Control of Ditylenchus dipsaci by mechanical selection of lucerne seeds
In 1993-1994, heavy infestations of Ditylenchus dipsaci (EPPO A2 quarantine pest) were observed on lucerne in Emilia-Romagna (Italy). Studies were carried out on the efficacy of mechanical selection of lucerne seeds to control D. dipsaci. Mechanical methods (aspiration, ventilation, sieving etc.) can eliminate seeds of other plant species, plant debris and altered (shrivelled, empty etc.) seeds of lucerne which are likely to carry the nematode. The results showed that D. dipsaci was present at a very low level (0.07-0.08 %) in mechanically selected seeds, and at high levels in weed seeds and plant residues with which lucerne seeds are naturally mixed (97 %) and also in the dry stems of lucerne plants (95 %). In addition, field observations confirm that D. dipsaci occurs in mechanically selected dry seeds at low population densities (1-2 nematode/10 g), while in non-selected seeds, nematode populations can be as high as 84 nematodes per 10 g. The authors concluded that the use of selected lucerne seeds (without seeds of other species and plant debris) is a good control method, whereas the control of the nematode in the field is not efficient as it is very difficult to distinguish healthy plants from contaminated plants.
Sources
Tacconi, R.; Pola, R.; Santi, R.; De Vincentis, F. (1995) [Effect of mechanical selection on natural alfalfa seed infested by Ditylenchus dipsaci.]
Nematologia mediterranea suppl., 23, 129-133.
Tacconi, R.; Santi, R.; Pola, R.; De Vincentis, F. (1996) [Field observation on the occurrence Ditylenchus dipsaci on alfalfa in reproduction.]
Nematologia mediterranea, 24, 245-248.