Experiment 3

METHODS

Herbicides were applied on July 22, 2003 to major liverwort infestations that covered 60% of the container surface. These liverwort had many sporocarps present at the time of application. The following herbicides were applied:

Herbicide Rate
Quinoclamine (Mogeton) 1 oz./gal
Quinoclamine (Mogeton) 2 oz./gal
Quinoclamine (Mogeton) 4 oz./gal
Broadstar 150 lb/acre
TerraCyte 650 lb/acre
Non-treated control  

Irrigation was withheld for 24 hours after herbicide application.


RESULTS

By 2 DAT, Quinoclamine provided 89 to 96% liverwort control, with control increasing with increasing rate. Terracyte provided poor control and Broadstar provided almost no control. By 14 DAT, control declined for the low quinoclamine rate (1 oz./gal) while control was excellent in containers treated with 2 or 4 oz./gal. At this time, the only living remnants of the liverwort were female sporocarps. The entire thallus (leaf-like structures) were dead. By 45 DAT, control began to decline in containers treated with 1 and 2 oz./gal while control was still high among containers treated with 4 oz./gal.

Liverwort control 2 days after herbicide application.

Liverwort regrowth 45 days after herbicide application.

The images above, from right to left, show liverwort 14 days after application in non-treated controls, plants treated with 1 oz./gal, 2 oz./gal, and 4 oz./gal.

It has been noted that some postemergence herbicides provide 100% control of the liverwort thallus, but poor control of gemmae (personal communication with Sven Svenson). It is uncertain whether liverwort in containers treated with 1 or 2 oz./gal. regenerated from gemmae that remained viable after herbicide application, or if they were formed by subsequently introduced spores. If recolonization of liverwort in these containers are from germinating spores, lack of recolonization in containers treated with 4 oz./gal might indicate residual preemergence control at higher rates. This will be a focus of next year's research.


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