|Danehower, David - NORTH CAROLINA STATE UNIV|
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: June 27, 1995
Publication Date: N/A
Interpretive Summary: Many Nicotiana species, including tobacco, have leaf hairs that produce chemicals with a variety of biological activities, including toxic effects on plants, diseases, and insects. Certain compounds from tobacco stimulate egg laying by tobacco budworm and tobacco hornworm moths. Also, volatile components may affect behavior of insect pests and beneficial biological control agents. Some compounds are toxic to the aphids and whiteflies, an they may reduce the growth and development of fungal or bacterial diseases of crops. Because insect pests come in contact with chemicals on the leaf surface, breeding lines with high levels of these components are being developed. The use of these natural insecticides for control of soft-bodied insects is being studied.
Technical Abstract: Many Nicotiana species have glandular trichomes that produce complex chemical exudates, which consist primarily of diterpenes (duvanes and labdanes) and/or sugar esters (sucrose esters and glucose esters). These components have a variety of biological activities, including allelochemical effects on plants, microorganisms, and insects. Duvane diterpenes and sucrose esters from tobacco, N. tabacum, stimulate the ovipositional behavior of lepidopteran pests, Heliothis virescens (F) and Manduca sexta (L). Volatile components produced by Nicotiana species also affect orientation and alighting behavior of insects pests and beneficials. Diterpenes and sugar esters from several Nicotiana species are topically toxic to the tobacco aphid, Myzus nicotianae Blackman, the greenhouse whitefly, Trialeurodes vaporarium (Westwood), and the silverleaf whitefly, Bemisia argentifolii Bellows & Perring. These compounds also reduce growth hdevelopment of fungal and bacterial pathogens of tobacco and other crops. Because pests come in contact with exudates on the leaf surface of Nicotiana species, breeding lines with high levels of these components are being developed. The use of sugar esters as natural insecticides for control of soft bodied insects such as whiteflies and aphids is being pursued.