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Fall Armyworms

Alabama is currently experiencing a widespread outbreak of fall armyworms with an exceptionally high numbers of caterpillars. It is expected that this forage pest will continue to hang around until the first frost. While fall armyworms can defoliate a field quickly, they rarely kill healthy stands of grass.

Alabama Extension professionals are still getting a lot of questions about what products can control fall armyworms in pastures, especially given the lack of availability in some areas. The following information summarizes the products that Alabama producers can apply and details how the products work, their residual levels, and any grazing/harvest restrictions.

 

Table 1. Insecticides for Pasture Control of Fall Armyworms

* Residual level: low = 1 week or less; medium = 1 to 3 weeks; high = 3 to 4 weeks

Always use pesticides according to label directions.

Trade names are used only to give specific information. The Alabama Cooperative Extension System does not endorse or guarantee any product and does not recommend one product instead of another that might be similar.
Active IngredientProduct ExampleHow it WorksResidual Level*Grazing and Harvest IntervalsNotes
Beta-cyfluthrinBaythroid XLContact or ingestion of treated material; starves to deathLowGrazing: 0 days

Harvest: 0 days
Good coverage is necessary; rapid knockdown
CyfluthrinTombstoneContact or ingestion of treated material; starves to deathLowGrazing: 0 days

Harvest: 0 days
Good coverage is necessary; rapid knockdown
Gamma-cyhalothrinDeclareContact or ingestion of treated material; starves to deathLowGrazing: 0 days

Harvest: 7 days
Good coverage is necessary; rapid knockdown
Zeta-cypermethrinMustang MaxxContact or ingestion of treated material; starves to deathLowGrazing: 0 days

Harvest: 0 days
Good coverage is necessary; rapid knockdown
DiflubenzuronDimilin 2LIngestion of treated material; dies after unsuccessful moltMedium Grazing: not specified

Harvest: 1 day
Only works on small, less than 1-inch worms; may take a few days to see results
MethoxyfenozideIntrepid 2FIngestion of treated material; dies after unsuccessful moltMedium Grazing: 0 days

Harvest: 0 days
Only works on small, less than 1-inch worms; may take a few days to see results
SpinosadBlackhawkContact or ingestion of treated material; starves to deathLowGrazing: 0 days

Harvest: 3 days
Good coverage is necessary; rapid knockdown
MethomylLannate LV2.4Contact or ingestion of treated material; dies from respiratory failureLowGrazing: 7 days

Harvest: 3 days
Good coverage is necessary; rapid knockdown
CarbarylSevin XLR PlusContact or ingestion of treated material; dies from respiratory failureMediumGrazing: 14 days

Harvest: 14 days
Good coverage is necessary; rapid knockdown
ChlorantraniliprolePrevathonIngestion of treated material; stops feedingHighGrazing: 0 days

Harvest: 0 days
Feeding stops right away; death takes 24 to 72 hours
Lamba-cyhalothrin + ChlorantraniliproleBeseigeContact + ingestion of treated material; starves to deathHighGrazing: 0 days

Harvest: 7 days
Rapid knockdown plus long residual

 

For more information about fall armyworm control, contact the Alabama Extension animal sciences and forages regional agent that serves your area.

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