Quinoclamine has been evaluated for POST control of liverwort in nursery crop production. Nearly all previous research has assumed that high spray volumes (e.g., > 935 L/ha) were required for quinoclamine to be effective. To test this assumption, quinoclamine was applied to liverwort in a factorial treatment arrangement of three rates (1.4, 1.9, and 3.8 kg ai/ha), three spray volumes (374, 1,112, and 1,871 L/ha), and two spray pressures (276 and 414 kPa). Control was influenced primarily by quinoclamine rate, although there was a trend for greater control with higher spray pressure. Absorption and translocation studies using ¹⁴C-quinoclamine established that ¹⁴C absorption into liverwort thalli approached 70% of the amount applied within 9 h after application. Although liverwort lacks vascular tissue, ¹⁴C is readily translocated away from the site of entry and tended to accumulate at thallus margins. Neither absorption nor translocation was influenced by spray volume. The perceived requirement for high spray volume may be a misdirected assumption on the basis of the high proportion of inert ingredients within the current formulation. Conversely, this assumption has no basis within liverwort biology or quinoclamine behavior.

Nomenclature: Liverwort, Marchantia polymorpha L; quinoclamine.