PC - Mother of all stone fruit insect pests

I must be doing something right. All my cherries have been sound. Today I happened to notice a PC scar on a Methley plum, but it was healed over and the fruit still growing green - almost certainly no living larva inside.

Every drop I’ve opened [mostly apricots] has been larvae-free.

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I have used Endigo which is a combinaion type product but with thiamethoxam and lambda-cyhalothrin when the petal fall spray did not get the job done. I have tried Imidan, Avaunt and Actara as a petal fall spray. They all worked pretty well and I can’t say for sure which one worked the best.

I don’t think it would be necessary to mix multiple products with different modes of action together to get the PC.

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You are so lucky. Most of my plum, apricot scared by some insects. Definitely have worm inside. However, many of A.pears have insects bite mark too, some are deformed. but no any worm inside!

As a premix, Voliam Flexi would not be an optimum choice for PC imo, since only the Thiamehoxam component would be effective against PC and you would be paying for a pre-mix component which has no activity against PC (Chlorantraniliprole).

If you want to tank mix your own insecticides to try to get better control, you might consider products which all the active ingredients in both products specifically target PC.

If trying to keep prices at around a hundred bucks, Actara sells for $105 for 30 oz. in the catalog I’m looking at (Keystone sells it for $119 Actara Insecticide - 30 Ounces [100-938] - $129.95 : Keystone Pest Solutions, Low price herbicides and pesticides). You could mix that with one of the products you mention (although I probably wouldn’t mix it with an insecticide of the same class, like Imidacloprid).

As a follow up to my original post, I still haven’t found any fruit with a larva inside, so I think that although some eggs were laid in smooth skinned fruits, I haven’t found any egg/larva which survived.

I think with any insecticide it can be tough to prevent egg laying because the adults are hard to kill and continue to emerge from wooded areas around the orchard. But some of these products have good ovicidal/larvacidal activity.

Do you get OFM where you are? I’m too far north for it. Unless the BMSB start causing trouble PC is my only serious pest of stone fruit [except for JB]

This is an important topic and time to continue it for 2019. Anyone having success with stopping PC damage without using a sticker?
Last year I used Triazicide with a sticker 5 times up until July 19th. In May and June there was rain several times a week. Either the sticker didn’t help or Triazicide (Gamma-Cyhalothrin) doesn’t work.

I go with the “triazicide doesn’t work” theory

I hate PC , they are my main pest here , I’m hoping the complete lack of fruit last year put a damper on their population.

Heres my experience with pc on my peach tree the last 3 yrs:
Year1: first year flowering. no spraying. Noticed bites and jelly just after shuck split. All fruitlets disappeared over the next few weeks. I was clueless or in denial, but in hindsight it is clear that pc got everything and the fruits dropped into my leaf mulch never to be seen again.
Year2: again noticed jelly on most fruitlets early on. I then sprayed surround several times. I looked carefully in the leaf litter and found many many drops, nearly all had a pc larva inside. I end up harvesting maybe 5 non wormy fruits.
Year3. Sprayed permethrin and nufilm at petal fall and again 10 days later. I have a couple hundred perfect looking ping pong ball sized fruits hanging on the tree and have not seen a single curc bite. I have not sprayed in over a month.

I dont have an unsprayed control tree but it seems improbable to me that i am looking at natural variation rather than a very effective spray treatment. Hopefully i dont get nailed by generation 2 or late emerging pc. I am concurrently seeing more damage than ever before on my apple tree on the other side of the house. Crazy.


I have been using Ortho Flower Fruit and Vegetable Insect Killer Concentrate (32 oz of .5 percent Acetamiprid, a neonicotinoid) – to control the three orchard pests PC, CM and AMF. This is the same active ingredient as Assail. I just found out in response to an e-mail inquiry to Scotts-Ortho that they discontinued this product as part of their program to remove the “neonics” from their products. I guess they have to respond to their public, even if EPA isn’t making them do this?

After several seasons of use on a mix of plum and apple on my 1/3 acre orchard in Door County, WI, I used to spot PC weevils and adult apple maggot flies in the orchard, but not any last season. I am spraying twice a year now, once at petal drop fruit set, a second time during maggot fly season.

I am still seeing pokes on Mount Royal plums that exude a clear white crystalline sap, but I am not getting heavy fruit drop as before my spray program. Are these pokes the result of oviposition strikes?

2018 and 2016 were wet years with heavy crops that saw a lot of loss to brown rot, which I am trying to control by removing affected plums from the tree, getting on my hands and knees, wearing heavy nitrile gloves to not get poked by wasps and picking up what falls, and by alternating Captan and myclobutanil – lost about a third of the crop but what remained on 3 trees was enough to fill the freezers of 4 families. I am wondering if the PC strikes are providing an entry for the fungus infection?

The advantage of the neonic Acetamiprid (Assail) is that 1) studies claim that it is much less persistent than other neonics and that it is not bee toxic, 2) it is curative – kills the PC larvae even after the fruit is poked 3) Imidan is supposed to be curative in this way, but it is much more human-toxic? I wear a jump suit, gloves, a respirator with an organic vapor cartridge, and I strip in the garage and take a shower after application, but still, I prefer an alternative to a strong organophosphate.

Pyrethroids of different formulations is what you see these days on the shelves of the home-product and gardening stores, and posts above about their lack of effectiveness is worrisome. The only other Acetamiprid formulation labeled for fruit trees and for my state is Assail, which costs about $600 and contains 120 times the active ingredient as the $15 bottle of the discontinued Ortho product, which lasts me a season.

I can buy the neonic Actara in a 30 oz of 70% concentration for $150 dollars. The cheapest product from the Door County Coop is $66 for 5 1-pound packets of Imidan. Tristar is a liquid formulation of Acetamiprid, but my Coop guy tells me it is not labeled for fruit trees.

I know of home/hobbyist growers who break open and share those packets of Imidan 70 WP, but the whole point of the packaging is that a commercial grower is supposed to toss that water-soluble “brick” into their tank and not have to come in contact with that organophosphate in its concentrated form. My Coop guy will sell me that, but do I want to start measuring and mixing it in 70 % wettable powder form?

My Coop guy will sell me Avaunt, but he says that the commercial orchards in my area don’t use it.

To sum up, help!

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I use Imidan in smaller sprayers. Wearing chemical resistant gloves, long sleeve shirts, outside on non-windy day I will open one of the 1 pound pouches and put the contents in a sealed, water resistant, humidity resistant plastic ammo container. The ammo containers seal tight enough that they keep the Imidan smell/stench inside of the container. I use a metal measuring spoon to load into the sprayer. The remaining unopened, sealed 1 pound pouches of Imidan I store in a separate Ammo container. The Ammo containers can be locked with a padlock if you have children. To my knowledge I am not inhaling or getting Imidan on my skin following this process. I have no issue using Imidan other than it is not as a effective as Permethrin (per University study) after a rain. I use Permethrin on peaches, I would not use Permethrin on apples.

I looked at Assail (commercial version) sometime ago, and if I remember correctly it is to concentrated to use in smaller sprayers. The per gallon rate was so small it would be difficult to mix. Somewhere in one of the threads I think there is a discussion about Assail/per gallon rate.

You do not mention what type of sprayer you use but I assume it is a small unit if you are growing on 1/3 of an acre.

I use Lambda-cyhalothrin a pyrethroid and it works fine for me. I alternate with malathion. I have zero PC although you see strikes, the fruit is not infected.
The product with L cyhalothrin is Bonides Fruit Tree and Plant Guard. It also has a fungicide Pyroclostrobin and Boscalid which are extremely effective against brown rot and it uses a different mode of action than Infuse, so using both you’re fighting the brown rot war from 2 sides. outflanking it :slight_smile:

I don’t have any brown rot either.

I can’t say this will work for you, maybe pressure is less here for PC?

Also something really important about Pyrethroids. They are not stable and break down with heat. Buy your Pyrethroid in the winter!! You want fresh product, so I buy from Amazon, I know it’s not some bottle sitting 2 years in a retail store.

I also have some Ortho Flower Fruit and Vegetable Insect Killer Concentrate. I’m going to look for it on retail shelves from last year. I only have enough for one season. Sometimes I use it instead Malathion. But only last year, I didn’t know it was that effective, thanks for that info! Bet I can still find some!

I am not too surprised Ortho is going to stop offering a neonic for home use. Too bad because the ORtho Flower,Fruit and Vegetable Insect killer worked great. Kills Bees? Who would be spraying apple trees with an insecticide when they are blossoming anyway?

Paul-in Maplewood: I just ordered some of the above product from amazon two weeks ago. Check with them. I see the container changed as my last one had the measuring cup as the cover and the new one sent has no measuring device. I will have to use my liquid ounce measuring beaker again.

I too use Imidan 70 also. While acetamiprid is great, I prefer to use Imidan early in the season for better PC control. I am greedy and prefer not to share my fruit with the curculios.

No experience with avaunt bit sorry to hear about ORtho not offering a great product. Imidan is great but not good for my sweet cherry nor my Haralson apple (causes russeting).

Perhaps I need to go back on Amazon and stock up on Ortho’s product while they still have it in stock. I presume it would keep for years?


Wow your source on Imidan is cheap! I know with shipping I paid about $95 for 5 pounds last year. Maybe I better start going back to door county on my vacations so I can buy cheap Imidan. Good excuse to pick cherries again at lautenbach’s orchard too. And sample their delicious pear wine.


I can tell you’ve paid attention to the forum. Your post shows you are familiar with what you are writing.

Just some thoughts:

Assail isn’t super great on PC, compared to some of the heavy hitters. I’m talking about heavy PC pressure here, not light backyard pressure (depending on location).

Belay, Actara, Imidan are generally recognized as more of a big fist against PC.

Your prices from suppliers are a bit high. Perhaps here are some which might do you some good.

I ordered some Actara this spring from Deerfield supplies. A 30 oz. bottle was $109. If you order before March 22, there is an 8% discount. That pretty much pays for the shipping. There is no sales tax outside of KY.

A 64 oz. bottle of Assail (30 SG) runs $247 without the discount.

I don’t use Imidan (because it’s expensive). But it sells for $67 for a 5 lb. pack.

Any insect damage is going to increase the risk of fungal disease. Just like if you scrape your hand increases risk of bacterial infection. Open the protective covering = increase the risk of infection, whether by insect, or mechanical damage.

Btw, you are way more careful with your tyvek suit for mild pesticides than just about anyone. I just sprayed this morning and wore all the required PPE. Still blew pesticide in my face and covered my person.

Around here we dip our finger in the tank and touch the tip of our tongue to measure the strength of the spray tank. Gives us protection against deer ticks :wink:

I’m kidding of course.

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I also wondered about the shelf-life of insecticides and especially the Ortho product. The best thing is to check the label if you still have the bottle.

As far as stocking up, something tells me the bottle without the measuring cup is the older packaging – Amazon is out of the one with the newer packaging with the screw-in measuring cup.

I just order some of the Ortho product from SeedWorld Ortho Flower, Fruit & Vegetable Insect Killer Concentrate - 1 Qt | Seed World.
They have a great price but they charge more for shipping.

I will have to see if they ship rather than tell me, “Sorry, out of stock.”

Thank you for the encouragement and thank you for the leads.

I joined a Chicago-based group called Midwest Fruit Explorers http://midfex.org/ about 4 years ago, learning about grafting and pruning from their hands-on “clinics.” Many of the members are professionals in other disciplines, and I got tips on handling insecticides from a retired university professor who studied diseases in poultry. I also have benefited from contact with members of University of Wisconsin Extension who are dedicated to serving the whole range of growers and are eager to help.

Even with the PPE, it is easy to get droplets on one’s exposed face. I think the best thing to limit exposure is wash/shower real good afterwards.

A quality org. Like several folks here, I was a member of Nafex over a decade ago. As you know Midfex was an offshoot of that. In my more enthusiastic days, I read about 10000 Nafex posts archived before I joined. I wish I could remember all of what I read, lol.

I think your local WI experts are a valuable resource. The truth that’s frequently mentioned here is that all fruit growing is local.

Just be aware that some local “experts” really have little experience with fruit. More often than not, the experts are in disciplines unrelated to fruit and “fake it” some when it comes to fruit.

In that sense, it’s good to evaluate the advice of the local experts against some of your local folks (WI natives) on this forum, even if they aren’t pros.

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when I learned Ortho was discontinuing the product, I picked up a couple of bottles late last year

Imidan works great on PC but has several label restrictions I have not seen on any other chemicals that I use:

 Do not authorize any person who is not covered by the Worker Protection Standard (WPS), such as members of the general public involved in “pick-your-own,” “U-pick,” or similar operations, to enter a treated area for 14 days after application of this product.

 For groundboom and airblast applications, do not apply this product within 25 feet of (1) buildings occupied byhumans for residential, commercial, or business purposes, including but not limited homes, farmworker housing, orother residential buildings, schools, daycare centers, nursing homes, hospitals, and (2) outdoor recreational areas such as school grounds, athletic fields, and parks. Non-residential agricultural buildings, including barns, livestock facilities, sheds, and outhouses are not included in this prohibition.

I don’t understand the significance of these restrictions but I follow them. A 14 day re-entry period for non farm workers seems like a long time.