Oakes Irrigation Research Site
Carrington Research Extension Center * North Dakota State University
P.O. Box 531, Oakes, ND 58474-0531, Phone: (701) 742-2744, FAX: (701) 742-2700, E-mail: Blaine.Schatz@ndsu.edu
Leonard.Besemann@ndsu.edu
Metribuzin and Rimsulfuron for Eastern Black Nightshade Weed Control on Potato
H. Hatterman-Valenti and C. Auwarter
     This study was conducted at the Oakes Irrigation Research Site near Oakes, ND, to evaluate different rates of metribuzin and rimsulfuron applied POST (B-E) on Russet Burbank potatoes for eastern black nightshade control.  Some treatments received a PRE (A) application of flumioxazin tank mixed with metribuzin at a rate of 0.3875 oz and 0.6 lb/ac.  Corn was grown during 2012.  Plots were 4 rows by 20 ft arranged in a randomized complete block design with four replicates.  Seed pieces (2 oz) were planted on 36-inch rows and 12-inch spacing on May 15, 2013.  Potatoes were harvested on October 29.  Spray applications, yield data and weed control ratings are listed below.
Table 1.  Application details.
Date: 6/14/2013 6/22/2013 7/1/2013 7/8/2013 7/16/2013
Timing: A B C D E
Sprayer: GPA: 20 20 20 20 20
PSI: 40 40 40 40 40
Nozzle: 8002 8002 8002 8002 8002
Air Temp. (F): 81 74 83 80 82
Rel. Hum. (%): 51 81 35 54 63
Wind (MPH): 11 9 4 5 9
Table 2.  Yield data.
Trt No Row A Row B Row A Row B
------------20’------------ -------CWT/ac-------
1 59.80 63.90 434.2 463.9
2 74.00 74.63 537.2 541.8
3 73.75 74.15 535.4 538.3
4 76.53 81.58 555.6 592.3
5 59.73 67.65 433.6 491.1
6 62.43 72.15 453.2 523.8
7 69.40 67.33 503.8 488.8
8 68.68 74.03 498.6 537.5
9 67.35 69.90 489 507.5
LSD (P = 0.05) 13.59 14.70 98.7 106.7
         PRE applications of flumioxazin tank mixed with metribuzin had better weed control 14 days after application (DAA) A and 6 DAA B.  Applying a single application of metribuzin at 1.5 oz/ac tank mixed with Matrix at 0.5 lb/ac did just as well as multiple applications of the same tank mix and same amount of total product throughout the trial.  The untreated had the lowest yield while the highest yielding treatment had three applications of metribuzin at 0.5 oz/ac tank mixed with Matrix at 0.167 lb/ac.
Table 3.  Treatments and weed control ratings.
          % Control
Trt Trt Rate/ ------------6/28/2013------------ ------------7/16/2013------------ ------------8/14/2013------------
No. Name Rate Unit App COLQ1 RRPW2 EBNS3 GRFT4 COLQ RRPW EBNS GRFT COLQ RRPW EBNS GRFT
                                 
1 Untreated       0 c 0 c 0 d 0 b 0 b 0 b 0 b 0 c 0 b 0 b 0 b 0 b
2 Class Act NG 2.5 %v/v B 93 ab5 94 ab 90 c 99 a 100 a 100 a 99 a 100 a 95 a 100 a 98 a 100 a
  Metribuzin 1.5 oz/A B                      
  Matrix 0.5 lb/A B                        
3 Class Act NG 2.5 %v/v B 85 b 94 ab 93 bc 98 a 91 a 100 a 93 a 100 a 96 a 100 a 100 a 99 a
  Metribuzin 0.75 oz/A B                      
  Matrix 0.25 lb/A B                      
  Class Act NG 2.5 %v/v D                      
  Metribuzin 0.75 oz/A D                      
  Matrix 0.25 lb/A D                      
4 Class Act NG 2.5 %v/v B 91 ab 94 ab 93 bc 99 a 95 a 100 a 98 a 100 a 98 a 100 a 100 a 100 a
  Metribuzin 0.5 oz/A B                      
  Matrix 0.167 lb/A B                      
  Class Act NG 2.5 %v/v C                      
  Metribuzin 0.5 oz/A C                      
  Matrix 0.167 lb/A C                      
  Class Act NG 2.5 %v/v D                      
  Metribuzin 0.5 oz/A D                      
  Matrix 0.167 lb/A D                      
5 Class Act NG 2.5 %v/v B 85 b 90 b 89 c 98 a 95 a 100 a 98 a 100 a 98 a 99 a 100 a 98 a
  Metribuzin 0.375 oz/A B                      
  Matrix 0.125 lb/A B                      
  Class Act NG 2.5 %v/v C                      
  Metribuzin 0.375 oz/A C                      
  Matrix 0.125 lb/A C                      
  Class Act NG 2.5 %v/v D                      
  Metribuzin 0.375 oz/A D                      
  Matrix 0.125 lb/A D                      
  Class Act NG 2.5 %v/v E                      
  Metribuzin 0.375 oz/A E                      
  Matrix 0.125 lb/A E                      
6 Chateau 0.75 oz/A A 99 a 100 a 98 ab 100 a 95 a 100 a 95 a 98 b 100 a 100 a 100 a 99 a
  Metribuzin 0.6 lb/A A                    
  Class Act NG 2.5 %v/v B                    
  Metribuzin 0.75 oz/A B                    
  Matrix 0.25 lb/A B                        
7 Chateau 0.75 oz/A A 100 a 96 a 94 bc 100 a 100 a 100 a 100 a 100 a 100 a 100 a 100 a 100 a
  Metribuzin 0.60 lb/A A                    
  Class Act NG 2.50 %v/v B                    
  Metribuzin 0.75 oz/A B                    
  Matrix 0.25 lb/A B                    
  Class Act NG 2.50 %v/v D                    
  Metribuzin 0.75 oz/A D                    
  Matrix 0.25 lb/A D                        
8 Chateau 0.75 oz/A A 100 a 99 a 100 a 100 a 100 a 100 a 100 a 100 a 100 a 100 a 100 a 100 a
  Metribuzin 0.60 lb/A A                      
  Class Act NG 2.50 %v/v B                      
  Metribuzin 0.75 oz/A B                      
  Matrix 0.25 lb/A B                      
  Class Act NG 2.50 %v/v C                      
  Metribuzin 0.75 oz/A C                      
  Matrix 0.25 lb/A C                      
  Class Act NG 2.50 %v/v D                      
  Metribuzin 0.75 oz/A D                      
  Matrix 0.25 lb/A D                        
9 Chateau 0.75 oz/A A 98 a 98 a 94 bc 100 a 100 a 100 a 100 a 100 a 100 a 100 a 100 a 100 a
  Metribuzin 0.60 lb/A A                    
  Class Act NG 2.50 %v/v B                    
  Metribuzin 0.75 oz/A B                    
  Matrix 0.25 lb/A B                    
  Class Act NG 2.50 %v/v C                    
  Metribuzin 0.75 oz/A C                    
  Matrix 0.25 lb/A C                    
  Class Act NG 2.50 %v/v D                    
  Metribuzin 0.75 oz/A D                    
  Matrix 0.25 lb/A D                    
  Class Act NG 2.50 %v/v E                    
  Metribuzin 0.75 oz/A E                    
  Matrix 0.25 lb/A E                        
    LSD (P = 0.05) 7.05 4.15 4.62 3.08 7.66 0 7.55 1.4 5.25 1.22 2.43 3
1 COLQ = Common lambsquarter.
2 RRPW = Redroot Pigweed.
3 EBNS = Eastern black nightshade.
4 GRFT = Green foxtail.
5 Data followed by different letters are significantly different at P < 0.05.
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