Control of Orobanche crenata in legumes intercropped with fenugreek (Trigonella foenum-graecum)

Grain legume production in the Mediterranean Area is threatened by the holoparasitic plant Orobanche crenata, to which little resistance is available in affected crops. Control strategies have centred around agronomic practices and the use of herbicides, although success has been marginal. Several authors have described fenugreek as a suitable crop for intercropping with legumes, reducing the infection level of O. crenata; however, there is an important lack of experimental data and of a systematic research of the mechanisms involved in the reduction of parasitic infection. Two years of field experiments and further investigation by mini-rhizotron and pot experiments showed a decrease of O. crenata infection due to an allelopathic interference on the parasitic life cycle at the level of germination. Inhibition of O. crenata seed germination by allelochemicals released by fenugreek roots is suggested as the mechanism for reduction of O. crenata infection.