Skip to main content
ARS Home » Research » Publications at this Location » Publication #207713
Title: Orientation behavior, development and survival of Trichoplusia ni (Lepidoptera: Noctuidae) larvae on cotton expressing Cry1Ac and Cry2Ab and conventional cotton.

Author
item LI, Y.-X. - TAES,TEXAS A&M UNIVERSITY
item Greenberg, Shoil
item LIU, T.-X - TAES,TEXAS A&M UNIVERSITY

Submitted to: Journal of Insect Behavior
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/31/2007
Publication Date: 9/20/2007
Citation: Li, Y., Greenberg, S.M., Liu, T. 2007. Orientation behavior, development and survival of Trichoplusia ni (Lepidoptera: Noctuidae) larvae on cotton expressing Cry1Ac and Cry2Ab and conventional cotton. Journal of Insect Behavior. 20(5):473-488.

Interpretive Summary: Cabbage looper, Trichoplusia ni, as a secondary cotton pest, may likely become a major pest because the cotton boll weevil eradication program is currently in action, and natural enemies in cotton are under high adverse pressure from multiple applications of insecticides to control the boll weevil. Growers are aware, that in this case, the risk of secondary pest outbreaks will be increased and Bt cotton has proven to be a useful tool for controlling caterpillar pests, and augment activity of beneficial insects. Bt cotton, especially under the boll weevil eradication program, provides management options that have positive environmental, social, and economic outcomes. Understanding the effects of Bt and non Bt cotton on orientation behavior, development, and survival of cabbage looper is certainly essential for developing appropriate strategies to prevent resistance.

Technical Abstract: This study was conducted to determine the effects of Bt cotton (Bollgard II) or a mixture of Bt+non-Bt cotton leaves on larval orientation behavior, survival and development of Trichoplusia ni in the laboratory. Results indicate that in a no-choice test, more first and fifth instars remained on Bt leaves than the third instars. All larvae that remained on the leaves gradually moved to leaf edge. In the choice between a Bt and non-Bt leaf, more first instars moved to non-Bt leaves, whereas the third and fifth instars did not show significant difference in the first 8 h, but eventually more moved to non-Bt leaves. More first instars fed non-Bt leaves than third instars and fifth instars. When larvae fed Bt leaves, 100% of first instars, 92.7% of third instars and 51.1% of fifth instars died in 108 h. Once larvae pupated, >90% developed to adults. First and third instars that fed Bt leaves developed slower but their pupae developed faster than those on Bt+non-Bt leaves, whereas fifth instars developed similar on the three types of leaves. First and third instars that fed Bt+non-Bt leaves resulted in lighter pupae than those fed non-Bt leaves; whereas the fifth instars that survived on Bt leaves produced lighter pupae.