Dt. Patterson, TEMPERATURE AND PHOTOPERIOD EFFECTS ON ONIONWEED (ASPHODELUS-FISTULOSUS) AND ITS POTENTIAL RANGE IN THE UNITED-STATES, Weed technology, 10(4), 1996, pp. 684-688
Environmental factors that affect the growth and development of onionw
eed were evaluated in order to predict its potential range and impact
in the U.S. In controlled-environment experiments, onionweed achieved
60 to 100% of its maximum vegetative growth at temperatures ranging fr
om 18/11 to 30/23 C day/night. The greatest biomass was produced at da
y temperatures of 18 or 24 C and night temperatures of 11 or 17 C. Lea
f production and reproductive development were greatest at 18/11 C. Pl
ants eventually flowered also at 18/17, 24/17, and 24/11 C but not in
any regime with a 30 C-day or a 23 C-night. Flowering occurred earlier
in 16-h photoperiods than in 16-h photoperiods than in g-h photoperio
ds. Climatic analyses revealed no U.S. analogs of the principal Austra
lian onionweed sites. Based on its environmental responses and its pat
tern of distribution as a weed in Australia, onionweed will likely rem
ain confined to the southwestern U.S.