What to do after curculio hits?

After all my work to get my plum tree to set some fruit, it looks like I have plum curculio!!

Fruits are falling. I’ve opened the fallen fruit and find a little worm and the insides look brown.

Is there anything I can do at this point?? I’m picking up the fallen fruit and putting it in the trash, to reduce future incidents. But, at this point, am I just waiting and seeing which fruits have it and which don’t??

I would say if there are fruit with no crescent scars to take action immediately. I would spray Surround on the remaining fruit. You could also use a pesticide, but I never have so I don’t know which one you would apply.

People recommend putting a bed sheet under the tree early in the morning and shaking the branches. The insects natural reaction is to fall and play dead. Then collect them off the sheet and dispose of them.

There are more than one pest that like to bore holes in plums. Read up on plum curculio, Oriental Fruit Moth and coddling moth from university sites like Cornell, Penn State. You may find out you have more than PC.


Will go out there and start checking fruit. I wasn’t sure if they little buggers infect the fruit way earlier or if they continue through the season.

I was kinda hoping that the damage had already been done and i was just in a “wait and see what wasn’t damaged” mode. :joy:

You can use Malathion or any insecticide labeled for PC. It’s probably too late though.
You need a sticker too! And use acidic water, add a tbsp of vinegar.

Well depends what the problem really is. Some of these do attack again.

Here some pics. I’m a bit confused about the crescent shaped scar. Maybe someone can take a look at these pics and give me some direction?

The first and second pics are the same plum that I found on the ground. Is that a crescent shaped scar?

Third pic is a plum on the tree that hasn’t fallen.

Fourth pic is a plum that was on the tree, but was about to fall. Early coloration, but has holes at the top.

I don’t believe any of those are a PC laying scar. In the last photo, it could be an exit hole. The first 2 look like fruits that were infested, but the larvae have left

I’m sorry to hear about your bad luck. THis is one thing I’ve had a lot of experience with, and I am afraid you may have lost most or all of your fruit. But we hope not. OK, the crescent shaped scar looks like a moon in early stages. Just google Plum curculio scar and look at photos and you’ll see. Your first photo above shows a classic crescent scar. The spots on the last 2 photos don’t look much like PC, but could be. Like @mamuang said, there are other things that make scars on fruit.

Just so you know, how it works is that Plum Curculio cuts a small, crescent shaped flap in a fruit and lays an egg just under the flap the skin on the fruit where the crescent slit is made. The shape of the crescent keeps the fruit from crushing the egg or larvae as the fruit grows. When the egg hatches, a tiny little white maggot-looking worm is born and tunnels into the seed pit. It feeds on the seed as it (the larvae/worm) grows larger. Soon, the fruit starts to turn colors and soon it drops off the tree. Eventually it transforms into a bug and the cycle starts all over again.

The bad news is there can be several cycles in a season, so if any of your fruit managed to not get infested the first round, it will likely get hit sooner or later. Once the scar is there the fruit is a goner…in a couple weeks or so it will turn color and drop. Some say a pesticide called Imidan and maybe others can still save some fruit by soaking into the egg, but that has not been my experience.

In short, the best thing you can do is start spraying immediately and possibly you can save a few plums that haven’t been hit yet. If you don’t know where else to turn, you might go to Tractor Supply and buy a bottle of their “fruit and nut tree spray” which has both an insecticide and anti-fugal agents. Another fairly easy to find product is called Triazicide and is usually available in most big-box stores.

Good luck!


Well, i have shaken myself out of “ignore it and hope it goes away” mode. My treee seems to have multiple pests. I think it’s plum curculio and perhaps something else that makes little holes near the stem area. The leaves at the top of the tree are all chewed up (hadn’t noticed them since I’m short, but my husband saw them when we went out together to try shaking the tree).

I’m just sick at the whole thing. We are organic at our house. I’ve been reading up on surround and bagging.

I have a peach tree and pear tree very close by. I’m worried about my peach (since I so love peaches), but honestly don’t see any signs of infection. It’s been producing for many years and I’ve only had fights with the squirrels (and frankly, at this point, I would rather battle squirrels than these insect pests!!).

So so so frustrating.

Thank you for the detailed explanation on how curculio works. I was having a hard time absorbing all the information and somehow your explanation cut through my fog of denial. :hushed:

I’m so glad I could help. Perhaps one reason I was able to explain it on an easy-to-understand, beginer’s level is that it has only been a few years ago since I had no idea what PC was. Like you, I was absolutely ready to pull my hair out because I’d waited several years to get fruit and suddenly it was all dropping off prematurely. I know your pain. Deeply. I’m far, far from an expert these days and you may have noticed on another thread here that I am still having some issues with PC myself, but I think that is due to me waiting too long between sprays combined with some rain during that long (12 day) period.

I absolutely admire and applaud your goal to be organic in everything you grow. Stone fruit is possible to grow organically in some areas, but I just want to tell you right up front that it is going to take you a lot of work and a good deal of time to pull it off. But if I understand you to say you have been harvesting peaches for a few years without spraying anything, then your chances are better than I’d have thought. I’m very surprised you have this much of a problem with PC on your plums and yet have an unsprayed peach tree just a few feet away that hasn’t been hit too hard. That is just amazing and hard to understand…but I’m happy for you and hope you continue with such good luck. My fear is that you may not, though, and the next egg laying cycle they may find there way over to your peach tree…but let’s hope not.

Hope you can salvage a few plums this year and that your peaches remain bug free! Good luck.

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This is my first year with real plums and peaches, and I got hit by PC and now apparently OFM on the peaches at the tail end of my last spray. The ‘kickback’ of the emergency pesticide I used on the plums looks to have worked nicely over weeks now, but if it’s going to take that much careful spraying to fight against these bugs, I think I’d prefer to go with Surround. It’s definitely less toxic to beneficials and bees and whatnot!

You’d have to be careful after rains and spray again very quickly, but man, same with many/most of the chemicals it looks like.

Early PC hits can be “fixed” by using a super sharp razor blade and just slice them out. I did it last year with decent results. I did it again the other day. Maybe spray some calcium chloride or something to firm up the skin.

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On what fruits?

I’ve done this with success on apples

Plums… i just slice them… the smaller the better…they can heal. Scott had mentioned it a while back.

I brought in some “wild” branches in hopes of pollinating my plum tree. I think that’s why I had bug issues this year. :scream:

I actually inspected my peach tree and don’t see any issues. I’ve also done a thorough inspection of my plum tree now and see some plums without damage. They are higher up, further away from the branches that I brought in.

What!? So good to know! How early do you need to catch it? Like when the plums are quarter size?

Not sure…i think if its still reasonably small…it will have better success. Once the egg hatches, it starts feeding…and burrows deeper into the fruit…so game over at that point? probably. This was a Lavina i did it to last year …couple weeks(month?) don’t recall… after slicing Pc out


Now that is some of the best information I’ve seen in a while! And if the damage from a cut is no worse than your photo shows, that is incredible. As I’ve said, I just haven’t had much success at applying Imidan after a pc hit- even when I am 100% sure it is only one day old. I’ve read that can help (ie “kickback”) but it hasn’t for me. Your suggestion makes sense and I appreciate you sharing it!

One of the first things you need to do is to figure out if you have curculio or oriental fruit moth or both. They require very different treatments. Find a worm and put it on your hand, if it crawls in a definite direction its OFM, if it just flails about its a PC (no legs).

If you have PC they can be controlled without poisons, I find Surround (edible clay particles that irritates them) works very well. But it does require 3-4 sprays in the spring. At this point the PC is done damaging for the year so its more planning for next year if thats the problem you have.

The OFM is more challenging organically, you need to spray spinosad and/or Bt when they are exposed (around egg laying time) and it requires spraying throughout the season. Surround also helps with them. If you didn’t find it yet I made a guide for my spray schedule which gives some hints on how to use Surround.

The major problem with growing peaches and plums organically is the rots. You need to spray a whole lot of sulphur to try to control them and will still lose a good amount. It depends on how humid it is where you are though. I now use synthetic disease control sprays to deal with the rots, but I was all organic for ten years or so and found it could work with effort.