SEASONAL PINK BOLLWORM, PECTINOPHORA GOSSYPIELLA (SAUNDERS), INFESTATIONS OF TRANSGENIC AND NON-TRANSGENIC COTTONS

Authors: HENNEBERRY, THOMAS; JECH, LYNN

Submitted to: Southwest Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary: The pink bollworm (PBW), has been a key pest in cotton production systems in the southwest for 35 years. Control costs alone have exceeded 1.2 billion dollars. Transgenic cotton (Bt) carrying the gene that controls production of an insect toxic crystalline protein has been a major technology breakthrough for lepidopterous insect control. We artificially infested Bt cotton with PBW eggs from moths of a laboratory colony or exposed Bt cotton to PBW populations in the field. For artificial egg infestations, larval survival percentages were 21.5 for DPL 5415 (non-Bt control) and < 0.1 for Bt cotton. Seven surviving PBWs were found in Bt bolls during the season. All F1 progeny obtained from the survivors died on Bt bolls, but 50% boll infestation with 0.6 larvae per boll occurred following larval release on DPL 5415 bolls. This indicates no developed tolerance to the Bt cotton or surviving larvae were from non-Bt seed that contaminated Bt seed lots. In the field, immature Bt cotton bolls developing on plants 180 days after planting (DAP) were as toxic to PBW larvae as immature bolls developing on plants 83 DAP. Random boll sampling in plots showed an average of 31 and < 1% boll infestations in DPL 5415 and Bt cottons, respectively. The study showed that the Bt toxic protein technology continues to be outstanding for season-long PBW control. There were no indications of reduced efficacy in late-season bolls.

Technical Abstract: The pink bollworm (PBW), has been a key pest in cotton production systems in the southwest for 35 years. Control costs alone have exceeded 1.2 billion dollars. Transgenic cotton (Bt) carrying the gene that controls production of an insect toxic crystalline protein has been a major technology breakthrough for lepidopterous insect control. We artificially infested Bt cotton with PBW eggs from moths of a laboratory colony or exposed Bt cotton to PBW populations in the field. For artificial egg infestations, larval survival percentages were 21.5 for DPL 5415 (non-Bt control) and < 0.1 for Bt cotton. Seven surviving PBWs were found in Bt bolls during the season. All F1 progeny obtained from the survivors died on Bt bolls, but 50% boll infestation with 0.6 larvae per boll occurred following larval release on DPL 5415 bolls. This indicates no developed tolerance to the Bt cotton or surviving larvae were from non-Bt seed that contaminated Bt seed lots. In the field, immature Bt cotton bolls developing on plants 180 days after planting (DAP) were as toxic to PBW larvae as immature bolls developing on plants 83 DAP. Random boll sampling in plots showed an average of 31 and < 1% boll infestations in DPL 5415 and Bt cottons, respectively. The study showed that the Bt toxic protein technology continues to be outstanding for season-long PBW control. There were no indications of reduced efficacy in late-season bolls.