Steinbauer, M.Taylor, G.Madden, J.2007-05-112007-05-111997Entomologia Experimentalis et Applicata, 1997; 82(2):175-1800013-87031570-7458http://hdl.handle.net/2440/27955Amorbus obscuricornis (Westwood) and Gelonus tasmanicus (Le Guillou) (Heteroptera: Coreidae) are specific to Eucalyptus (Myrtaceae). A obscuricornis feeds almost exclusively upon apical shoots and causes a characteristic wilting and necrosis. By comparison, the feeding activities of G. tasmanicus result in no obvious phytotoxicosis. Salivary gland extracts from both species exhibited sucrase activity but no pectinmethylesterase (PME) activity. Saliva from A obscuricornis also exhibited considerable oxidase activity. Sucrase activity was significantly higher in extracts derived from G. tasmanicus than from A. obscuricornis, but this could not explain the observed differences in phytotoxic symptoms. It is suggested that differences in plant damage are attributable to the site of feeding activity (i.e. young versus mature tissue), which predetermines the reactivity of host tissues, and/or the quantity of salivary enzymes injected.en© 1997 Kluwer Academic PublishersCoreidaeEucalyptusHemipteraphytotoxicosessalivary enzymesJournal article003000253810.1046/j.1570-7458.1997.00128.x66544Taylor, G. [0000-0002-4082-5459]