* Roggero P, Ciuffo M, Dellavalle G, Gotta P, Gallo S, Peters D (1999) Additional ornamental species as hosts of Impatiens necrotic spot tospovirus in Italy. Plant Disease 83(10), p 967.
* Parrella G, Gognalons P, Gebre-Selassie K, Vovlas C, Marchoux G (2003) An update of the host range of tomato spotted wilt virus. Journal of Plant Pathology 85(4), 227-264.
------- Confirmed host.
* Pisani C, Patel PC, Rosskopf EN, Abbasi M, Aime MC (2019) First report of downy mildew caused by Plasmopara halstedii on Ageratum houstonianum in the United States. Plant Disease 103(11), p 2968.