Concern regarding the increasing pest status of the boll weevil, Anthonomus grandis Boheman, in southwestern Arizona cotton, Gossypium spp., growing areas prompted studies during 1981 and 1982 to examine boll weevil seasonal infestations in planted cotton, occurrence and development in late-season bolls, emergence in the winter and early-spring from dry bolls, diapause and initiation of spring infestations.

Peak boll weevil square infestations (22%) occurred in the planted cotton fields near infested stub cotton fields during early-July, 1981. High numbers of boll weevils were found in late-season bolls throughout the planted cotton fields from late-October through December, 1981. At least 2 generations of boll weevils developed in the late-season bolls and approximately 90% of the insects matured to adults by February 1, 1982.

Boll weevil adults emerged from dry bolls elevated 15 cm above the soil and placed on the soil surface until May 23, 1982. No boll weevils emerged from bolls buried in the soil 15 cm deep.

Reproductive boll weevil adults were found from October, 1981 to April, 1982. Approximately 56% of the female and 37% of the male boll weevil adults examined in late-February exhibited at least intermediate diapause.

Boll weevil infestations were found in the initial squares of both an abandoned, regrowing cotton field on May 10 and a planted cotton field on June 2, 1982.