EPPO Alert List Euphorbia davidii (Euphorbiaceae)

 

 

Why

Euphorbia davidii has been present in the EPPO region for a number of years where it occurs often in small populations along railway lines. However, E. davidii can also invade agricultural habitats and recently the species has been reported in new areas in Central Russia.

 

Geographical distribution

EPPO region: Bulgaria, France, Hungary, Italy, Moldova, Russia, Serbia, Ukraine.

North America: Canada, Mexico, United States: Arizona (native), Arkansas, California (native), Colorado, Connecticut, Delaware, District of Columbia, Florida, Illinois, Indiana, Iowa, Kansas, Kentucky, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Nebraska, New Hampshire, New Jersey, New Mexico (native), New York, North Carolina, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, West Virginia, Wisconsin, Wyoming.

Oceania: Australia.

 

 

Euphorbia davidii – Andrey Zharkikh Wikimedia Commons

Morphology

Stem: erect or ascending, 20–70 cm, both coarsely and sparsely hirsute and closely strigillose; branches usually straight, occasionally proximal branches arcuate.

Leaves: usually opposite, occasionally alternate at distal nodes; petiole 7–25 mm, strigose; blade usually narrowly to broadly elliptic, occasionally lance-elliptic, 10–100 × 5–35 mm, base cuneate to attenuate, margins coarsely crenate-dentate, strigose, revolute to nearly flat, apex broadly acute to acuminate, or obtuse, abaxial surface strigose with stiff, strongly tapered hairs, adaxial surface sparsely strigose-hirsute; venation pinnate, midvein prominent.

Flowers: 5–8. Pistillate flowers: ovary glabrous or sparsely strigose. Capsules broadly ovoid, 3-lobed, glabrous.

Seeds: black to brown or pale grey, ovoid to triangular-ovoid, angular in cross section, 2.4–2.9 × 2.2–2.9 mm.

 

Biology and Ecology

Euphorbia davidii is an annual species that spreads locally by seed. In the EPPO region (Serbia) flowering occurs in August-September and fruiting in September – October.

 

Habitats

Ruderal habitats including transportation networks (rail lines and roadsides), port areas and industrial areas. Agricultural habitats (soybean and maize) and vineyards.

 

Pathways for movement

The potential pathways for entry into the EPPO region are unclear. However, it is suggested in the literature that the species may have entered as a contaminant of seed consignments.

 

Impacts

Euphorbia davidii can form dense stands in agricultural areas. There are observations from Serbia that the presence of dense patches can have a negative effect on the size of maize plants and can initiate early ripening of sunflower heads.

 

Control

Chemical control options include foliar spraying which has been assessed but with limited effectiveness.

 

Sources

Barina Z, Shevera M, Sirbu C, Pinke G (2013) Current distribution and spreading of Euphorbia davidii (E. dentata agg.) in Europe. Central European Journal of Biology 8(1), 87-95.

Purger D, Vajgand D, Mićić N, Vajgand K (2015) Euphorbia davidii Subils (Euphorbiaceae), a new alien species in the flora of Serbia. Botanica Serbica 39, 49-52.

Vajgand DK, Mićić ND, Purger DI (2014) Euphorbia davidii - an invasive weed species in the fields of Serbia. Matica Srpska Journal National Science 127, 57-64.

Vladimirov V, Petrova AS (2009) A new alien species of Euphorbia (Euphorbiaceae) to the Bulgarian flora. Phytologia Balcanica 15, 343-345.

Tokhtar VK, Kurskoy AY (2019) [Euphorbia davidii Subils (Euphorbiaceae) – a new species for Central Chernozem Region (Russia)]. Phytodiversity of Eastern Europe XIII (4), 397–401 (in Russian)