Main conclusions 

Solanum carolinense presents a high phytosanitary risk for the endangered area with moderate uncertainty.

The likelihood of further entry into the EPPO region occurring via grain of soybean (Glycine max), maize (Zea mays), and wheat (Triticum spp.) for animal feed is high with a low uncertainty. For seeds of Glycine max and Zea mays the likelihood of new introductions is moderate with high uncertainty. Entry into the EPPO region via hay is low with a moderate uncertainty. 

Within the EPPO region, the species predominately grows in managed habitats such as ruderal and agricultural habitats. S. carolinense can invade many spring crops in particular late sowing crops like maize, oil-pumpkin and soybean. In agricultural habitats, it is unlikely that competition with cultivated plants and current management practices would prevent the establishment of the species. 

The likelihood of establishment outdoors is very high with low uncertainty. However, in protected conditions, it is low with moderate uncertainty. The potential for spread within the EPPO region is high with a moderate uncertainty. S. carolinense can spread both naturally and via human assisted spread. Seed or root fragments of S. carolinense can be spread with the movement of agricultural machinery and plant products (e.g. grains, seeds and hay) within the EPPO region. 

The magnitude of impact in the current area of distribution (North America and Japan) is high – there are known impacts on agriculture and in pastures in the USA, and once it is established the species is highly difficult to eradicate and therefore continued management is required. In Japan, there are known impacts in landscape areas which incur costs to control. The EWG considered that the potential socio-economic impacts in the EPPO region will be high with a moderate uncertainty.