Salinity modulates crop plants suitability as hosts for Cuscuta campestris parasitism

Cuscuta campestris Yunck. is a stem holoparasitic flowering plant, wide-spread and currently considered invasive worldwide. It has both ecological and agricultural significance. However, little is known on how the conditions of the environment, and abiotic stresses in particular, could affect the success of this parasite. A total of 22 potential host plants, belonging to 10 species and 4 families, were tested as C. campestris hosts under different saline regimes. The changes in survival rate (number of successful infections) and growth (as cm day−1) of the parasite were studied. Salinity did significantly change the survival and growth rate of C. campestris, which effect was species- and cultivar-dependent. While generally the survival of the parasite decreased with increasing salinization, the opposite effect was observed on several host plants. However, survival rate did not always coincide with higher growth rate. This suggests that salinity produces different effects on the parasite depending on the host plant and these depend strongly not only on the species, but also on the cultivar. These results strongly suggest that under salt stress the suitability of various crop plants as hosts for C. campestris may change significantly, thus affecting the overall success of the parasite. In the light of the increased salinization of soils, this may have a significant effect on the spread of C. campestris and its agricultural impact.