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Evaluation of V-10142 (Imazosulfuron) for yellow nutsedge
control in
potatoes
Joel Felix and Joey Ishida
Malheur Experiment Station
Oregon State University
Ontario,
OR,
2007
Introduction
Weeds are a major production problem for potato growers in eastern Oregon and other parts of the world. If not controlled in a timely manner, weeds can reduce tuber yields through direct competition with the crop for light, moisture, and nutrients, and may harbor insects and diseases that affect potatoes. Growers are always looking for newer and better herbicides to control weeds, especially in the earlier part of the growing season when newly emerged potato plants are vulnerable to competition. Products that control yellow nutsedge are especially sought by growers in eastern Oregon where the weed is widely distributed. Control of yellow nutsedge is extremely critical and a major emphasis is to use soil residual herbicides before the weeds emerge and establish to compete with the crop. If left uncontrolled, yellow nutsedge will reduce potato tuber yield and most importantly, it will produce more tubers that help to sustain its distribution in the field. There are reports that yellow nutsedge rhizomes can penetrate potato tubers and lower both yield and quality (Boldt 1976).
The varieties grown
for processing
in Malheur County, Oregon are mainly 'Ranger Russet', 'Shepody',
and 'Russet Burbank'. Potatoes are generally planted
in late March in beds formed during the previous fall.
All soil-applied herbicides are sprayed and incorporated
before potato emergence. The herbicide tested in this
study, V-10142, is soil applied but does not require incorporation,
and as such will reduce field activities.
Materials and
Methods
A field study was
established in a
grower field planted to Russet Burbank near Adrian, Oregon. The
objective was to determine the most efficient rates, timings, and
phytotoxicity of V-10142 herbicide when applied to potatoes alone
and in combinations with other herbicides. The study
was laid out in a randomized complete block design with four
replications; individual plots measured 9 ft wide by 30 ft long.
The potatoes were planted in 30-inch beds on April 6
and emerged on May 7, 2007. Pre-emergence (PRE)
treatments were applied on April 30 using a CO2 sprayer
with a boom fitted with four EVS 8002 flat-fan nozzles.
There was no incorporation of the herbicides after
applications were done. All postemergence (POST)
treatments included methylated seed oil (MSO) at 1 percent V/V and
were applied on May 24, 2007 when potato seedling height was about
6 inches and yellow nutsedge was about 4 inches high.
Evaluations for phytotoxicity and yellow nutsedge control were done
at 7, 14, and 46 days after treatment (DAT).
Evaluations were based on visual estimates on a 0-100 percent (0 =
no crop phytotoxicity or weed control and 100 = total crop injury
or excellent weed control). The data were subjected
to analysis of variance and means separated using the least
significant difference (LSD) at P = 0.05 percent.
Potatoes received overhead irrigation to keep the soil moist and
were fertilized and sprayed for insect and disease prevention using
recommended production practices for the area.
Potatoes were harvested at maturity from the center row, graded
following USDA standards, and specific gravity was
determined.
Results and
Discussion
There was no evident
potato injury
with any of the V-10142 treatments at any of the evaluation dates
(Table 1). The best yellow nutsedge control was
observed when a sequential application of PRE was followed by a
POST application of V-10142. Yellow nutsedge control
was low when V-10142 was applied PRE at 6.4 oz/acre.
Yellow nutsedge control at the time of potato canopy closure tended
to be greater with sequential applications of V-10142 applied PRE
and POST than with single applications of V-10142 applied
PRE. Control of yellow nutsedge by
sequential applications at 21 DAT ranged from 88 to 94 percent and
was similar to that provided by the standard herbicide application
of Eptam® plus Prowl® H2O plus Dual
Magnum® at 4.5 plus 1.58 plus 1.0 pt/acre,
respectively. A similar trend was observed for the
evaluations at potato row closure (July 9, 2007).
With the exception of the lowest rate of V-10142 applied PRE, all
herbicide treatments increased the marketable potato tuber yield
compared to the untreated control (Table 2). Tuber
yields tended to be greater with sequential application of V-10142
PRE followed by POST than PRE alone. The herbicide
V-10142 has potential to become a valuable product for yellow
nutsedge control in potato.
References
Boldt, P.F. 1976. Factors influencing the selectivity of U-compounds on yellow nutsedge. M. S. Thesis, Cornell University, Ithaca, NY.
Table 1. Potato response to V-10142 herbicide and yellow nutsedge control on June 1 and 7, 2007 at the Malheur Experiment Station, Oregon State University, Ontario, OR.
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Potato |
Yellow nutsedge |
Potato |
Yellow nutsedge |
||||||||
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|
---------------------- 6/1/2007 ---------------------- |
---------------------- 6/7/2007 ---------------------- |
||||||||||
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|
Chlorosis |
Necrosis |
Growth reduction |
Control |
Chlorosis |
Necrosis |
Growth reduction |
Control |
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|
Treatmenta |
Rate |
Timingb |
------------------------- % ------------------------- |
------------------------- % ------------------------- |
|||||||
|
1 |
V10142 |
6.4 |
oz/acre |
PRE |
0.0 |
0.0 |
0.0 |
50.0 |
0.0 |
0.0 |
0.0 |
50.0 |
|
2 |
V10142 |
8.5 |
oz/acre |
PRE |
0.0 |
0.0 |
0.0 |
77.5 |
0.0 |
0.0 |
0.0 |
78.8 |
|
3 |
V10142 |
10.7 |
oz/acre |
PRE |
0.0 |
0.0 |
0.0 |
70.0 |
0.0 |
0.0 |
0.0 |
72.5 |
|
4 |
V10142 |
6.4 |
oz/acre |
PRE |
0.0 |
0.0 |
0.0 |
86.3 |
0.0 |
0.0 |
0.0 |
78.8 |
|
|
V10142 |
6.4 |
oz/acre |
POST |
|
|
|
|
|
|
|
|
|
|
MSO |
1.6 |
pt/acre |
POST |
|
|
|
|
|
|
|
|
|
5 |
V10142 |
8.5 |
oz/acre |
PRE |
0.0 |
0.0 |
0.0 |
90.0 |
0.0 |
0.0 |
0.0 |
87.5 |
|
|
V10142 |
8.5 |
oz/acre |
POST |
|
|
|
|
|
|
|
|
|
|
MSO |
1.6 |
pt/acre |
POST |
|
|
|
|
|
|
|
|
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6 |
V10142 |
10.7 |
oz/acre |
PRE |
0.0 |
0.0 |
0.0 |
95.0 |
0.0 |
0.0 |
0.0 |
90.0 |
|
|
V10142 |
10.7 |
oz/acre |
POST |
|
|
|
|
|
|
|
|
|
|
MSO |
1.6 |
pt/acre |
POST |
|
|
|
|
|
|
|
|
|
7 |
V10142 |
6.4 |
oz/acre |
PRE |
0.0 |
0.0 |
0.0 |
92.5 |
0.0 |
0.0 |
0.0 |
90.0 |
|
|
D. Magnum |
1.0 |
pt/acre |
PRE |
|
|
|
|
|
|
|
|
|
|
V10142 |
8.5 |
oz/acre |
POST |
|
|
|
|
|
|
|
|
|
|
MSO |
1.6 |
pt/acre |
POST |
|
|
|
|
|
|
|
|
|
8 |
Matrix |
1.0 |
oz/acre |
PRE |
0.0 |
0.0 |
0.0 |
86.3 |
0.0 |
0.0 |
0.0 |
81.3 |
|
|
D. Magnum |
1.0 |
pt/acre |
PRE |
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|
|
|
|
|
|
|
|
|
Matrix |
1.0 |
oz/acre |
POST |
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|
|
|
|
|
|
|
|
|
MSO |
1.6 |
pt/acre |
POST |
|
|
|
|
|
|
|
|
|
9 |
D. Magnum |
1.0 |
pt/acre |
PRE |
0.0 |
0.0 |
0.0 |
90.0 |
0.0 |
0.0 |
0.0 |
81.3 |
|
|
Sencor 4 |
0.38 |
pt/acre |
PRE |
|
|
|
|
|
|
|
|
|
|
V10142 |
8.5 |
oz/acre |
POST |
|
|
|
|
|
|
|
|
|
|
MSO |
1.6 |
pt/acre |
POST |
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|
|
|
|
|
|
|
10 |
D. Magnum |
1.0 |
pt/acre |
PRE |
0.0 |
0.0 |
0.0 |
93.8 |
0.0 |
0.0 |
0.0 |
88.8 |
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|
Sencor 4 |
0.38 |
pt/acre |
PRE |
|
|
|
|
|
|
|
|
|
|
Matrix |
1.0 |
oz/acre |
POST |
|
|
|
|
|
|
|
|
|
|
MSO |
1.6 |
pt/acre |
POST |
|
|
|
|
|
|
|
|
|
11 |
Eptam 7E |
4.5 |
pt/acre |
PRE |
0.0 |
0.0 |
0.0 |
78.8 |
0.0 |
0.0 |
0.0 |
63.8 |
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|
Prowl H2O |
1.58 |
pt/acre |
PRE |
|
|
|
|
|
|
|
|
|
|
D. Magnum |
1.0 |
pt/acre |
PRE |
|
|
|
|
|
|
|
|
|
12 |
untreated |
|
|
|
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
|
LSD (P = 0.05) |
-- |
-- |
-- |
12.35 |
-- |
-- |
-- |
18.82 |
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Standard Deviation |
-- |
-- |
-- |
8.55 |
-- |
-- |
-- |
13.02 |
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CV |
-- |
-- |
-- |
11.28 |
-- |
-- |
-- |
18.13 |
||||
aMSO = Methylated seed oil; D. Magnum = Dual Magnum.
bTiming PRE = Pre-emergence, POST = Post-emergence.
Table 1 continued. Potato response to V-10142 herbicide and yellow nutsedge control on June 14 and July 9, 2007 at the Malheur Experiment Station, Oregon State University, Ontario, OR.
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-------------------- Potato ---------------------- |
-------- Yellow nutsedge -------- |
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------------------ 6/14/2007 ------------------- |
6/14/2007 |
7/9/2007 |
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|
Chlorosis |
Necrosis |
Growth reduction |
Control |
Control |
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Treatmenta |
Rate |
|
Timingb |
------------------------ % ------------------------ |
------------------ % ------------------ |
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1 |
V10142 |
6.4 |
oz/acre |
PRE |
0.0 |
0.0 |
0.0 |
55.0 |
65.0 |
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2 |
V10142 |
8.5 |
oz/acre |
PRE |
0.0 |
0.0 |
0.0 |
75.0 |
78.8 |
|
3 |
V10142 |
10.7 |
oz/acre |
PRE |
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