Natural Selections: Anthonomus grandis

The boll weevil immigrated to the U.S. from Mexico in 1892, arrived in Mobile County in 1910, and infiltrated the rest of the state by 1916. During each year of the 80 that followed, the cotton-guzzling beetle cost Alabama between $20 and $40 million in agricultural losses. Thankfully, the costly pest has since been eradicated in the state. Read on for more on the weevil and its unlikely — yet entirely possible — return.

PORT OF ENTRY Since they traveled from Mexico throughout the U.S. via the Gulf Coast, weevils entered Alabama in Mobile. Thanks also to our warm climate and mild winters, the Port City had the heaviest infestation of the cold-intolerant critters compared to the rest of the state.

GOOD RIDDANCE Alabama’s weevil eradication is credited to integrated pest management, a method utilizing field monitoring, treatment thresholds and other cultural controls. Weevil-resistant genetically altered varieties of cotton also helped.

DID YOU KNOW? The 6 millimeter-long beetles are characterized by their elongated snouts, which measure half the length of their bodies. At the end of these conspicuous snouts are the boll weevil’s chewing mouthparts.

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THE BRIGHT SIDE Some praise the weevil for its unexpected positive effects, such as more diverse crops, improvements in the study of insects and advancements in insect control.

MONUMENTAL SUCCESS In 1919, the citizens of Enterprise, Alabama, were so grateful for these positive effects that they erected the only known memorial for an insect in the weevils’ honor, where it still stands today.

FINAL DESTINATION Alabama’s last boll weevil was found in Mobile County in 2003. “Someone professionally monitoring cotton fields in Mobile happened to be commuting out of Mississippi where the weevil was still present at that time, ” Dr. Ronald Smith (see right), says. “It’s likely they brought it in.”

DID YOU KNOW? Weevils feed on the fibers of immature cotton buds known as “bolls.” Mothers lay their eggs inside these bolls, and the resulting larvae consume the fibers inside, usually until the now-useless pod falls off.

That Evil Weevil

Born into a long line of small cotton farmers, professor emeritus Dr. Ronald Smith has been Auburn University’s cotton-based entomologist for 43 years and counting. 

  • “There’s really no way to put a number on the billions of dollars that boll weevils cost farmers over the approximately 85 years they were in Alabama, ” Smith says. “It was one of the most significant events in Alabama agricultural history when they were eradicated.”
  • “As the eradication program progressed, ” Smith says, “Weevils were brought back in from areas west of us.” They did this by hitchhiking on farm equipment or on workers coming from Mexico and Texas.
  • In the U.S. today, “the weevil has been eliminated everywhere except the Rio Grande Valley in Texas.” This is due to the area’s mild climate and the impossibility of flying pesticide planes in the dangerous, drug-addled region. But Smith is confident that weevils can be contained there. “We would be able to detect a problem before it got out of hand.”
  • Bottom line? “We’ll never be able to totally let our guard down as long as there are weevils in south Texas, ” Smith says. “It’s not impossible for them to come back. We have been more than a decade now without finding one, though, so that’s really good news.”

text by HALEY POTTS • illustration by kelan mercer

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