ISSUE 7   June 21, 2007

BASAGRAN - UNDERAPPRECIATED AND UNTAPPED

I have received many phone calls from dry bean growers how to control emerged common lambsquarters, kochia, and wild buckwheat. POST options of Basagran, Pursuit, Raptor, and Reflex is poor on one or more of these weeds. After growers refer to the weed guide (I assume) and see there no effective options they call me and ask if there is a crop safe and effective option (I assume legal options). I find these phone calls interesting, like I have a secret section of the weed guide that is unpublished, that no one knows about, and is filled with highly classified information that is deemed too sensitive for general distribution. There isnít a secret section to the weed guide and I usually donít have alternative options .... but in this case there is another option and the information is hidden on page 88 in the weed guide, paragraph D5.

"NDSU research has shown greater control of lambsquarters, redroot pigweed and kochia by applying Basagran as split treatments either twice each at 1 pt/A, 3 times each at 0.67 pt/A, or 4 times each at 0.5 pt/A as compared to one application at 2 pt/A. Basagran is safe to soybean at all stages."

Dr. Bill Ahrens, NDSU Weed Scientist, conducted the first "micro-rate" research with Basagran in dry beans in 1993-1997. Dr. Alan Dexter is thought of as the "Father of Micro-rate" technique but this pre-dates his use in sugarbeet. The information in the table below is based on Dr. Ahrenís research. Applications were made 7 days apart.

Multiple applications of Basagran in drybean, 1993-1997.

Basagran +

Rate

Colq

Koch

Rrpw

PO (COC)

0.5 pt x 4

76

98

99

PO

0.67 pt x 3

34

79

95

PO

1 pt x 2

31

64

90

PO

2 pt x 1

8

38

51

Dash (MSO)

0.5 pt x 4

99

98

98

Dash

0.67 pt x 3

79

100

100

Dash

1 pt/A x 2

76

98

95

Dash

2 pt x 1

5

86

92

AMS

0.5 pt x 4

53

86

97

AMS

0.67 x 3

9

31

95

AMS

1 pt x 2

5

0

0

AMS

2 pt x 1

2

0

0

Colq = common lambsquarters
Koch = kochia
Rrpw = redroot pigweed

Dash (MSO) adjuvant enhanced Basagran more than petroleum oil (COC) or AMS and 4 split applications of Basagran with MSO gave near complete control of all three weeds. I suspect that Basagran applied sequentially would also give greater control of many other weeds, including wild buckwheat, compared to one application at the full 2 pt/A rate. Of course, the technique can be used in all crops that Basagran is labeled. Other NDSU weed scientists and several graduate students have used the micro-rate approach with Raptor, Pursuit, and Reflex in dry bean to control nightshade and have shown similar increase in not only nightshade control but many other weeds from the sequential application technique.

Apply the first application when broadleaf weeds are small (<1 inch). Make applications 7 to 10 days apart depending on weed growth rate, environment, size of kochia at first application, sequential flushes, and degree of control from first application. Use 1 qt/A of oil adjuvant with each application. DO NOT reduce the rate of oil adjuvant. MSO adjuvant has shown greater enhancement of Basagran in some studies but the cost of MSO adjuvant is greater than petroleum oil (COC) adjuvants. The total maximum seasonal use rate is 4 pt/A so the micro-rate rates can be increased if weeds are large at application or if sequential timing is delayed due to rain or wind. For example, apply 0.67 or 1 pt/A four times sequentially.

It is more economical to use Rezult instead of Basagran because of the inclusion of Poast in Rezult. Basagran is a 4 lb/gal formulation but the Basagran in Rezult is a 5 lb/gal formulation. To use equal active ingredient rates of Rezult see the following chart.

bentazon
(lb ai/A)

Basagran (Product/A)

Rezult
(Product/A)

0.25

0.5 pt

0.4 pt

0.33

0.67 pt

0.56 pt

0.5

1 pt

0.8 pt

1

2 pt

1.6 pt

 

AERIAL APPLICATION OF POST CORN HERBICIDES

Rain has delayed POST application in corn in some areas. The aerial application restriction icon is listed in the weed guide for those herbicides that are not registered for the use. Callisto, Distinct, and Status are not registered for aerial application and those herbicide in the weed guide do not show that icon. We apologize for this omission.

The ND Dept of Ag and Syngenta sought temporary registration for aerial application of Callisto in corn which was done a couple of years ago. Because of EPA guidelines the temporary registration was not possible. It is doubtful that any of these three herbicides will be available for use through aerial application.

 

HERBICIDE APPLICATION TO WHEAT POST BOOT STAGE

Rain has delayed POST application in small grains without much weed control taking place. Many have called asking what will happen if herbicides are sprayed during this growth stage. A quick look on page 12 of the weed guide shows NO herbicide is labeled when wheat is in the boot stage or beyond (until preharvest). Herbicides can affect pollination, fertilization, and seed fill. Growth regulator herbicide are especially prone to cause missing or sterile florets, empty heads or head tips, and lack of seed set all of which will affect yield. Herbicide application can also cause illegal herbicide residues in wheat kernels. Uncontrolled weeds by this time have already competed with the wheat. A glyphposate preharvest application will help desiccate the weeds and facilitate harvest.

Richard Zollinger
NDSU Extension Weed Specialist
r.zollinger@ndsu.edu


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