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ARS Home » Southeast Area » Stoneville, Mississippi » Southern Insect Management Research » Research » Publications at this Location » Publication #266958
Title: Fall armyworm (Lepidoptera: Noctuidae) development survivorship and damage on cotton plants expressing insecticidal plant-incorporated protectants

Author
item HARDKE, J - Louisiana State University
item Jackson, Ryan
item LEONARD, B - Louisiana State University
item TEMPLE, J - Louisiana State University

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/18/2011
Publication Date: 6/9/2015
Citation: Hardke, J.T., Jackson, R.E., Leonard, B.R., Temple, J.H. 2015. Fall armyworm (Lepidoptera: Noctuidae) development survivorship and damage on cotton plants expressing insecticidal plant-incorporated protectants. Journal of Economic Entomology. 108(3):1086-1093;DOI:10.1093/jee/tov092.

Interpretive Summary: Bt cotton that produced a single protein that was toxic to heliothines was introduced in 1996. Tobacco budworm was the primary target of this technology, but it also provided suppression of bollworm. In 2002, cotton that produced two Bt proteins (Bollgard II® and WideStrike™) was commercialized, and this technology targeted bollworm and secondary caterpillar pests, such as fall armyworm, beet armyworm, etc. Because this technology has not demonstrated a “high dose” for bollworm and the armyworm complex, information that quantified fall armyworm survivorship and subsequent feeding damage on the different Bt cotton technologies was needed. Single-gene Bt cotton (Bollgard®) had no impact on fall armyworm survival and damage. Bollgard II cotton was inconsistent in its activity against fall armyworm as measured against the non-Bt control line. However, WideStrike cotton was the most consistent technology with regard to reducing fall armyworm survivorship and subsequent fruit damage compared to the non-Bt variety. These data indicate that differences exist between Bt technologies relative to their activity against an occasional pest, fall armyworm. Producers within areas that are frequently infested with fall armyworm populations should consider the Bt technology within the varieties that are selected.

Technical Abstract: Cotton, Gossypium hirsutum (L.), plants expressing insecticidal crystal (Cry) proteins of Bacillus thuringiensis (Bt) Berliner are planted on significant acreage across the Southern region of the United States. Fall armyworm, Spodoptera frugiperda (J. E. Smith), can be a significant cotton pest in some years, but this species has not been a primary target of Bt cotton technologies. The objective of this study was to quantify fall armyworm larval survivorship and fruiting form injury on transgenic cotton lines expressing Cry1Ac (Bollgard®), Cry1Ac + Cry2Ab (Bollgard II®), and Cry1Ac + Cry1F (WideStrike™) Bt proteins. Larval survivorship and fruiting form damage of fall armyworm on Bollgard, Bollgard II, WideStrike, and non-Bt (control) cotton lines were evaluated in no-choice field studies. Fall armyworm (third instars) were placed on flower buds (squares), white flowers, and bolls, enclosed within a nylon mesh exclusion cage, and evaluated at selected intervals after infestation. Exposure of fall armyworm larvae to Bollgard cotton lines generally resulted in no significant effects on survivorship compared to larvae exposed to the non-Bt cotton line. Survivorship and plant injury by fall armyworm on Bollgard II cotton lines was variable and significant differences compared to non-Bt cotton lines did not occur consistently. Fall armyworm had significantly lower survivorship and caused less plant injury on WideStrike cotton lines than on non-Bt cotton lines across all structures. Development and survivorship of fall armyworm larvae on these cotton lines also were evaluated in no-choice laboratory assays by offering the previously described fruiting forms to third instars. Bollgard II and WideStrike cotton lines significantly reduced fall armyworm development and survivorship compared to those larvae offered non-Bt tissue. These results suggest that differences exist between currently available Bt cotton technologies in their performance against fall armyworm.