boll weevil
Anthonomus grandis grandis Boheman, 1843


Anthonomus grandis grandis is thought to be native to South America.
Life Cycle
Adults are small (ca. 12 mm) beetles with long slender snouts and spurs on the upper joint of the front legs. Colors vary from dark, brownish-red to brown or near black. Larvae are C-shaped, legless, cream-colored grubs with brown heads. Egg laying starts when squares reach 1/4 inch in diameter (1/3 grown). Each female lays about 200 eggs during a 10 to 12 day period. Usually, only one egg is laid per square. Oviposition wounds produce a small protrusion on the exterior of the flower bud. The bracts of infested squares flare, yellow and the squares drop. Eggs hatch in three to five days. Newly emerged larvae feed within the squares for eight to 10 days, then pupate. The pupal stage lasts five to seven days. The entire life cycle, egg to adult, requires about three weeks during the summer. There may be eight to 10 generations per season.
Anthonomus grandis grandis migrated into Mexico and the United States. It infested all cotton growing regions and eradication programs were begun in 1978.
Control Efforts
Boll weevils are now considered "eradicated" in most of Georgia. Traditional boll weevil controls included diapause control (sprays and stalk destruction immediately after harvest to prevent weevils from entering diapause), insecticide application at pin-head square stage (to reduce populations of overwintered weevils prior to oviposition), and four to five mid and late season insecticide applications at 3 to 5 day intervals, beginning as early as first bloom.


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Invasive Listing Sources

Taxonomic Rank

Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Atelocerata
Class: Hexapoda (including Insecta)
Infraclass: Neoptera
Subclass: Pterygota
Order: Coleoptera
Suborder: Polyphaga
Infraorder: Cucujiformia
Superfamily: Curculionoidea
Family: Curculionidae
Subfamily: Curculioninae
Tribe: Anthonomini
Genus: Anthonomus
Subject: Anthonomus grandis grandis Boheman, 1843