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United States Department of Agriculture

Agricultural Research Service

Title: Survival and Development of Tobacco Hornworm Larvae on Tobacco Plants Grown under Elevated Levels of Ozone and Ultraviolet-B Radiation

Authors
item Jackson, David
item Rufty, T - NC STATE UNIVERSITY
item Heagle, Allen
item Severson, R. - DECEASED
item Eckel, R - RVWE CONSULTING

Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 16, 1999
Publication Date: N/A

Interpretive Summary: Tobacco plants were grown under a range of ozone concentrations and ultraviolet-B radiation levels in open-top chambers at the USDA-ARS, Air Quality Research Unit at North Carolina State University, Raleigh. Ozone concentrations were established by charcoal filtration, which reduced ozone to approximately half ambient, or by addition of ozone to nonfiltered air. Survival of tobacco hornworm larvae, a major pest of tobacco, was increased when they were fed tobacco leaves grown under elevated levels of ozone. Hornworm larvae also gained significantly more weight when they were fed on plants exposed to elevated levels of ozone. Ozone-treated tobacco plants had higher levels of total nitrogen and soluble carbohydrates, and lower levels of leaf-surface components, starch, nicotine, and rutin. Survival and weight gain of hornworm larvae were not affected by ultraviolet radiation. Increased survival and growth response of hornworm larvae to elevated ozone levels in these experiments suggest that similar responses may occur in areas where ozone levels are high enough to injure tobacco plants.

Technical Abstract: Tobacco plants, Nicotiana tabacum L., were grown under a range of ozone concentrations and ultraviolet-B radiation (UV-B) levels in open-top chambers at the USDA-ARS, Air Quality Research Unit, North Carolina State University, Raleigh. Ozone concentrations were established by charcoal filtration (CF), which reduced ozone to approximately one-half ambient, or by addition of ozone to nonfiltered air (NF) to increase concentrations to approximately 1.4 (NF1) or 1.7 (NF2) times ambient. Survival of tobacco hornworm, Manduca sexta L., larvae was increased when second instars were fed tobacco leaves grown under elevated levels of ozone. Second instars also gained significantly more weight when they were fed for one week on plants exposed to elevated levels of ozone than when they were fed plants grown in CF air. Ozone-treated tobacco plants had higher levels of total nitrogen and soluble carbohydrates, and lower levels of leaf-surface components, starch, nicotine, and rutin. Survival and weight gain of hornworm larvae were not affected by UV-B. Elevated UV-B also had little effect on tobacco growth, cuticular chemistry, or internal chemistry. Increased survival and growth response of hornworm larvae to elevated ozone levels in these experiments suggest that similar responses may occur in areas where ozone levels are high enough to injure tobacco plants.

Last Modified: 8/27/2014
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