Australian Journal of Agricultural Research (2000) 51, 361-370

R. Chapman, T.J. Ridsdill-Smith and N.C. Turner (2000)
Water stress and redlegged earth mites affect the early growth of seedlings in a subterranean clover/capeweed pasture community
Australian Journal of Agricultural Research 51 (3), 361-370
Abstract: The impact of water stress and infestations of redlegged earth mite [Halotydeus destructor Tucker (Acarina : Penthaleidae)] on the early growth and botanical composition of a mixed subterranean clover (Trifolium subterraneum L.) and capeweed (Arctotheca calendula Levyns) pasture was investigated in a controlled environment experiment. Water stress and redlegged earth mite infestations both significantly reduced herbage production from both species. The yield of the subterranean clover was suppressed less by water stress than that of the capeweed. The differing sensitivities of the two species to water stress were attributed to differences in seedling size and growth rates at the onset of the drought.
Redlegged earth mites caused greater feeding damage on cotyledons of the subterranean clover than of the capeweed. Despite this, the mites had a greater deleterious impact on the growth of the capeweed, which was suppressed both in the presence and absence of water stress. Redlegged earth mites in the presence of water stress did not significantly affect the growth of the subterranean clover. Furthermore, in the absence of water stress, the growth of the subterranean clover was greater when mites were present than when absent. The greater sensitivity of the capeweed to the effects of feeding by the redlegged earth mites was attributed to the smaller size of its seedlings at the time the redlegged earth mites were introduced. The increase in growth of the subterranean clover following the introduction of redlegged earth mites is more likely due to a change in the competitive relationships between the two plant species than to any direct effect of the mites' feeding.
Our observations indicate that the presence of water stress and redlegged earth mites significantly affects the competitive interactions between seedlings of subterranean clover and capeweed.
(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): Thomas James Ridsdill-Smith

Research topic(s) for pests/diseases/weeds:
damage/losses/economics
environment - cropping system/rotation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Halotydeus destructor	Clover (Trifolium)