Vol. 16—1962 - NorthEastern Weed Science Society

16
SOMECHARACTERISTICS OF QUACKQR4SS ArID THEIRRELATIONTO CONTROLY
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K. P. ElUchholtz y' ·,_,.i"
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QuaeJcgrass is a widely distributed end persietent'weedili the northern
states arid Canada. .It has proved to be adapted to 'Cobt,. temperate n!gions
and lsfevoi'ed .by' hUmid or subJ.!tIum1dcUinstell." 1he;weed is IOOsttroubl8some
in areas thatdare subjected tcqlerlodic 1 but'no,t; ,cxmtinuous tillage. It Competes
stronglY with forage cropS',; gn-ins, com··1tt!d'other row crops', f'J:'lrl,ts,
and: vegetables. !:t is objectionable in forestry p1:antations, laws, 'llndindustria~
sites.
In ordert,(, develop effecti.~Controlprogr,.ror qusckgra ss it, i8
necessary ,to' consider the fectors that account,tb-r1ts adaptation in,.the'
northe~ states and the reaso,ns for its pers;l.stene;:e•. ' Quackgrass spre8~')
by both rb1'ZOIlIeS, and seeds. It iSl'robehlethat ~ad by seeds is J1I!)rj:_
w;idespreadthanis generally rElaJ;tzed. Because or':aimi.larity in shape,t,!'1~
seed is more cOll!lOOn in oats than itl seed of other'icereals. In 1957 a stUdy
in Wisconsin showed that 35%of 799 oat samples handled by the State Seed
Testing Laboratory in that year contained qusckgrass seeds. Seeder box
surveys of oats being seeded have consistently shown that from 50~ to 60%of
the grain being used as seed in Wisconsin is infested with qusckgrass seed.
Viability of quackgrass seed in seed grain was frequently as high as that
of the oats. In addition to the spread in seed grain the mature seeds of
quackgrass are frequently harvested with hay and ultimately find their way
back to the field in manure or bedding. Seeds also mature in pastures where
they shatter readily and infest the soil. The prevalence and vJ.abil1ty of
qusckgrass seeds often allows reinfestetion aftsr all established plants
hava been eradicated.
The ability of quackgrass to spread by rhizomes is widely recognized.
These spreading underground stems may extend as 1IIUChas 3 or 4 feet in a single
year. Tillage often extends the area of infestation IllUchfarther than this
by dragging fragments of the rhizomes beyond the area of initial infestation.
Rhizome production is prolific in a productive soil. Meyer (9), Schirman
and Buchholtz (14) and Johnson (4) all found as much as 6000 lblA of dry
rhizomes in heavily infested areas. This mass of rhizomes was contained in
the plow slice and in an undisturbed sod was concentrated in the upper 4
inches of so11.
The life of a particular rhizome is not as long as would be expected.
Sagar (13) mentioned that the rhizomes may live for 3 years in England, but
seldom longer. Johnson and Buchholtz (6) found no evidence that the rhizomes
lived more than 2 years under IOOrerigorous conditione in Wisconsin and a
large proportion of them lived no longer than 1 year. The fact that the rhizomes
are relatively short-lived is a vulnerable point in the life cycle of
the weed. If new rhizome growth could be limited or eliminated for 1 year,
the persistence of the weed would be sharply reduced.
11Published with the approval of the Director of the Wisconsin Agricultural
Experiment Station as a collaborator under Horth Central Regional Coop-
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