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cousinfloyd

protecting persimmon grafts from psylids

cousinfloyd
10 years ago

I've noticed lots of these little gnat-like insects on my persimmon grafts since I started trying (with very minimal success) to graft more persimmons last year, but I never thought much about them until just the last few days. I just read the following on Edible Landscaping's webpage:

"In midsummer there is a small insect that looks like a large gnat (psylid) at 1/8" long, that will suck on newly emerging leaves. Their cycle is approximately 1 month. I've never seen them set back an outdoor tree and in the fall their damage is not really noticeable. If they are alarming they can be controlled with sprays. Since they ar soft bodied a soap spray can be effective."

The "newly emerging leaves" stage is how far most of my grafts make it before they lose vigor and finally dry up and die. These psylids may not be my main problem with grafts failing, but at this point I want to do everything I can to improve, so I want to see what I can do to deal with them. Should I take floating row cover material and make a little net around each scion? Will that affect temperature any (i.e. it won't cause the graft to overheat, will it)? Do I need to find a way to suspend it above and away from the new growth or is it okay if it rests directly on the new growth? (The psylids won't cause damage through the material, will they?)

I'd mostly like to find a way to graft onto wild seedlings I already have growing all over my place (i.e. outdoors/in the field), but another thought is to keep potted grafts indoors until they're a little further along. I wouldn't be able to give them hardly any direct light if I kept them indoors, but maybe light wouldn't be all that important at first.

Comments (11)

  • Scott F Smith
    10 years ago

    If you have a small area apply insecticidal soap periodically - it will kill all the psyllids. Get them before the leaves start curling; for any you got too late, uncurl with one hand and spray with the other. You need to spray about twice a month.

    Its good to try to keep grafts free of them so they can establish well. Once grafts are going the tree can tolerate a few of them without much problem.

    Scott

  • cousinfloyd
    Original Author
    10 years ago

    Scott, thanks a lot for the advice. I don't think I understand the insecticidal soap idea. Doesn't it only kill the psyllids that are on the graft when I spray it? It seems like I'd have to spray it every 10 minutes for three weeks. How can twice a month spraying really make a difference? In the meantime (before seeing your reponse) I went ahead and put a little upside down bag of floating row cover material over each of my persimmon grafts that hasn't really elongated any new stem yet. Spraying twice a month definitely sounds easier, but do you think what I did will work just as well? Thanks again,
    Eric

  • Scott F Smith
    10 years ago

    Eric, the problem with rowcover is as the plants grow. Now that its on keep it on, but if the grafts work they will soon be bumping into the cover and you will need to take it off then.

    The psyllae take several weeks from egg lay to curled leaf, you are killing half a generation each spray. Probably every three weeks will work, just keep an eye out for any sign of curling.

    Scott

  • cousinfloyd
    Original Author
    10 years ago

    Perhaps among other things I'm confused on the life cycle. Is it the adults that do the damage? Or do they lay their eggs and do their eggs then hatch and feed/mature on the newly emerging persimmon leaves? At this point I figure I've excluded the adults, but if there are other stages already in there, then I figure they're still a threat. I do realize I'll need to take the row cover off soon, but if I can just get the new growth to put on two inches of new stem (which I think the row cover will accommodate), I think I'll be fine from there.
    Thanks again,
    Eric

  • Scott F Smith
    10 years ago

    Eric, adults lay eggs on green buds and newly formed leaves. Its the white little bugs coming from the eggs that cause the damage.

    Scott

  • cousinfloyd
    Original Author
    10 years ago

    Scott, just to clarify, it sounds like the covers I put over the scions (that already had elongated green buds or were already unfolding leaves) should have been put on earlier if they were going to do any good. So it sounds like insecticidal soap is the only thing that might help at this stage. Does that make sense?

  • copingwithclay
    10 years ago

    If I am going to go through the effort of acquiring quality graftwood, taking time to graft, and watering/caring for a fruit tree, I will also use a cheap grafted scion defensive cover that takes little time to provide. You can make a plastic sleeve by scissoring a 4" wide by 8" long section from a thin, white plastic grocery bag. Fold the 8" side over to the other side and tape a full-length seam with clear Scotch tape. Then fold over a 1/4" end flap and tape the 2" seam there to form a cul de sac in the "bag". You want to end up with a sleeve that is 2" wide by 8" long and closed on one end. Slide the loose-fitting "tent" over the grafted scion and Skotch-tape the open bottom to the side of the branch below the graft , leaving a bit of the open tent bottom untaped so air can pass through. Because there are lots of squirrels, birds and lizards at this place, the fluffy white tent does not look like a normal place to land on, climb on, or jump on to these critters. Flying insects looking for a place to get some veggies to munch on or leave eggs...will fly to a better looking site to stop. After enough weeks waiting time for the graft to heal and growth to begin, you can check it regularly until the young leaves are beginning to crowd the tent space a little. Then, it is time to toss the tent from this growing scion and either replace the 2" by 8" tent with yet a bigger tent, or let it face the cruel world w/o the defensive cover. Because these are thin and white, enough light goes through for the leaves to grow healthy, and hot Summer Sun light won't cook them while waiting for the healed graft to start flowing a full supply of sap to the scion. I have used them on many different kinds of fruit tree scions. To me, it is akin to having a child and taking good care of them...rather than letting them...let's see....maybe riding in the back of a pickup truck while going 55 MPH down the hwy...or some other dangerous, negligent activity that is not necessary.

  • bennylafleur
    10 years ago

    Eric

    just for information, I had some of the little critters on some new tender growth a few weeks ago, and the closest thing I had was Windex. It killed them immediately, and did not harm the plant.

    Benny

  • copingwithclay
    10 years ago

    bennyl: I do use Windex to spray on pomegranate fruit when I see a 'herd' of baby , orange-colored leaf-footed hoppers perched on the fruit. It kills them in seconds after only a couple squirts drench them. When I see the somewhat older, grey/brown individual l.f.h. on a pom, it takes multiple squirts and a couple minutes before they fall down and die. If I try the Windex on a full sized l.f.h., it takes many continuous squirts and several minutes to kill them. Although the liquid evaporates soon, many squirts leave enough residue that is absorbed through even the thick pom covering that in hot Summer the unrinsed fruit will die. Rinsing the sprayed plant is beneficial.

  • cousinfloyd
    Original Author
    10 years ago

    Thanks for all the suggestions.

    I'm definitely going to do something like you suggest with persimmons next year, Coping. The last few years I've mostly just grafted pears, and they've just been so easy and trouble-free (until they get older, start flowering, and get fireblight), but persimmons for me seem to need all the special treatment they can get.

  • Scott F Smith
    10 years ago

    Floyd, I missed your question above. If the buds were green already you may have been too late. Get ready with the soap or windex.

    Scott

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