Redlegged earth mite performance on resistant subterranean clover varieties [Trifolium subterraneum]. [Workshop paper]
1995
Ridsdill-Smith, T.J. | Gaull, K.R. (Commonwealth Scientific and Industrial Research Organisation, Wembley (Australia). Div. of Entomology) | Jiang, Y. | Gillespie, D.J. (Western Australia Univ., Nedlands. CLIMA)
Redlegged earth mite responses and damage to seedlings of resistant and susceptible subclover varieties were measured in the laboratory and in small plots in the field. Mites produced less progeny on resistant varieties, but their survival was not affected. The basis of resistance was antixenosis, which adversely affects mite feeding. Resistance factors were present in or on epidermal or subepidermal cells of cotyledons. Mites alter their normal pattern of foraging after probing the surface of resistant cotyledons. Bioassays have been developed to test extractable chemicals for their role in resistance. No mechanisms have been found involving extractable chemicals, but a mechanisms has been identified which is correlated with leaf hardness. A rearing system has been developed which provides mites for experiments during the summer. Although the reproduction of mites feeding on the older trifoliate leaves was reduced in the laboratory on some varieties tested as seedlings, no corresponding reduction of mite populations during winter was observed in field plots.
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