To mow or not to mow
Framers do rather not want toxic plants in their grass clippings that they use as feed for their animals. Now American researchers show in Scientific Reports that mowing actually contributes to the distribution of the toxic silverleaf nightshade (Solanum elaeagnifolium).
When plants are stressed they turn to survival mode. This enables plants to reproduce, even when things go pear shaped. Especially plants that humans earmark as weeds appear to do this especially well. These plants distribute super quickly despite, or maybe due to, human intervention. The researchers therefore decided to study the effect of mowing on the weed silverleaf nightshade.
Earlier published research already showed that the seeds of mowed plants that survived were heavier and germinated better, than those of not mowed plants. Now the researcher studied the flowers.
Mowing of the silverleaf nightshade actually helps its distribution
They noticed that the flowers of plants that survived being mowed were bigger. In addition the researchers noted that these plants had more stems containing flowers. Moreover, the flower petals were less munched on by insects. And the larvae that fed on those petals grew less quickly.
All suggesting that mowed silverleaf nightshade plants scale up their defence response. Because of this, less insects damage the plants, resulting in more mowed plants surviving long enough to develop seeds. Mowing is actually giving weeds like the silverleaf nightshade a double advantage: they survive better, and make healthier seeds that germinate more readily. Explaining how they can distribute quickly.
Although it has to be said that this study does not show that other weeds use the same mechanisms. But when this turns out to be the case, then a better control strategy might be not mowing instead of mowing.
Literature
Chavana, J., Singh, S., Vazquez, A. et al. Local adaptation to continuous mowing makes the noxious weed Solanum elaeagnifolium a superweed candidate by improving fitness and defense traits. Sci Rep 11, 6634 (2021). https://doi.org/10.1038/s41598-021-85789-z
Vasquez, A., Alaniz, A., Dearth, R. et al. Continuous mowing differentially affects floral defenses in the noxious and invasive weed Solanum elaeagnifolium in its native range. Sci Rep 14, 8133 (2024). https://doi.org/10.1038/s41598-024-58672-w
Plant en Zo 