|
|
WEED CONTROL
AND CROP RESPONSE WITH OPTION® HERBICIDE
APPLIED IN
FIELD CORN
Corey
V. Ransom, Charles A. Rice, and Joey K. Ishida
Malheur
Experiment Station
Oregon
State University
Ontario,
OR, 2004
Introduction
Weed control is important in field corn production to reduce competition with the crop and to prevent the production of weed seed for future crops. Field trials were conducted to evaluate Option® (foramsulfuron) herbicide applied alone and in various combinations for weed control and crop tolerance in furrow-irrigated field corn. Option is a new postemergence sulfonylurea herbicide that controls annual and perennial grass and broadleaf weeds in field corn. Option contains a safener that is intended to enhance the ability of corn to recover from any yellowing or stunting sometimes associated with the application of sulfonylurea herbicides.
Materials and
Methods
The soil was formed into 22-inch beds
on May 10. Plots were sidedressed with
126 lb nitrogen (N), 14 lb sulfates, 3 lb zinc, 1 lb boron, 1 lb manganese, and
38 lb elemental sulfur/acre on May 11. Pioneer
variety ‘P-36N69’ Roundup Ready®
field corn was planted with a John Deere model 71 Flexi Planter on May 17. Seed spacing was one seed every 7 inches. Plots were 7.33 by 30 ft and herbicide
treatments were arranged in a randomized complete block with four
replicates. Herbicide treatments were
applied with a CO2-pressurized backpack sprayer calibrated to
deliver 20 gal/acre at 30 psi. Crop
response and weed control were evaluated throughout the growing season. Corn yields were determined by harvesting
ears from 26-ft sections of the center 2 rows in each 4-row plot on October 11. The harvested ears were shelled and grain
weight and percent moisture content were recorded. Grain yields were adjusted to 12 percent moisture content. Data were analyzed using analysis of
variance (ANOVA) and treatment means were separated using Fisher’s protected
least significant difference (LSD) at the 5 percent level (P = 0.05).
Postemergence treatments of Option,
Clarion®, or Roundup® were applied alone and in
combinations with other herbicides and with or without preemergence (PRE) Dual
Magnum®. PRE applications were made May 21. Mid-postemergence (MP) treatments were
applied to corn at the V4 growth stage on June 11, and late postemergence
treatments (LP) were applied to corn at the V6 growth stage on June 19. Option was applied with various additives as
well as in combination with Distinct®
or Callisto®. Option combinations were compared to Clarion
applied alone and in combination with Distinct or to Roundup applied alone or
following PRE Dual Magnum. The
herbicide rates and combinations are shown in Table 1.
Results and Discussion
Control of pigweed
species (i.e., Powell amaranth and redroot pigweed) ranged from 91 to 100
percent on July 23 and was similar among herbicide treatments. One exception was
the treatment with Option, Dyne-Amic®, and 32 percent N, which provided only 91 percent control
(Table 1). When Option was applied with
Dyne-Amic and 32 percent N or Quest®, common lambsquarters control also was lower than all other
treatments. Clarion alone also provided
less common lambsquarters control than all other treatments except for Option
applied with Dyne-Amic. Combinations of
Option with Distinct or Callisto, and the combination of Clarion and Distinct provided
among the best common lamsquarters control.
Common lambsquarters control was improved when Roundup was applied
following PRE Dual Magnum compared to Roundup applied alone. Clarion alone provided the least hairy
nightshade control, and the combination of Clarion and Distinct also provided
less hairy nightshade control compared to all other treatments except Option
with Dyne-Amic and 32 percent N. There
were no significant differences in kochia and barnyardgrass control among
treatments.
Injury from herbicide
treatments ranged from 0 to 14 percent on June 19 and was 4 percent or less on
July 2 (Table 2). Corn yields ranged
from a low of 103 bu/acre with the untreated control to a high of 194 bu/acre
with the combination of Option and Callisto (Table 2). The treatment containing Option with
Dyne-Amic and 32 percent N had lower yields than many of the other Option
treatments and was likely due to reduced weed control with that treatment.
The selection of
additives can significantly affect the efficacy of Option against pigweed
species, common lambsquarters, and hairy nightshade. The addition of Distinct or Callisto to Option can significantly
improve common lambsquarters control.
Table 1. Weed control with Option® herbicide applied in field corn, Malheur
Experiment Station, Oregon State University, Ontario, OR, 2004.
|
|
|
|
Weed control§ |
||||||||
|
Treatment |
Rate* |
Timing† |
Pigweed spp‡ |
|
C. lambs- quarters |
|
H. night- shade |
|
Kochia |
|
Barnyard- grass |
|
|
lb ai/acre pt/acre % v/v |
|
------------------------------------- % -------------------------------------- |
||||||||
|
Option + MSO + 32% N |
0.033 + 1.5 + 3.0 |
MP |
100 |
|
79 |
|
92 |
|
96 |
|
97 |
|
Option + MSO + AMS |
0.033 + 1.5 + 3.0 |
MP |
100 |
|
88 |
|
99 |
|
97 |
|
100 |
|
Option + DYNE-AMIC + 32% N |
0.033 + 0.25% + 3.0 |
MP |
91 |
|
45 |
|
76 |
|
95 |
|
94 |
|
Option + MSO + QUEST |
0.033 + 1.5 +2.5% |
MP |
98 |
|
89 |
|
98 |
|
100 |
|
97 |
|
Clarion + MSO + 32% N |
0.023 + 1.5 +4 |
MP |
98 |
|
61 |
|
52 |
|
98 |
|
99 |
|
Option + MSO + 32% N |
0.033 + 1.5 +3.0 |
MP |
99 |
|
89 |
|
94 |
|
100 |
|
97 |
|
Option + Distinct +
MSO + 32% N |
0.033 + 0.088 + 1.5 + 3.0 |
MP |
100 |
|
100 |
|
96 |
|
100 |
|
96 |
|
Option + Distinct +
MSO + 32% N |
0.33 + 0.175 + 1.5 + 3.0 |
MP |
100 |
|
100 |
|
99 |
|
100 |
|
97 |
|
Clarion + Distinct
+ NIS + 32% N |
0.023 + 0.088 + 0.5% + 4.0 |
MP |
100 |
|
97 |
|
73 |
|
100 |
|
100 |
|
Option + Callisto +
MSO + 32% N |
0.033 + 0.0625 + 1.5 + 3.0 |
MP |
99 |
|
100 |
|
97 |
|
100 |
|
98 |
|
Dual II Magnum Option + MSO + 32% N |
1.6 0.033 + 1.5 + 3.0 |
PRE LP |
97 |
|
90 |
|
85 |
|
100 |
|
100 |
|
Option + MSO + AMS |
0.033
+ 1.5 +3 |
MP |
99 |
|
88 |
|
97 |
|
99 |
|
96 |
|
Option + DYNE-AMIC + Quest |
0.033
+ 0.25 % + 0.25% |
MP |
97 |
|
48 |
|
88 |
|
99 |
|
100 |
|
Roundup Ultramax |
0.58 |
MP |
99 |
|
81 |
|
95 |
|
100 |
|
97 |
|
Dual II Magnum Roundup Ultramax + AMS |
1.6 0.58
+ 3.0 |
PRE LP |
100 |
|
92 |
|
90 |
|
100 |
|
99 |
|
LSD (0.05) |
|
|
3 |
|
6 |
|
11 |
|
NS |
|
NS |
*Herbicide
rates are in lb ai/acre. Additive rates
are in pt/acre or percent v/v.
†Application timings were preemergence
(PRE) on May 21, mid-postemergence (MP) applied to corn at the V4 growth stage
on June 11, and late postemergence (LP) to corn at the V6 growth stage on June
19.
‡Pigweed species were a mixture of Powell amaranth and
redroot pigweed.
§Weed control was evaluated July 23. The untreated control was not included in
the ANOVA for weed control.
Table 2. Injury and yield with Option® herbicide applied in field corn, Malheur
Experiment Station, Oregon State University, Ontario, OR, 2004.
|
|
|
|
Field corn |
|||||
|
|
|
|
Injury‡ |
|
|
|
Yield§ |
|
|
Treatment |
Rate* |
Timing† |
6-19 |
7-2 |
|
|
|
|
|
|
lb ai/acre pt/acre % v/v |
|
------------------- % ----------------- |
|
|
|
bu/acre |
|
|
Untreated control |
-- |
-- |
-- |
-- |
|
|
|
103 |
|
Option + MSO + 32% N |
0.033 + 1.5 + 3.0 |
MP |
8 |
0 |
|
|
|
179 |
|
Option + MSO + AMS |
0.033 + 1.5 + 3.0 |
MP |
9 |
0 |
|
|
|
187 |
|
Option + DYNE-AMIC + 32% N |
0.033 + 0.25% + 3.0 |
MP |
5 |
0 |
|
|
|
157 |
|
Option + MSO + QUEST |
0.033 + 1.5 +2.5% |
MP |
10 |
0 |
|
|
|
192 |
|
Clarion + MSO + 32% N |
0.023 + 1.5 +4 |
MP |
3 |
0 |
|
|
|
178 |
|
Option + MSO + 32% N |
0.033 + 1.5 +3.0 |
MP |
9 |
3 |
|
|
|
174 |
|
Option + Distinct +
MSO + 32% N |
0.033 + 0.088 + 1.5 + 3.0 |
MP |
11 |
0 |
|
|
|
183 |
|
Option + Distinct +
MSO + 32% N |
0.33 + 0.175 + 1.5 + 3.0 |
MP |
14 |
4 |
|
|
|
178 |
|
Clarion + Distinct
+ NIS + 32% N |
0.023 + 0.088 + 0.5% + 4.0 |
MP |
6 |
1 |
|
|
|
189 |
|
Option + Callisto +
MSO + 32% N |
0.033 + 0.0625 + 1.5 + 3.0 |
MP |
5 |
0 |
|
|
|
194 |
|
Dual II Magnum Option + MSO + 32% N |
1.6 0.033 + 1.5 + 3.0 |
PRE LP |
9 |
3 |
|
|
|
184 |
|
Option + MSO + AMS dry |
0.033
+ 1.5 +3 |
MP |
9 |
0 |
|
|
|
178 |
|
Option + DYNE-AMIC + Quest |
0.033
+ 0.25 % + 0.25% |
|||||||
