Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Abstract Only
Publication Acceptance Date: January 5, 1997
Publication Date: N/A
Technical Abstract: The bollworm (CBW), Helicoverpa zea Boddie, appears not to damage cotton as much as tobacco budworm (TBW), Heliothis virescens Fab. We infested single row plots of 23 cultivars of cotton, Gossypium hirsutum L. in 1996. We put 6-8 first instar larvae of TBW per row foot in cotton plant terminals each week for four weeks beginning at pre-bloom stage on one half of each cultivar row and on the other half 6-8 first instar larvae of CBW. TBW caused significantly more damage. Seed cotton yield averaged over the 23 cultivars was 1207 lbs. per acre when infestsed by CBW and 812 pounds per acre when infested with TBW. Similiar damage differences were observed in the early part of 1995; however, a high natural infestation of TBW and a late season infestation of beet armyworm, Spodoptera exigua (Hubner) confounded the yield data in 1995. Preliminary data on behavior indicate that bollworm tends to web off cotton terminals more readily than tobacco budworm when each was applied to plant terminals in water picks in the laboratory. In the field, TBW tended to begin feeding immediately; whereas, CBW tended to immediately disperse throughout the plant by crawling and webbing.