what could these be? Plum tree pests

tlouise(6)June 3, 2009

I have a newly planted Stanley plum tree, which I am growing organically. Every day I inspect the leaves. Regularly I am finding on the underneath of perhaps 4 or 5 leaves at a time, a mass of greenish blue little things, which I have been squishing and removing. At first I assumed they were eggs of some sort. On further inspection, I see that they wiggle and have legs. Hmm. There are a whole bunch of them under the leaves that have them. Any guesses on this?

I am also seeing ants crawling around> Are these beneficials? OR should I remove them?

Some leaves have a sticky substance on them and some of these have with tiny little white specks on them (top of leaf). I am removing these, but wonder what they could be.

Today I saw a small little yellow spider spinning a web. Thought I should leave him in, but anyone disagree? I thought he might catch and eat some of the pests..

I welcome any feedback. Thank you.

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Scott F Smith(6B/7A MD)

Those are aphids. I am also getting those guys now on my European plums. They are not beneficial, they are bad. The ants are also not beneficial, they are helping to move the aphids around to new spots. Ladybugs shoudl eventually come along to start munching, but I find I get a huge bloom of these green aphids this time every year and I need to spray them before they take over. I use summer oil. You can also coat tangletrap (suuper sticky stuff) around the trunk which will keep the ants off and will remove the aphids mobility and thus their spread.

Scott

    Bookmark   June 3, 2009 at 11:09AM
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tlouise(6)

Thank you Scott for the response, which I found very helpful. I have ordered some tangletrap..

    Bookmark   June 4, 2009 at 4:51PM
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fruitnut Z7 4500ft SW TX

For me the aphids don't need ants to move about. They have winged forms that fly. So while the tanglegunk will limit the ants, it may not do much for your problem. It is also a real mess.

There are plenty of organic controls for aphids. Harmony Farm Supply suggests and supplies parasites, predators, garlic, Neam oil, Pyrethrium, hot pepper, insecticidal soap, oil, and the one I'm using; spinosad (Monterey garden insect spray).

The Fruitnut

    Bookmark   June 4, 2009 at 6:20PM
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mudflapper

Ditto what Scottsmith said. Thank God! for the first time, I am seeing an army of Ladybug larva hatching on many trees, shrubs and vines that always get hit hard by the vermin.

    Bookmark   June 5, 2009 at 2:32AM
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miketrees(WA Australia)

Ants will actually carry and store aphids (or aphid eggs) underground, to be brought out in spring.

    Bookmark   June 5, 2009 at 7:59AM
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rhizo_1 (North AL) zone 7

SOME ants will behave that way. Not most. The relationship between ants and aphids is highly exaggerated, at least in North America.

tlouise, all you need to do with your young plum is to squish the aphids with your fingers, or spray them off with a strong stream of plain water....or both. Since you've been good about inspecting the leaves on a daily basis, this will be a simple task for you. Absolutely NO need to apply any kind of products, at all. When your tree gets larger (much larger), then you can turn to some of the very successful organic-based products to help you control aphid populations.

The sticky stuff, by the way, is called 'honey dew'. It's excreted by the aphids (and other insects that suck plant juices) as a waste by-product. It's loaded with sugars that the ants find tasty. Therefore, ants will hover around the aphids, protect them from predators, stroke them, and obtain plentiful honey dew in return. Symbiosis in action. (Some ants will take them, or their eggs, into nests to overwinter.)

    Bookmark   June 5, 2009 at 10:23AM
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Scott F Smith(6B/7A MD)

Fruitnut, I don't think spinosad is reliable on aphids. Rhizo, I have also used the water method but these green plum aphids tend to cover the whole leaf and its too hard to spray them all off with water.

The ant/aphid relationship varies a lot from type to type. The black aphids on my cherries are closely tied to ants, the ants are the ones moving them around. I also see ants moving these green aphids around but am not as sure how important they are to the spread since I see more green aphids with wings. So I would not rely on tanglefoot as the only control, especially at this point when your tree is covered with them. It is something to try next year a few weeks in time before you saw all the aphids this year.

I didn't mention my biggest control above: I just prune off all the tips where they are. They show up about now and this is summer pruning time so it fits in perfectly. The few aphids left are often enough for the ladybugs to handle. I pruned a few days ago and there are almost no aphids left at this point.

Scott

    Bookmark   June 5, 2009 at 10:47AM
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olpea(zone 6 KS)

Rhizo wrote: "The relationship between ants and aphids is highly exaggerated, at least in North America."

Not sure about that Rhizo. The relationship in KS seems to be pretty strong. Before I started using chemicals, I'd seen some pretty bad aphid problems on trees where ants were parading up and down the trunk. Once the ants were stopped (I used to use tanglefoot) the aphid problems disappeared fairly quickly.

    Bookmark   June 5, 2009 at 10:56AM
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glenn_russell(6b RI)

Same for me here Olpea-
I only see ants on my trees when aphids are there... (In fact, that's usually my first clue that they are there). I see the majority of the ants at the tips of the high leaves (where the aphids are), and any other ants are on there way to or from there. I have no doubts that my ants are farming my aphids. In the past, and so far this year, insecticidal soap is enough to rid the aphids, which then removes the ants. I may try some tanglefoot as an experiment as well. Thanks,
-Glenn

    Bookmark   June 5, 2009 at 11:10AM
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rhizo_1 (North AL) zone 7

I trust your observations; I'll have to keep a closer watch on aphids around here. Perhaps they are better behaved in the South, lol!

I still think that water and hand removal is all that our original poster needs to do for her young tree, at the present time. It's not what I would recommend for larger trees or a number of plants. Insecticidal soap would be my first choice, with Neem a close second.

    Bookmark   June 5, 2009 at 2:37PM
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carolync1(z8/9 CA inland)

I'm with Scott. Especially if your tree is up to size, nip the growing tips where the aphids are.

Check for ladybug eggs/larvae, lacewings, small spiders, etc. before throwing the leaves away. You can place them back in the tree.

    Bookmark   June 6, 2009 at 10:41AM
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alan haigh

Ants are prevalent here with aphids also but controlling ants won't stop aphids from appearing on Euro plums and cherries but it still might help control them. I think the ants can drive away lady bugs and other aphid predators. Sometimes I use ant stakes to get things under control.

Here, if I ignore the aphids and ants aren't running interference the lady bugs usually get things in balance in a couple weeks. Now if only I could figure an easy way to deal with leaf-hoppers.

    Bookmark   June 6, 2009 at 11:14AM
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renee_borg_lhsc_on_ca

I think I have these aphids too, on my 4-year old plum tree. I've got fuzzy aphidlike things on the underside of the leaf and the top side is shiny/sticky. Anyone have any 'home remedies' I can make up myself? My garden hose doesn't reach where the tree is - any other suggestions for getting rid of these? My tree is about 8 or 9 feet high now and I don't know how I will treat the upper branches? Also, I had so many tiny plums form this spring, then one day last week I noticed every single one of them was gone! Was this birds? Thanks for any advice - I've never had a fruit tree before and just put this one in last year.

    Bookmark   June 20, 2011 at 3:42PM
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renee_borg_lhsc_on_ca

I think I have these aphids too, on my 4-year old plum tree. I've got fuzzy aphidlike things on the underside of the leaf and the top side is shiny/sticky. Anyone have any 'home remedies' I can make up myself? My garden hose doesn't reach where the tree is - any other suggestions for getting rid of these? My tree is about 8 or 9 feet high now and I don't know how I will treat the upper branches? Also, I had so many tiny plums form this spring, then one day last week I noticed every single one of them was gone! Was this birds? Thanks for any advice - I've never had a fruit tree before and just put this one in last year.

    Bookmark   June 20, 2011 at 4:37PM
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