Boll Weevil - Life Cycle

Life Cycle

Adult weevils overwinter in well-drained areas in or near cotton fields after diapause. They emerge and enter cotton fields from early spring through midsummer, with peak emergence in late spring, and feed on immature cotton bolls. The female lays about 200 eggs over a 10–12 day period. The oviposition leaves wounds on the exterior of the flower bud. The eggs hatch in three to five days within the cotton squares (larger buds before flowering), feed for eight to ten days, and finally pupate. The pupal stage lasts another five to seven days. The life cycle from egg to adult spans about three weeks during the summer. Under optimal conditions there may be eight to 10 generations per season. According to the book "From Can See to Can't" by Thad Sitton and Dan Utley, "Under ideal conditions for reproduction – which fortunately seldom existed – the progeny of a single pair of weevils emerging in the spring could reach something like 134 million before the coming of frost.

Boll weevils will begin to die at temperatures at or below −5 °C (23 °F). Research at the University of Missouri indicates they cannot survive more than an hour at −15 °C (5 °F). The insulation offered by leaf litter, crop residues, and snow may enable the beetle to survive when air temperatures drop to these levels.

Other limitations on boll weevil populations include extreme heat and drought. Its natural predators include fire ants, insects, spiders, birds, and a parasitic wasp, Catolaccus grandis. The insects sometimes emerge from diapause before cotton buds are available.