Vol. 15—1961 - NorthEastern Weed Science Society

25S.
THEEFEECTOF ZYTl\uN ONS~EDJ..Lm
C. ft. Skogley2
nJkF GhilSSESI
Spring seeded la\~s are often beset with problems, chief amongwhich may
be competition with annual weed grasses. The elimination of this problem would
solve an age old dilemma. Very recently several herbdcddes have been introduced
that sho\1 promise of selectively controlling crabgrass when applied to established
grasses prior to the germination of the crabgrass seed. Zytron, known
chendcally as 0-(2,4-dichlorophenyl) O-methyl phosphoromidothioate, is one of
these materials. Little is knO\Yn about the value or use of this chemical with
seedling, grasses, however.
This test was established in order to preliminarily observe the effects of
Zytron on seedling grasses under field conditions.
Materials
and Methods
The test area was prepared and seeded on April 26, 1960. Eight different
grasses were included, and were seeded in adjacent strips each 6 x 60 feet in
size. The soil in the test area is classed as Jridgehampton silt loam and the
pH was adjusted to about 6.5. Twenty pounds of an 8-6-2 fertilizer was applied
per 1000 square feet and raked into the surface inch of soil prior to seeding.
The grasses included in the trial were Kentucky bluegrass (Poa pratensis) and
the }~rionvariety of Kentucky bluegrass, Creeping red and Chewingsfescue
(Festuca rubra), Kentucky 31 tall fescue Festuca arUndinacea), ~erennial ryegrass
(101ium perenne), Redtop (Agrostis !!2! ,and Astoria Colonia bentgrass
(Agrostis tenuis). The seeding rate was 3 p6undsper 1000 square feet for the
bluegrasses, 6 pounds for the red fescues, 10 pounds for tall fescue and the
ryegrass and 2 pounds for the agrostis species. The Agrostis species were mowed
at a height of one inch and all others \{ere cut at IJ.-inches.
Twofornlulations of Zytron were applied in ~{o foot strips over each species
of grass at 2, 4, 6, and 8 week intervals fron:the seeding date. Treatments were
in triplicate and each interval lias randomized within blocks. hl1 emulsifiable
concentrate (}~1329) containing 2 pounds active ingredient per gallon and a formulation
on vermiculite (}~1662) containing 8%active material were employed at
the rate of 20 pounds active per acre.'
Periodic obser.vati~n~. ~d rea&ings ·w.er~ :.~&de to observe and record seedling
and grass response to t~ 'treatments; Untreated ~ontrols were maintained as a
standard for comparison. Plant counts were taken on one replication on July 5 ­
~iO weeks after the last chemical application. Estimates of turf coverage were
made and root formation and penetration were studied in early November.
1 2Contribution No. 1015 of the Rhode Island Agricultural Experiment Station.
Associate Professor of Agronomy.