Vol. 51—1997 - NorthEastern Weed Science Society

26
NmlUAL WEED CONTROL WITH EXP 31130A IN 1995 AND 1996
UNDER NO-TILLAGE SYSTEM IN CORN
P. C. Bhowmik and R. G. Prostak 1
ABSTRACT
Fie d experiments were conducted in 1995 and 1996 to determine the effectiveness of
EXP 3113 A in controlling annual grass and broadleaf weeds in field com under a no-tillage
system. 1995, EXP 31130A was evaluated alone at 1.5, 1.88, 2.25 and 3.0 oz ailA and in
combinati ns at 1.5 and 2.25 oz ailA with either acetoehlor or metolachlor at LOibl A. Large
crabgrass .. . sanl:uinalisL. Scop.), yellow foxtail [Setaria lutesceus (Weigel) Rubb.], fall
panicum . m dichotomiflorum Michx.), common lambquarters (ChenQ,pOdiumillmmL.)
and horse eed [Conyza canadensis (L.) Cronq.] were present at the study site. In 1996, EXP
31130A w evaluated alone at 1.5 and 1.88 oz ailA and in combinations with 1.0 and 1.5 Ib/A
of acetoeh r and with 1.25 and 1.88 lblA of metolachlor. Glyphosate at 1.5 IblA was applied
over the ntire area prior to no-till planting. Large crabgrass, yellow foxtail, common
lambq rs, redroot pigweed (Amaranthus retroflexus L.), galinsoga (Galinsoga paryiflora
Cav.), and common ragweed (Ambrosia artemisiifolia L.) were present. Plots were 6.7' by 20'
and the tr tments were replicated three times in a randomized complete block design. With a
no-till pI ter 'Ciba 4385' com ~~L.) was planted on May 9, 1995 and 'Max 747' was
planted 0 May 20, 1996. Treatments were applied preemergence, using a CO 2-backpack
sprayer t delivered 20 gpa at 22 psi. Corn height was determined 5 and 9 WAT (weeks after
treatment) Weed control was estimated on a scale of 0 to 100% 2, 4 and 8 WAT in 1995 and
3, 7, and 4 WAT in 1996. Silage and grain yields were also determined.
In 995, no com injury was observed with any of the EXP 31130A treatments. All
treatments effectively controlled yellow foxtail, large crabgrass, fall panicum, lambquarters,
pigweed d horseweed 2, 4 and 6 WAT. EXP 31130A treatments either alone or in
combinati ns without atrazine did not control sulfur cinquefoil (Potentilla ~ L.). All
treatments effectively controlled common chickweed [Stellaria~ (L.) Vill.] 2 WAT. In
1996, E 31130A at 1.5 and 1.88 oz ailA or in combinations with either acetoehlor at 1.0 and
1.5 Ib/A, r with metolachlor at 1.25 and 1.88 Ib/A, or with atrazine at 1.25 and 2.0 Ib/A
controlled large crabgrass, yellow foxtail, common lambsquarters, redroot pigweed, common
ragweed, alinsoga effectively 3, 7, and 14 WAT. The 1.5 ozlA rate ofEXP 31130A provided
only over 0% control of common ragweed.
31130A alone at 1.5 to 3.0 ozlA resulted in corn grain yields from 51 to 132 bu/A
in 1995 d 105 to 117 bu/A in 1996, and silage yields from 9 to 21 ton/A in 1995 and 17 to
20 ton/A i 1996. The highest grain yields (178 to 206 bu/A) and silage yields (28 to 32 ton/A)
were ob ned from atrazine combinations with either metolachlor or acetochlor, while the
highest g . yield (160 bulA) and silage yield (26 tons/A) were obtained with the treatment
combinati ns of EXP 31130A, metolachlor and atrazine at 1.5 oz/A, 1.25 and 1.25 lb/A.
'Professo and Technician, Department of Plant and Soil Sciences, University of Massachusetts,
Amherst, 01003