Is this PC damage? This is my first year getting significant fruit set on my nectarines, and I realize I’m probably late to the party on doing something about it.
No.it’s not PC damage.it looks like some type of disease
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How effective is Spinosad on PCs and codling moths, apple maggots? I’ve always bagged, but too many apples to bag this year. Spinosad has worked well on potato beetles and tent caterpillars be in the past. I mix Surround with the Spinosad for the pre-bagging sprays, but wonder if the Surround is redundant. Will they work all season if I spray weekly?
Looks Like thrip damage to me. It could also be some little beetle having a snack. If you don’t want to spray during bloom you will just have to accept some nectarines will look like this. You can also just grow peaches and not have this issue. The more fuzz the better (against thrips)
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Thanks! That’s good news I think. I don’t mind ugly fruit at this stage, just wanting to avoid things that will cause fruit drop like I had last year.
Excellent descriptions of the types of insecticides. Thank you so much Mark for taking the time to explain all of that.
I read and follow label directions, but I have not dug in and researched much about the details of how and why different classes of insecticides work. Or when I do, I can’t find answers to the questions I am looking for. I was questioning the efficacy of contact insecticides, and how long they persist on the leaf & fruit surface in enough strength to kill PC walking around. I read somewhere, but can’t find the source now, that contact insecticides that are available for home orchard use have very short half lives (breaking down quickly with sun exposure) and do not persist on the tree for as long as the wait period is between sprays. So basically if you don’t hit them with the spray, they won’t be affected much. And your fruit is therefore vulnerable for 7-10 days until your next spray, if you are spraying every 10-14 days. Which makes me think, what’s the point of using them? I am talking about malathion, permethrin, carbaryl mainly.
I don’t know where I read that, but it must not have been a reliable source, or I am not remembering correctly. I am not saying contact insecticides are the best choice to use, I don’t think they are for my situation, but maybe they are more effective than I previously thought. But if that is the case, then they are also more harmful to the beneficial insects. So any lady beetle, praying mantis, lacewing, spider, etc that walk around in the trees will die because they have come in contact with the insecticide residue? I want to increase beneficials, not kill them off. I am at war with the pests, but the beneficials are being killed just the same.
This is interesting, and not new information to most of you, but is something I hadn’t considered in many years. The substrate to which the insecticide is applied, also affects the half life considerably:
From National Pesticide Information Center: http://npic.orst.edu/factsheets/half-life.html
Each pesticide can have many half-lives depending on conditions in the environment. For example, permethrin (Permethrin General Fact Sheet) breaks down at different speeds in soil, in water, on plants, and in homes.
- In soil, the half-life of permethrin is about 40 days, ranging from 11-113 days.
- In the water column, the half-life of permethrin is 19-27 hours. If it sticks to sediment, it can last over a year.
- On plant surfaces, the half-life of permethrin ranges from 1-3 weeks, depending on the plant species.
- Indoors, the half-life of permethrin can be highly variable. It is expected to be over, or well over, 20 days.
Malathion
Bacteria in the soil may break down malathion and sunlight can break down malathion in the air. Malathion will mix with water and can move quickly through soil. Because of these properties, malathion can be found in surface waters such as streams, and sometimes it is found in well water. The time it takes for malathion to break down to half of the original amount in soil is about 17 days, depending on the soil type. This length of time is known as the half-life. In water, malathion has a half-life between 2 and 18 days, depending on conditions like temperature and pH. Malathion vapor may also move long distances in air or fog. From another source [Bradman MA, Harnly ME, Goldman LR, Marty MA, Dawson SV, Dibartolomeis MJ (1994). Malathion and malaoxon environmental levels used for exposure assessment and risk characterization of aerial applications to residential areas of southern California, 1989-1990. J Expo Anal Environ Epidemiol. 4:49.]: The half-life on plant surfaces is 1 to 7 days.
Carbaryl
At soil and water surfaces, microbes break carbaryl down quickly. Half-lives are 4 days in water and 16 days on soil surfaces. Sunlight can also break carbaryl down. When carbaryl was not broken down by water but was still exposed to sunlight, a half-life of 21 days was reported. Carbaryl has a moderate ability to dissolve in water and migrate through soil toward ground water. Deep down in soil, where oxygen is absent, carbaryl breaks down more slowly. A half-life of 72 days has been reported. In water and soil, carbaryl has a low potential to make vapors into the air.
When carbaryl gets on leaf surfaces, very little is absorbed into the leaf. However, carbaryl is more readily taken up by the roots and moves to areas of active growth. On leaf surfaces, a half-life of 3.7 days has been reported.
I read this article last week and was wondering what your thoughts were on the statement that organophosphates (malathion being one) can provide curative action up to 2 weeks after eggs are deposited. From Michigan State University:
(Effectively controlling plum curculio in stone and pome fruits - Fruit & Nuts)
There are many insecticides available for control of plum curculio, but their performance characteristics vary greatly compared to our traditional broad-spectrum chemistries. Conventional insecticides, such as organophosphates and pyrethroids, work primarily as lethal contact poisons on plum curculio adults in the tree canopy. Avaunt also works primarily by lethal activity, but ingestion is the important means for delivering the poison. Neonicotinoids are highly lethal to plum curculio via contact for the first several days after application, but as these systemic compounds move into plant tissue, they protect fruit from plum curclio injury via their oviposition (egglaying) deterrence and anti-feedant modes of activity.
The rotation of these two modes of action is critical to successful plum curculio control. Avuant needs to be used prior to any neonicotinoids because Avaunt must be ingested to work effectively, and the neonicotinoids have that anti-feedant characteristic. If needed use Avaunt first followed by neonicotinoid insecticide. Neonicotinoids and organophosphates (OPs) can also be used as rescue treatments because they have a curative action that can kill eggs and larvae that are already present in the fruit. If plum curculio infestation occurs and a rescue treatment is needed, organophosphates and neonicotinoids can provide curative action up to two weeks after plum curculio infestation, although in some cases dead cadavers can still be found in fruit. Growers should not rely on this curative mechanism for most effective plum curculio control.[Controlling Plum Curculio]
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Yes, I did mean Imidan. Sorry, hands typing faster than brain. Thanks for the heads up. I corrected my post.
Most contact insecticides are indiscriminate. They have a broad spectrum and will kill predator insects along with pests.
In my case, if I want to kill stink bug, I have to kill predators. If one wasn’t worried about stink bug a systemic or translaminar would probably be easier on the predators. Something like Actara or Avaunt would be easier on predators than a non-systemic contact insecticide.
Not that you won’t kill some predators with Actara or Avaunt, but it would be less than something like permethrin.
Most pyrethroids like permethrin don’t last a super long time. The problem is generally they don’t like heat and UV. Because of this issue Syngenta developed Warrior II (same active ingredient as Warrior - Lambda cyhalothrin) but with micro encapsulation. They encapsulate the active ingredient in something that protects from UV. Sort of a slow release, as I understand it.
Carbaryl is the same way, but even shorter half life on trees. Bayer developed Sevin XLR (stands for extra long residue). I don’t know how Bayer made it degrade slower, but apparently they did. The Sevin XLR is sold in 2.5 gal. jugs, enough for about 3 acres of peaches for one spray. So it would take a long time to use up with just a few trees.
Nufilm 17 spreader/sticker advertises their product microencapsulates with UV protection. Some people like Tactic. I’ve used both, as well as Latron B 1956. Who knows which one is best, but I will note that Nufilm 17 is the gooiest and hardest to wash off the tank or your hands. Based on this, my opinion is that Nufilm is probably the best. Right now I’m using Cohere (Helena Ag). They claim it also has a UV blocker, does not require sunlight to set, and will allow locally systemic (translaminar) products to penetrate leaf surfaces.
Again who knows which one is best? All the manufacturers make it sound like they have the best product. I think it’s safe to say, some brand of sticker/spreader is better than none.
For stuff which is subject to UV degradation, it’s probably best to spray as the sun is going down. There was someone on this fruit forum who successfully used Malathion for major fruit pests. He said his key was spraying at night.
I don’t quite think Malathion would allow 2 weeks curative action. In fact, I doubt Malathion would provide any kickback.
I suspect John Wise was referring to Imidan when he mentioned 2 weeks kickback. And possibly Azinphos Methyl (Guthion) which is no longer registered with the EPA. These are very powerful insecticides (especially Guthion) in which a very small amount is required to kill PC. I don’t think Malathion would be on the same level of lethality to PC, as Imidan or Guthion, even though they are the same class of insecticide (1B organophosphate).
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It has no efficacy for PC. For moths it puts a dent in the population but is not a complete control. I use both spinosad and Surround as neither is completely effective but I still get a good crop.
I also use Venerate, Grandevo and Madex. Something happened to my PC this year, they were strong early on but faded fast. Hopefully I can repeat next year…
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Mark, thanks again for sharing your wisdom.
Choosing the best insecticide, or the one that causes the least collateral damage and still kills the bad bugs, is not as straightforward as I once presumed it would be. I’d like to do the least amount of damage to the beneficials, so based on what I have read here and questions you have answered for me on another thread, I still think Actara or Avaunt would be the best choice for my situation. I didn’t want to spend the money for it this summer, since I still have several contact insecticides on hand I decided I should use up.
I haven’t tried Surround yet either, and don’t know if I would like that, how well it would protect, and if I could keep up with sprays if we had a wet spring. I would have to get a different sprayer with an agitator, but I guess I shouldn’t rule out Surround, as many members here use it with some success.
I do use a sticker, but haven’t tried any of those that you mentioned. I’m using what we keep on hand for when we are spraying noxious weeds but can’t recall the brand name right now. It’s probably worth getting one that advertises that it microencapsulates.
OK. Even though he mentions organophosphates, I thought that sounded a little too good to be true. As you state, it probably does not have similar killing or kickback power as Imidan or Guthion.
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Just wanted to mention, in case you weren’t aware, if you do choose to use Surround, don’t use a sticker with it.
Apparently it’s just about impossible to wash Surround off fruit, if a sticker is applied with it. Plus it possibly makes the Surround less effective.
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Thank you for that reminder. I do recall reading that. 
I have quite a few people asking me if they can buy apples, peaches, cherries, pears. I don’t know what their reaction would be to fruit with clay on it, and I don’t really want to have to wash all the fruit before selling either. This year will be small harvest on all these fruits I think, so I probably won’t be selling much, if any. If I choose to try Surround next year or the future, I suppose I need to take appearance into consideration.
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Great info about not using the sticking agent.
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How effective would Sevin or Permethrin dust be, applied in the evening with a duster (like a rose duster)?
I just found some fruits on a peach and an apricot tree that I had thought were blank. When I sprayed 2 nights ago, I thought they were blank and did not spray them. Since it’s so few number of fruits, I wonder if I could dust them to keep the PC at bay until the next spray. I don’t want to mix up a small amount of spray.
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June 2023 is my second season using Avaunt (indoxacarb) to control curculio, moth and maggot fly.
This early in the season, and this year same as last, my Mt Royal plums and my apples are incredibly clean in an orchard that would show curculio strikes when I was using acetamiprid (the now-discontinued Ortho Flower Fruit and Vegetable Insect Killer Concentrate).
My extension person warned me that Avaunt is “much less effective on late season pests”, which in my case is the maggot fly, and last year, my fruit developed corky inclusions that I was told on another thread was the result of maggot strikes, not bitter pit. I tanked mixed some of my remaining acetamiprid last season, and the Avaunt label says you can do this, but I missed a late-season spray for another flight of maggot fly on account of being rained out.
But for curculio, Avaunt has been effective for me. I have a 1/3 acre orchard with 25 trees that I cover with 18-20 gallons of spray mix, and I apply Avaunt at the rate of 2.5 grams/gallon. I measure out the soluble granules, on site in the orchard where I mix my spray, using one of those low-cost digital scales. This is equivalent, roughly, to applying 6 ounces per acre recommended by the label, diluted in 60 gallons of water, at the lower end of the water rate on account of using a hand-pump sprayer.
I use a 3-gallon hand pump sprayer–I get my exercise that way. Fill one gallon of water, pour in 7.5 grams Avaunt granules, pour in a second gallon of water, add any fungicide or other the acetamiprid liquid, close the top and give the sprayer tank ten vigorous shakes, open it up, pour in the third gallon, close it up, give five more shakes and pump it up. To maintain agitation of the granules as recommended, I give another five shakes each time I pump the tank to build back spray pressure. I end up with very little residue when the tank is empty.
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@PaulInMaplewood , thank you for the details of your experience with Avaunt. I am glad to hear it is working so well for you! I also appreciate the mix rates you shared.
How old are your trees? Do you have mature orchard? You say you spray 18-20 gallons on 25 trees, and that sounds like a lot to me. Or perhaps I am under-spraying.
I need to compare Actara vs Avaunt and make a decision for next year.
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I paced out the plot and measured it to be about 1/3 acre. It is a fenced area behind the two barns on the property. Instead of the fence keeping livestock in, the fence is intended to keep deer out, which it does some of the time.
The 25 trees are a mix of standard, semi-dwarf and dwarf trees. One of the larger standard trees may get as much as 3 gallons of spray, a semi-dwarf a gallon and the dwarf trees maybe 3 to a gallon. By that calculation, you see how I get to 18-20 gallons for that number of trees.
The first trees were planted in 2003 or 20 years ago. My wife spotted one tree the size you get from the home product store but growing wild. I think it sprung up from Cortland that my parents would purchase from a neighbor growing apples for sale, where they may have dumped the apple cores on this plot before my wife and I acquired the property and developed this plot into an orchard with my Dad’s help. This sprawling tree by a stroke of fantastic luck bears one of my favorite apples, large tart and crisp for fresh eating but cooking up into a delicious red-tinged syrup when baked. Too bad these apples only keep until about Thanksgiving. This is a three-gallon tree whereas a sprawling Honey Gold planted in 2003 is a two-gallon tree.
The label instructions say to spray to the point of runoff. I spray to the point that the leaves are visibly wet. On a larger tree, I have pruned “lanes” to access the interior of the tree to aid both spraying and getting a ladder inside the canopy to pick upper branches. With the hand-pump tank sprayer and entering each lane, I spray the tree from the interior of its canopy because the instructions are to get the underside of the leaves, too. I back out of the canopy, pump up the sprayer, unscrew the nozzle for a narrow stream, and then spray the upper branches. I then screw the nozzle for a broader stream, repump the sprayer, and circle the tree, from the “sight picture” making sure that I wet each branch from where I am standing, repeating this as I take up positions around the tree.
Although my spray rates in terms of liquid volume and pesticide dilution may seem like guesswork, I teach engineering as my day job, and the practice of engineering can involve making reasonable approximations. 50 gallons per acre is at the low end of the fluid volume on the product label, but with the hand-pump sprayer, I am going to apply a lot less fluid than someone with a power sprayer.
Of the three pests I control–curculio, moth and maggot fly–Avaunt is labeled for all three and it is labeled for plum, apple and pear that is in my orchard. But the label warns that it may be less effective on maggot fly, especially if there are untended apple trees on the property, which there are, from which adult maggot flies could fly to the orchard and start egg laying without feeding first in the protected area.
One should check the label on Actara, and I recall that it is not labeled for maggot fly although the Web site of a the University Extension of a neighboring Great Lakes state indicates that Actara is highly effective on both moth and maggot fly–its effectiveness on curculio is a given as indicated by comments here on Growing Fruit.
I emailed the professor who offered this advice and as diplomatically as I could asked whether one was breaking a Federal law to apply Actara against maggot fly. Being in the education biz myself, I am trained on the importance of following the rules.
The answer I received was so long as you have one of the labeled pests in the orchard at the time you spray, “oops, this stuff happened to kill the maggot fly, too, just so bad for Ms. Maggot Fly who just happened to want to lay eggs at that time” is OK.
Hope this helps, but I will answer any follow-up question as best I can.
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Glad Avaunt worked well for you. How many times did you spray? We are indifferent zones so that would change spray schedule. I’m in zone 7. Used Imidan 3 times this year. Twice in May and once in early June. Should have sprayed earlier in May since there was some damage prior to spray. Total Curculio damage hasn’t been bad this year. I had some hits but after normal thinning I have mostly clean peaches and plums.
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Paul thank you for the detailed notes. If you have any pictures of your setup I’d love to see it. Especially your “lanes”. Most of my trees were so mangled by deer in their youth that their structure is more “free form” than anything else but knowing what I know now I’m hoping to get a better structure built into my whips.
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With respect to Avaunt, I did three applications: 1) “cover” at petal fall in late May, 2) a second spray 2 weeks later when my extension station reported "a heavy flight of codling moth, and 3) a third spray when I spotted maggot fly the third week in July. The extension station reported more maggot fly activity in mid August, but I didn’t spray on account of weather. Or being lazy.
This year I applied a spray to the plums, only, their petal fall, a second spray of the plums and a first spray of the apples two weeks later when the extension station was warning of a heavy flight of moth.
I am hoping to hold off spraying for maggot fly until 3rd week in July when I hope to be no longer under lifting restrictions from a hernia repair – there is no good time to schedule an elective procedure. I may apply a fourth spray in August if the extension station warns of a late “flight” of maggot fly.
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This is the sprawling Honey Gold I mentioned above. It looks like chaos, but if you saw the tree in-person and in 3D, you would see the “lanes” between major branches where I can get a ladder into the canopy.
This is supposed to be a “modified” or “distributed” leader I learned about in the University of Wisconsin-Madison Extension pruning class.
It is one of the few trees in the orchard this season without much fruit on it. It could be that I stressed the tree pruning it during a mid-winter warm spell that was followed by sub-zero lows. It didn’t put out many flowers.
Yeah, yeah, “don’t do that”, but I am falling behind in the late-dormant in this orchard!
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