Moisture and temperature requirements for London rocket (Sisymbrium irio) emergence

London rocket is hypothesized to be the most important overwintering host of the beet leafhopper in southern New Mexico. Knowledge of the environmental factors affecting the emergence of this plant is essential to developing a predictive model for London rocket and leafhopper populations. The temperature and moisture optima for London rocket germination and emergence were assessed using growth chamber studies. Temperatures of 5 to 35 C and soil water tension treatments of -0.01 to -1.5 MPa were tested. Optimal seed burial depth also was assessed. Optimal London rocket germination occurred at approximately 15 C and maximum emergence was achieved at 15 to 20 C with soil moisture tensions of -0.01 to -1.2 MPa. London rocket emergence occurred best at a seed burial depth of 2 mm.