# Study on residual control of armyworms



## Virginiagal (Apr 24, 2017)

This is an interesting article on a study of residual control of armyworms:
https://issuu.com/leadingedgepubs/docs/al-turftimes-2019-summer/s/10130518

The pyrethroid products had poor mortality rates at 28 weeks. Chlorantraniliprole was the best: " Chlorantraniliprole should provide 2 weeks of protection from fall armyworms crawling across the treated lawn, and at least 35-40 days of protection from fall armyworms and sod webworms that consume the treated grass."


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## Frankzzz (Aug 23, 2021)

Might be nice to know the application rates they used. I know it says "at label rates", but some have more than 1 rate. For example, I looked up the label for Chlorantraniliprole (acelepryn): 
https://www.domyown.com/msds/Acelepryn_Insecticide_Label_20202.pdf
and the listed rate specifically for armyworms is 2-4 oz per acre (0.05 - 0.09 oz per 1000 sf), but it also says,
"For maximum residual control or heavy pest pressure, apply at rates up to 20 oz per acre to control any of the pests listed". (0.46 oz per 1000 sf). So which rate did they use?

I would have also liked to see Imidacloprid in that comparison, too, or is the other neonicotinoid, Zylam (Dinotefuran), supposed to be similar results?


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## Virginiagal (Apr 24, 2017)

Yes, would be good to have more data, more things tested. One thing I've been trying to figure out is how chlorantraniliprole can be used by itself as a control product. Acelepyrn apparently can be used that way and it has a higher amount of chlorantraniliprole than Grub Ex. It can be a curative and a preventative. Grub Ex seems to be only a preventative and effective only on baby larvae. Scott's, however, is describing Grub Ex as a curative, though on the package itself, which focuses on grubs, it says to apply months ahead of expected invasions: https://www.scotts.com/en-us/library/insect-control/how-control-armyworms-lawn
What do you make of that? I'm not sure I can believe their claim. If you applied a greater amount of product, to match the amount of active ingredient in Acelepyrn, maybe that would make it a curative. I'm also reading that Grub Ex has to make its way through the soil profile to become effective. I don't know it that is true for armyworms. They are on the surface eating above ground foliage, not roots. Does chlorantraniliprole have to be absorbed into the grass (through foliage? through roots?) to be effective?


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## Easyluck (Feb 5, 2019)

Chlorantraniliprole can be used to control armyworms as a contact insecticide or systemic insecticide. It comes in both a liquid and granular. Either can be used for contact or systemic.

From the study you posted, it would be nice to know if liquid or granular was used. If granular did they lightly irrigate to was the AI off or not?

Scott's GrubEx recommended rate is 2.87 lbs per 1000, which is the equivalent of 0.1 Lb AI/A.

Acelepryn comes in both a liquid and granular.

Acelepryn G (granular) has a recommended rate of 0.1 - 0.2 lb AI/A.

The liquid Aceleprn rate to control armyworms via contact is 0.026-0.052 LB AI/A. You can also use it as a systemic insecticide to prevent armyworms.

Regardless which product you use, when applied at 0.1 - 0.2 LB AI/A and watered in, the entire grass plant will be protected from armyworms and grubs for 4+ months. After watering in the roots will absorb the insecticide and spread to the entire plant. Use the higher rate for longer residual.


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## Virginiagal (Apr 24, 2017)

Thanks, @Easyluck. If chlorantraniliprole can be both a curative and preventative, it would seem to be the best choice for fall armyworms. Bifenthrin is not absorbed by the plant so it's going to wash off and may not be in place (though I guess it's still on the soil) if applied too early, like when the armyworms are in the pupa or moth stage. In my case, I applied bifenthrin two weeks ago and GrubEx (at bag rate) a week ago and moths have been flying up every time I water the grass seed to repair damage. There are still armyworms to come from all those dozens and dozen of moths, which weren't affected by either product. I guess the pupa state protects them from any insecticide.


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## Easyluck (Feb 5, 2019)

Bifenthrin does have a rain fast time and provides good residual at high rates, up to 30 days (amount of sunlight, temperatures, mowing frequency and rain likely impact residuals). So it can act as a contact preventative but you won't get months of protection. For example, you spray today and eggs hatch in a week. Those baby armyworms will probably die from the application a week ago. The cost compared to chlorantraniliprole is much cheaper.


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## Frankzzz (Aug 23, 2021)

Bifen IT or Bifen XTS? Shouldn't XTS have a longer residual than IT, since it's oil based vs IT being water based?


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## Easyluck (Feb 5, 2019)

Bifen XTS is an emulsifiable concentrate (EC). Bifen IT is a suspension concentrate (SC). I think I remember reading ECs are less prone to photodegradation therefore longer residuals.

If spraying bushes for mosquitoes then residuals are impacted by UV light and rain.

But for grass you also have a mowing variable. Grass type, crown height, mowing frequency, height of cut, clippings (bag or not). I think they all play a role in contact insecticide residuals.

One disadvantage of ECs is it can easily absorb in the skin of humans and animals.


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## Cluelessone (Sep 23, 2020)

Any experience with Intrepid 2F?

https://www3.epa.gov/pesticides/chem_search/ppls/062719-00442-20150929.pdf


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## Cluelessone (Sep 23, 2020)

A few more in the table at the bottom of this article. It's all about pastures and hay fields, but any experience with turf?

http://extension.msstate.edu/publications/fall-armyworms-hayfields-and-pastures


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