In bagged and unbagged shoot experiments, we investigated the survival and growth rate of first instar larvae of Chrysophtharta bimaculata on 9 families of a natural host, Eucalyptus regnans. Families used had been previously assessed as being either of low or high susceptibility to C. bimaculata damage. In conjunction with larval experiments, we measured 24 tree and leaf characteristics (including foliar elemental concentrations, foliar terpenes, leaf toughness and tree growth rates) and attempted to correlate the plant characters measured with differences in larval performance and previous scorings of E. regnans family susceptibility. First instar larval growth and survival did not differ significantly across families or between low and high susceptibility family groups ( = susceptibility classes), although survival was significantly greater in bagged than unbagged treatments. As predators were in low abundance at the study site, we attribute higher survival rates of larvae in bagged treatments to increased protection from adverse weather conditions. Only one plant character measured, an unidentified foliar phlorglucinol, was significantly negatively correlated with larval survival. Of the 24 plant characters measured, 11 were significantly different between families and 10 were signficantly different between susceptibility classes. Only 4 plant characters were significantly different at both the family and susceptibility class levels; viz. proportion red leaves, tree height at end of season, trunk volume at end of season and relative growth rate based on tree height. Principle Component Analysis using all plant characters measured, or subsets of them, could not separate individual families or susceptibility classes. Our results suggest that herbivore resistance mechanisms in E. regnans do not affect C. bimaculata larvae, but may influence adult feeding and/or oviposition. © 1996 Birkhäuser Verlag.

Item Type:	Refereed Article
Research Division:	Agricultural and Veterinary Sciences
Research Group:	Crop and Pasture Production
Research Field:	Crop and Pasture Protection (Pests, Diseases and Weeds)
Objective Division:	Plant Production and Plant Primary Products
Objective Group:	Other Plant Production and Plant Primary Products
Objective Field:	Plant Production and Plant Primary Products not elsewhere classified
UTAS Author:	Patterson, KC (Ms Kathryn Clare Patterson)
UTAS Author:	Clarke, AR (Dr Clarke)
ID Code:	7285
Year Published:	1996
Web of Science® Times Cited:	10
Deposited By:	Agricultural Science
Deposited On:	1996-08-01
Last Modified:	2011-09-29
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