Management Options and Factors Affecting Control of a Common Waterhemp (Amaranthus rudis) Biotype Resistant to Protoporphyrinogen Oxidase-Inhibiting Herbicides

Table 1

Environmental conditions and plant size for preemergence and postemergence applications for field research in 2002 and 2003.

Application	2002	2003
Preemergence
Date	19 April	2 May
Air temperature (°C)	22	18
Soil temperature (°C)	18	16
Postemergence
Date	6 June	27 June
Height (cm)	5–25	5–20
Leaf number	6–10	4–12
Population (no/m^2)	419–586	382–528
Cloud cover (%)	5	8
Relative humidity (%)	33	57
Air temperature (°C)	30	25