INTERVALS BETWEEN BOLL WEEVIL (COLEOPTERA: CURCULIONIDAE) OVIPOSITION AND SQUARE ABSCISSION, AND DEVELOPMENT TO ADULTHOOD IN LOWER RIO GRANDE VALLEY, TEXAS, FIELD CONDITIONS

Authors: Showler, Allan; CANTU, RAUL

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2005
Publication Date: 5/1/2005
Citation: Showler, A., Cantu, R.V. 2005. Intervals between boll weevil (Coleoptera: Curculionidae) oviposition and square abscission, and development to adulthood in Lower Rio Grande Valley, Texas, field conditions. Southwestern Entomologist. 30(3):161-164.

Interpretive Summary: The boll weevil is an important cotton pest that lays eggs in cotton fruit, which drops from the plant. Adult weevils later emerge from the fallen fruit. Information is available on the interval between egg lay, fruit drop, and weevil emergence for temperate regions, but not for subtropical environments. The interval between egg lay and fruit drop was 3.3 days shorter and the interval to weevil emergence 1.2 days longer in the Lower Rio Grande Valley of Texas than in temperate regions. These results indicate that weevils are protected from insecticide applications during the cotton growing season for different intervals in subtropical regions than in temperate regions, and knowledge of the intervals will lead to more timely and effective insecticide treatments.

Technical Abstract: Information on intervals between boll weevil egg laying in cotton squares and when the square falls to the ground, and when the adult weevil emerges from the fallen square, have not been reported on since 1912, and that data was obtained from temperate regions, not the subtropical conditions of the Lower Rio Grande Valley of Texas. This study reports that 6.2 and 5.3 d in 2002 and 2003, respectively, elapsed between boll weevil, Anthonomus grandis grandis Boheman, oviposition and square abscission under field conditions in the Lower Rio Grande Valley of Texas. Oviposition to adult weevil emergence from the square took an average of 18.5 d in 2002 and 16.2 d in 2003. Although significant minimum and maximum daily ambient temperature differences were detected between the separate sampling periods in May and June of 2002, oviposition to square abscission and adult emergence periods were not significantly affected.