Biocontrol Science and Technology (1996) 6, 521-530

Fang-Hao Wan, Peter Harris, Lei-Ming Cai and Mao-Xin Zhang (1996)
Host specificity of Altica carduorum Guer. Chrysomelidae: Coleoptera , a defoliator of Cirsium arvense L. Scop. Asteraceae from north-western China
Biocontrol Science and Technology 6 (4), 521-530
Abstract: Traditionally, insects are not approved for release in North America as agents for the biological control of weeds if the larvae complete development on desirable plants in no-choice tests. This criterion excludes the use of the leaf-feeding beetle Altica carduroum Guer. since it can complete development on all Cirsium spp., including rare North American species, although in nature it is only known from the target weed Cirsium arvense. Host suitability is the result of a sequence of selection factors, and this study shows that most discrimination between thistle species is the result of host finding and egg production, and not larval developmental ability. In no-choice tests, the larvae completed development on 18 Cirsium species in five sections of the genus that were tested and on Silybum marianum, but not on other genera in the tribe Cardueae or more distantly related Asteraceae. The adult food consumption on C. arvense was two to eight times greater than on other Cirsium species, many of which, such as C. pitcheri and C. drummondii, received no feeding by over 50 of the beetles in the first 24 h. The best North American thistle for egg production was C. scariosum, but this was only 28 of that on C. arvense. The preference for C. arvense in multiple-choice tests increased with the size 2 of the arena. In the largest, an area of 6 m , 80 of the beetles and eggs were found on C. arvense and none were found on plants outside the subtribe Carduineae. Thus, as theory predicts, host discrimination between thistle species takes place at earlier stages than suitability for larval development, and this should be considered when determining the safety of candidate agents.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Fang Hao Wan

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
non-target effects/fate in environm.
environment/habitat manipulation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Cirsium arvense (weed)		Canada (west)
Altica carduorum (weed bioagent)	Cirsium arvense (weed)