Biology and control of Heterotheca subaxillaris in Israel
Heterotheca subaxillaris (Asteraecae) or camphor weed is a dicotyledonous winter annual weed native to North America. The plant invaded Israel during the last 20 years and rapidly infested a wide range of habitats including cultivated and non-cultivated ecosystems, such as orchards, nature reserves, range land, open fields, waste grounds, roadsides and railroad embankments.
Experiments highlighted that optimum germination occurs at 28/22°C (day/night), but high germination rate were still recorded even at 34/28°C. Highest emergence (88%) was recorded when seeds were sown at a shallow depth (0-1 cm) in sandy soil. Less than half of the seeds emerged from the shallow depth (0-1cm) in the heavy (clay) soil while no seedlings emerged from deeper layers. H. subaxillaris is very sensitive to herbicides commonly applied in road sides and non-cultivated areas such as atrazine, diuron, sulfometuron and imazapyr at their appropriate recommended rates.
Sources
Quaye M, Yaacoby T, Rubin B (2011) Biology and control of Heterotheca subaxillaris (Camphor weed) in Israel. In Brunel S, Uludag A, Fernandez-Galiano E, Brundu G (Eds.) Proceedings of the 2nd International Workshop on Invasive Plants in the Mediterranean Type Regions of the World, 2010-08-02/06, Trabzon, Turkey pp. 274-282. http://archives.eppo.org/MEETINGS/2010_conferences/ias_trabzon/Proceedings_Trabzon_Workshop.pdf