Evaluating pasture legumes for resistance to aphids

Sixteen pasture legume species from 11 genera (Astragalus, Biserrula, Hedysarum, Hymenocarpus, Lotus, Medicago, Ononis, Ornithopus, Scorpiurus, Trifolium and Trigonella) were evaluated for resistance to 3 aphid species (Therioaphis trifolii (Monell) fm. maculata, Acyrthosiphon kondoi Shinji, and Aphis craccivora Koch) at 14, 28 and 42 days after the legumes were sown in a glasshouse. Eleven of the 16 cultivars/accessions were resistant to T. trifolii, 8 were highly resistant to A. kondoi but none of the accessions or cultivars were resistant to A. craccivora at all growth stages. Ononis alopecuroides L. and Ornithopus compressus L. were the most resistant of all plants tested. The amount of resistance to the aphids was significantly affected by the age of the plants, but was less pronounced in the case of A. kondoi.