Help identify whats happening to these plums
- Thread starter mtuckr
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Are the leaves affected in any way?
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Unfertilised. No bees?
I think you have a most valid point there. So much poison is being sprayed onto garden crops, it decimates the wild life, and nature doesn't stand a chance.
The ''eyes'' on the little abortion in the photo makes it look like a martian
Those look like holes, maybe there is some creature boring into the fruit?
Look up shot hole borer beetle.
Why is there a hole in my plum?
The Shot hole Borer is most common on plum, apple, pear and cherry trees. The holes are caused by the Shot hole Borer beetle and the life cycle is as follows: The adult beetles (black / dark brown) bore small holes into the wood in May / June time where they lay about 50 eggs.
I copied and pasted this from the internet.
The Shot hole Borer is most common on plum, apple, pear and cherry trees. The holes are caused by the Shot hole Borer beetle and the life cycle is as follows: The adult beetles (black / dark brown) bore small holes into the wood in May / June time where they lay about 50 eggs.
I copied and pasted this from the internet.
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That simplifies things then. If the leaves had been affected I would have said the problem was a leaf spot fungus. What you have are Plum Sawflies. There are many different types of sawflys but in this case only two are of importance, the Yellow Plum Sawfly and the Black Plum Sawfly. Neem Oil is the preferred organic means of controlling them but ONLY if the Neem Oil is fresh AND it is labeled as 100% Cold Pressed Neem. It the label reads Neem Extract it will not work. Cold Pressed Neem contains azadirachtin and the extract does not.
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Thanks Chuck. It does seem to be the sawfly- and to answer others it’s not an issue of pollination. We have been spraying neem oil mixed with other things but it still seems to be an issue. I confirmed it is cold pressed neem oil. Is it important to spray neem oil alone and it mixed with kelp and fish hydrolysate? Is there a best practice for the most effective times to spray? We sprayed when it first started leafing, when buds emerged and when the flower petals fell off. Thanks!
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If the Neem has been opened it has a shelf life of about 6 weeks before it starts to lose effectiveness. It does not matter if you spray Neem mixed with kelp or fish emulsion but in this case I would not mix anything with the Neem. Plum sawfly have 2 generations. The first, and most important way to control them, is to eliminate as many as possible before they have a chance to turn into the larvae that affect the fruit embryos. Plum sawflys overwinter in the soil beneath the tree, emerge as adults and then lay eggs which turn into the larvae that kills your fruit. Kill the overwintered insects and you solve your problem. You do this by a strict cleaning and LIGHT cultivation of the areas beneath the tree as soon as the tree loses its leaves in the fall. If you have to, get a shop vac, rake and vacuum everything up beneath the tree and burn it. The use of beneficial nematodes in conjunction with removing ALL debris is also extremely effective. Also, using a spinosad soil drench beneath the tree is effective. Now for the Neem Oil. Since you have a serious infestation of sawflys you should spray the tree AND drench the soil 2 times. The first time is as soon as the tree loses its leaves and becomes dormant. The second time is at BUD SWELL. If you wait for leaves or blooms or buds you are too late.
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