EVALUATION OF A RANGE OF VARIETIES OF WHITE CLOVER FOR RESISTANCE TO FEEDING BY WEEVILS OF THE GENUS SITONA

Experiments were done to evaluate a range of 18 varieties of white clo ver (Trifolium repens L.); AberHerald, Katrina, Gwenda, Olwen, Alice, AberDale, Menna, S184, Siwan, Donna, Grasslands Huia, Kersey, Milkanov a, AberDai, Nesta, AberEndura, AberVantage and AberCrest for resistanc e to feeding by two common species of clover weevil (Sitona lineatus L . and S. flavescens Marsh.). Art index of feeding preference, relative to feeding on a standard variety (Grasslands Huia) was calculated for the 18 varieties. Of the varieties tested six (Kersey, Gwenda, AberHe rald Olwen, Siwan and Alice) were less favoured by S. flavescens than the standard variety, Grasslands Huia, and only one, AberDai, was sign ificantly (P<0.001) move susceptible to feeding. For S. lineatus only four varieties (AberHerald, Katrina, Gwenda and Olwen) were less favou red and two varieties (AberVantage and AberCrest) were significantly ( P<0.001) more favoured than Grasslands Huia. Kersey, AberDai and AberC rest were all move susceptible to feeding by S. lineatus than by S. fl avescens. In order to determine whether the HCN potential of the clove r had any effect on weevil feeding, five different lines (a, b, c, d, e) of an experimental variety of white clover, Ac52, each line having been bred for different HCN potential, were tested for feeding prefere nce by the weevils. In some cases feeding on the high HCN potential pl ants was significantly (P<0.05) higher than on the plants of low HCN p otential.