Plum Curculio

If you want to stay on a soft side. What about spraying it with Spinosad?


I use Surround on my cherries. Its pretty much gone by harvest. For several years I was not using it, but then I noticed the curc would attack the cherries if everything else had Surround on it. So, now I spray the cherries as well. I also use spinosad as the cherry fruit fly and OFM also can attack cherries. Spinosad is not effective for PC.

I am in a major Surround spray period now since everything is nearly synchronized this year: apricots, peaches, Jap. and Euro. plums, cherries, pears. Half the apples have dropped petals so I am hitting those as well now. I did three hours of Surround spraying today and didn’t quite finish, I’ll get the rest in the next day or two.


Did you mention in the past that adding MSG to Spinosad is enhancing its efficacy? I have OFM, too.

I also just ordered another bag of Surround. I arrived last week.

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Someone else mentioned that so I picked it up and started doing it. I always add some, not sure its helping or not but it only takes a few seconds to throw it in. 1/25tsp per gallon.

1/25 tsp. That’s a pinch or less :grinning:

Yes, hardly any.

On the general topic of PC, this year I have so far found a few PC bites on my Spring Satin and my Nadia, but on nothing else. I put down nematodes last year and I am wondering if they helped out as I am seeing much less damage than I usually do. (there are a couple threads here on nematodes - e.g. Nematodes for PC control) My apricots are almost too big to be bitten and I have not found a single bite on them so far.


Approximately what is the size apricots when the PC quit biting them and does this also apply to plums and pluots. Thanks, Bill

Hi Scott,

How long does the PC cycle last in your area?



PC can go through up to 7 generations, if you don’t pick up the fallen
infected fruit. Which means you’ll be constantly spraying.

Where I live in the northeast, PC has 1-2 generations.

OFM has up to 5 generations in one growing season. I’ve seen flagging shoot damage way into late Sept.


Generally by quarter sized on any fruit the PC has lost interest, and even a bit smaller than that. The PC worm needs to get into the seed before it hardens or the seed cannot be eaten and the fruit will not abort. The only exception on this timing I have seen is prune plums, they love to bite the necks at larger sizes, even if the seed may be hard by then.

I should add one minor revision to my remark above that they start biting at dime-sized. Its slightly smaller than that, more like AA battery size (the diameter of the battery). This is on stone fruits, on apples and pears its pea sized. I found a few bites on some asian pears that are big peas now.

In the mid-atlantic it has only one generation per year, two further south, and I don’t think it has 7 anywhere. It sounds like you are thinking of OFM?

In any case picking up drops is very important. I forgot I was much more diligent last year on picking up drops, and that surely helped reduce my population this year. So, it was not just the nematodes that helped me.

For me my last spray is around the end of May. PC pressure is high for about five weeks, hit it hard in that period.



We’re supposed to have only one PC generation here, but I always find larvae in nearly-mature plums, especially prune plums. The earliest to ripen can be assumed infested

I also get those, and believe they are from the neck-bites I mentioned above - they are later strikes and since the larvae can’t eat the seed they stay on the tree. The neck bites can also happen on non-prune plums but they favor prune plums for them. Its important to keep the control on the Euro plums going a bit longer than on the other fruits, otherwise you can get a lot of these late neck bites.

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what is MSG?

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You’re right Scott, I got the two confused, but picking up drops is the key
for both. I usually only spray twice

Monosodium glutamate, flavor enhancer. It is used a lot in Asian sauces and dishes esp. Chinese food.

Got it, thanks. I knew what MSG was, but not in the context of spraying it on my trees I guess.

Scott mentioned it last year. I was surprised but happy to give it a try. I went out and bought a large bag of it (before knowing how much it is needed per a gallon of water. With the bag I have, it could last until the next millennium. I’d be happy to send it to you but with sending white powder in the mail…better not :smile:


I’ve gotten lots of neck bights on Chickasaw type plums before as well as on Mariana plums which probably should be more or less lumped in with European plums even though one of the parents to this variety is the native Monson plum.