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Wednesday, June 22, 2022

Highest Fall Armyworm Numbers in 12 Years of Trapping

The title of the article pretty much says it all; for the week ending today on June 22 I caught 1,242 fall armyworm moths per trap at Lubbock. The prior record, 912, was set in 2021 when FAW caused extensive damage as far as the upper Midwest. 



Thanks to some genetic work done by Ashley Tessnow, a post-doctoral researcher at Texas A&M, we know the vast majority of May moths were "corn strain" fall armyworms. However, she found that our summer flight might be as much as 35% "rice strain" mixed in.  This is not to say the majority of moths from this week won't go to sorghum or pasture grasses, for they surely will - the host preference between strains is not that strong. 

The bottom line is that any of our crops that are susceptible to fall armyworm should be scouted. Our Bt corn will provide good control of these larvae on whorl stage plants. However, sorghum, especially small sorghum, is at significant risk, as are any of the other host crops including vegetables. 

In looking back on my 12 years of data it is apparent that FAW numbers have increased on average over the years. I don't have an explanation for this, but I know what I am seeing. I am using the same pheromone lure year after year, and the traps are in the same place, so I think it is fair to say that increasing fall armyworm is a real phenomenon.