Vol. 51—1997 - NorthEastern Weed Science Society

100
LIVERWORT AND PEARLWORT MANAGEMENT
IN CONTAINER-GROWN
PERENNIALS
Andrew Senesac and Irene Tsontakis-Bradley'
ABSTRACT
Liverwort (Marchantia ~.) and birdseye pearlwort (Sagina
r c m n 1.); although taxonomically very different, are often found
coexist' g as troublesome weeds in container-grown perennials. This study was
conduc d to evaluate control strategies for these weeds which could be adapted
to nurs ries growing many species of perennials.
A container study was conducted in 1996 at the Long Island
Horticu tural Research Laboratory to assess the efficacy of several herbicides for
liverwo t and pearlwort control. Liverwort and pearlwort were grown in 20" X
14" flat in a potting soil mix under shade and irrigated daily and fertilized
weekly. While the pearlwort was overseeded, the liverwort infestation was
achieve by drenching with a slurry of ground thallose (vegetative) tissue and
water.
reemergence treatments were all applied on the day of infestation.
The treatments consisted of: prodiamine 65 WDG at 1.5 lb/a (a.i),
dithiop 1 EC at 0.5 lb/a, oxadiazon 2G at 3.0 Ib/a, napropamide 5G at 4.0 lb/a,
oryzali 4 AS at 3.0 lb/a, sulfentrazone 80 WP at 0.25 lb/a, oryzalin plus
naprop mide plus oxadiazon at 1.0+1.5+1.0 lb/a J oryzalin plus dithiopyr plus
oxadiaz nat 1.0 + 0.175 + 1.0 lb/a, and napropamide plus oxadiazon at 4.0 + 2.0
lb/a.
The results of visual evaluations of percent ground cover several
weeks fter treatment indicate that oryzalin alone and oryzalin in either
combin tion were most effective in controlling both liverwort and pearlwort.
Both di hiopyr and oxadiazon controlled liverwort very well, but were fair and
poor, r spectively for pearlwort control. Prodiamine provided excellent control
of pear wort but was only fair on liverwort. Sulfentrazone and napropamide
were n t effective in controlling either weed.
Science Specialist and Research Technician, Cornell Cooperative
Exte ion, Long Island Horticultural Research Laboratory, Riverhead, NY