Need urgent advice on Plum Curculio spray

I have been using Triazicide for several years having been encouraged by this group.
I have serious scars most years. This year I have scars before all of the petals fall off!!
Anyway, I sprayed Triazicide yesterday with some petals still on the tree.

Today I learned that I have more scars that I thought. I am mad and want kill them.

I can spray again soon with Triazicide, or I have Malathoin, and I still have Sevin(carbaryl kind).

The internet search says that Sevin is more effective, however I have heard that I might thin the crop.

I have so many apple I will have to thin most of them so the Carbaryl thin might not be a bad thing.

Your thoughts are appreciated. soon, I am going to Spray something yet today… weekend is when I have to work in the orchard and another week will have every apple scarred.

Edit:: and Permethrin is also a choice.

So a vote:
Carbaryl ?
Malathoin ?

lol :slight_smile:


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Next year I would try Surround. The white kaolin clay powder. It really works. But it is used after petal fall. Are you using a sticker with your Triazicide?

If you want Sevin, you need to look for a new Sevin with the main ingredient of zeta cypermethrin. It sits side by side with the old Sevin at Lowe’s andHome Depot.It is effective.


Standard advice is to use different chemical controls from time to time to avoid buildup of resistance in the target insect population.

Malathion is a very old organophosphate (OP), which is still worth considering IMNSHO.

Permethrin is a synthetic pyrethroid similar to natural pyrethrin or pyrethrum (PyGanic, Pyrenone). These are not long-lived insecticides. Their potency wanes rapidly after application. They may be effective for a day or two. As such, they can be applied at dusk on the first warm evening after petal fall for control of curculio which are migrating into your orchard without severely impacting daytime polinators. (Obviously, this has already occurred in your location.) You should be able to control a large portion of your infestation (but probably not all) with one application. Upcoming treatments for other insects will have to take up the slack.

Carbamates are broad spectrum insecticides with a similar mode of action to the OPs but less toxic to humans. Several carbamates are systemic, meaning they can be absorbed by the plants. Carbaryl … has plant growth regulator activity and can be used to thin apples. Many carbamates are highly toxic to predatory mites and should be applied carefully (McCamant).

Carbaryl (Sevin) applications made within 30 days after petal fall have a pronounced thinning effect on most apple varieties. Sevin does not thin pears. It is a broad-spectrum material that acts as a stomach as well as contact poison and controls various fruit insects, including organophosphate-resistant pests such as white apple leafhopper. It is one of the low-hazard insecticides and can be used up to one day before harvest on most fruit crops … in home orchards. Sevin is very toxic to bees and, therefore, should not be used just before bloom. It is also toxic to certain predator mite species (Cooley et al.).

This is from the label for a brand of carbaryl, concerning thinning apples:


Apples Only, for Fruit Thinning


Apply 1 to 3 quarts per acre of PROKOZ SEVIN SL between 80% petal fall and 16 mm fruit size. Use the higher rates on hard to thin varieties at the early timing which is the 80% petal fall to 6 mm fruit size. Use the lower rates on easy to thin varieties and at the later thinning period which is the 10 to 16 mm fruit size. The rate to use per acre will depend on varieties, tree size, row spacing, weather conditions at the time of and following applications. Consult with the local fruit thinning experts in your area for the proper rate to use under your conditions.

The optimum spray gallonage will depend on the tree size, planting density, row spacing and amount of foliage. Use sufficient spray volume to insure adequate coverage (100 to 400 gallons/acre). Avoid spray to the point of runoff. Reduce spray coverage to the lower portion of the tree since overthinning may occur here.

Factors such as climatic temperature, high humidity, frost, tree age, variety, nutrition, previous crop, pruning and bloom may influence fruit thinning results with the product. Exercise caution to avoid possible overthinning. For the most effective results, apply under good drying conditions and when daytime temperatures (°F) will be 70 to low 80’s for the following one to three days. Application with daytime temperatures in excess of 80° F may result in overthinning.

PROKOZ SEVIN SL may be mixed with other fruit thinners, however, use caution to avoid overthinning and other adverse effects. Consult with local fruit thinning experts in your area for recommendations. Refer to the other product labels for specific use directions.

Consult with local fruit thinning experts in your area for advice on the proper use of this product on your varieties under your growing conditions.

CAUTION: The use of PROKOZ SEVIN SL may result in fruit deformity under certain environmental conditions. Before using on any variety of apples, the user must weigh the risk versus benefits when using this product, particularly when using between 80% petal fall and 6 mm fruit size. Red Delicious are more sensitive to this phenomenon and in particular, the varieties Bisbee, Red Chief and Vallee Spur are very susceptible to conditions causing fruit deformity. Precipitation and temperatures below 65° F increases the possibility of fruit deformity. The use with summer spray oils and wetting agents may increase the risk of fruit deformity and injury.

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Thanks, I’m going to put Carbaryl out of the running. I don’t want to break anything.
I didn’t spray yesterday but I’m going to soon, I don’t think my first shot got them all.

Well I used the Scientific method. I used Malathion because it stinks the most.
Maybe they will leave just because of the smell.


It is worth experimenting with cutting out the scars with an x-acto knife or something. There is even a youtube video of someone who just scrapes the scars off with his fingernail. I think the eggs hatch in 5 days, so if you can scrape them off by then, you might be good. I’ve tried cutting them in the past and have had a little bit of success. Next year I might devote a whole tree to experimenting with this. If it could be perfected, it could alleviate a lot of stress.

Good to know. I was looking for some of the old kind with carbyryl but couldn’t find the concentrate, just the “ready to use”. Maybe I’ll try the new kind if they sell it concentrated.

It says concentrated on the bottle but we still need a lot per gallon of water. If you spray 3-4 gallon, you pretty use up the whole bottle.

It is pricey that way. Mustang is a brand name but to use Mustang, you need to have a license.

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I did buy a bottle of the new stuff also. I’ve started thinning so I’ll get a better look soon.

Just throwing in a picture of the orchard to liven up the thread.


Sorry for posting in an old post but my experience contradicts what is posted here and some people are going to be disappointed if they follow some of the advice.

Carbaryl ?
Malathoin ?

I cannot speak to Triazicide. You are wasting your time with Cabaryl or Malathoin for Plum Curculio. This after losing entire crops of peaches on many trees multiple years to Plum Curculio. They just do not have enough strength to stop PC for more than a day. Currently spraying 60 peach trees.

“Permethrin is a synthetic pyrethroid similar to natural pyrethrin or pyrethrum (PyGanic, Pyrenone). These are not long-lived insecticides.”

The poster does not state what long-lived is but my experience is 10 days of protection against PC with Permethrin no rain, 7 days with rain (not downpours, sorry subjective what is a downpour). I prefer imidan but it does not last as long in the rain and is not intended for home use. 7 days may be short compared to commercial sprays but when nothing else works for the home peach grower it looks good. Here is a chart that shows efficacy length with/without rain. Rainfastness