Euphorbia heterophylla (wild poinsettia) is reported as an emerging weed in cotton and processing tomato in Kopaida plain, region of Viotia, in central Greece. This is the first record of E. heterophylla in tomato crop in Greece. In a field experiment, mature plants grown under weed-free conditions produced on average 19 heads, 64 capsules, and 192 seeds per individual plant. Mature seeds exhibited no dormancy and the maximum germination (82 to 90%) occurred at temperatures from 25 to 35°C, with a drastic decline (<38%) at 15 and 40°C. Light had no significant effect on seed germination in the whole range of temperatures tested. Fully mature plants were taller than cotton, exerting strong competition. Having no light dependence for germination, seeds might have the potential to germinate and emerge from greater soil depths. This short communication summarizes information for the identification, seed germination and growth of this weed species that would support a proper weed management
