 3, 12 at 14:12

Mike:

I mush all I find by hand. The first sign is usually honeydew on the leaves near and below the scale. Not sure I've ever eliminated them but mine are easy to kill with malathion in summer and oil in winter. Either I don't kill all or they come back. And this is in the greenhouse. Not sure how they get in.

Mine are European Fruit Lecanium scale I think.

Here is a link that might be useful: European Fruit Lecanium


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RE: black blobs on plum branches

Can anyone identify these black dots on our santa rosa plum tree? I am not sure how old the tree is or how long the tree has had this trouble, but they seem to be everywhere on the lower branches and it's really grossing me out! Please tell me it is a curable problem and that we aren't going to lose this beautiful tree! :)


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