Plum Curculio


Sevin is no longer the Sevin that you know, it used to have carbaryl (which is a carbamate) as active ingredient, but now it has been replaced by a pyrethroid or a couple of them.


That is interesting and surprising. They should just have named it something else- but that’s marketing for you.


Ahmad & @ltilton How long does does malathion smell? Like a couple days before its bearable, weeks?


Like a couple of days. But you have to use it every couple of weeks to get any good of it


Extensive for plums, moderate for peaches. The peaches have some other minor insect problems.


If you want something with low mammalian toxicity, Actara is probably tops. It has good kickback for PC. I’ve used it as a rescue spray more than once. Although it provides excellent PC control, it has virtually no effect on stick bug (but most backyard growers don’t mind catfaced fruit).

It’s a neonic and very hard on bees. That said, I’ve used it for years and have a neighbor with two hives right next to my fence. Gave me a bear of honey just the other day from the hives.

Actara comes in commercial packaging, so if you purchased a bottle, it covers about 5 acres. So it would be a lifetime supply for a backyard grower. The cost isn’t bad.

This site sells it for $130/bottle. It’s a water dispersible granule, so I would expect the shelf life to be measured in decades, perhaps centuries, if stored properly.

It used to have “For agricultural Use Only” on the label. But I don’t see it on the label now. Perhaps they changed it, or I missed it when I looked at the label just now.

You just need one good PC insecticide. You don’t have to rotate. Resistance issues are really for commercial growers. I don’t recall ever reading a homeowner insecticide label which discussed insect resistance.

Imidan is good on PC (also poor on stink bugs). Like all organophosphates, it stinks. Generally speaking organophosphates (imidan, malathion, etc.) have a higher mammalian toxicity. The EPA has been phasing out organophosphates (either by limiting uses, or outright bans) for about the last 30 years. Parathion was one of the first banned. Lorsban is the next one on the chopping block.

Imidan comes in water soluble packets designed not to be opened and thrown in the mix tank. This is for applicator safety. The packets are designed to be mixed in 100 gal. of water. Should you choose to use Imidan, and open the packets, be sure to use a respirator when mixing, or at a minimum very careful not to breathe the dust.


Hi Olpea,

This may be a repeat discussion but looking at the label the spray rate is 4.5 to 5.5 ounces per acre for PC on peaches. To make it easy lets assume 5 ounces. I think I remember you mentioning that you plant about 97 trees an acre (is this real or did I imagine it). Again to make it easier lets assume 100 trees per acre. If I am a back yard grower with 10 trees than I should spray 1/10 of 5 ounces or .5 ounces for 10 trees. Not sure what the mixture rate would be per gallon. Assuming a professional sprayer was using a 100 gallon tank that the ration would be 1/10 of 100 gallons = 10 gallons. I usually get they spray logic wrong when I try to figure it myself but long story short you are going to be putting a tiny amount that may be hard to measure in a 4 gallon backpack sprayer. Did I get this roughly right or did I get my estimation way off?



Spud, you are right. At 100 gal/acre spray solution, I use the 5.5 ounces per acre. That translates to 0.05 ounces per gal. 4 gallon backpack would take 0.2 ounces. If Actara were a wet formulation, that would be 1/5th of an ounce, or a tad more than a teaspoon. Because it’s a dry formulation, it takes a digital scale to measure it.

I’ve sprayed stuff like that before with a backpack. I have a couple small digital scales I use to measure the pesticide.

Lastly you want to make sure you are using about a gallon of spray solution to cover a mature tree (very light spray). If you are using 2 gallons of spray solution to cover a tree, cut the dosage rate of insecticide/gallon of water in half.


A lot more than that here. It only kills them for a couple of days.


Then you get the stink continually


… but, if you’re lucky, you get all of them already on the premises at once. Maybe then your codling moth cover sprays will take out the newcomers later. I think of PyGanic (Pyrethrin) as the nuclear option against plum curculio on apples in spite of its short effective duration. Pick a warm night for application just after petal fall.


The problem is that they don’t just come from the area they were the year before. They travel many miles and can show up in an orchard at any point from petal fall until almost 30 days later here.


I wish it could be as easy as you said. PC pressure may not be as high where you are. I’ve monitored their flight and night time temperature.

In my experience, it is not at all easy. Like @alan said, PC do not just show up one or two nights and leave.


They do tend to have a peak migration period though which is around bloom time. While more will show up after petal fall you can get a good chunk of them at that point if you lay down a poison. I am only using Surround so I get to watch them move all over for a month.


Over the years I’ve seen them come at different times from petal-fall until about 3-4 weeks later. I’ve never seen them on blooms. I get to see them because I use a bare bones program. I’ve also had people either ask me to spray late or stop after a single spray for various reasons.


I am more going by studies I read, I also don’t see many until the fruits are big enough. But I notice a lot of them hop on the earliest fruits that get big enough, making me think they are already in the orchard chilling out until it is time. If I was spraying poisons, hitting my apricots right after shuck split I could really clean up.


Same here. Apricots set fruit first, and right away the curcs are on them while apples may not be in bloom yet.

People who were going by apples thought they weren,'t out in the orchard yet.


If you get the time, please share. I’ve never read anything about possible plum c. control with only early measures (within 2 weeks after petal fall). The literature I’ve read over the years actually seems to exaggerate later threats compared to my own experience. I was surprised that I could get by with only two sprays based on commercial guidelines from Cornell, although I had Prokopy from U.Mass to provide me with hope back when I began using a 2 insecticide spray approach almost 25 years ago.

You may have seen some more recent research I’ve missed. By now, I’m relatively running on momentum, although I keep an eye on research. There just is so little on low spray approaches. Prokopy was the only researcher I’ve heard of that worked so hard on reducing the need to apply pesticide to control PC. I wish he had managed to develop a poison lure as he attempted.


To be clear, I’m not suggesting any particular spray program only that an early spray will get a bunch of them. I currently don’t spray poisons at all and have no experience to call on.

If I were to spray a poison I would optimally do it a day or two before the fruits get to curc size… so hit the apricots right after shuck split, hit apples as soon as all petals gone and gotten a bit bigger, etc.


The NEWA weather stations have pest forecasting models, including one for plum curculio–that way you can target your spray to have the greatest effect on the most generations.

Recent Plum Curculio thread