The use of adjuvants with Fusion plus Basagran plus Reflex or with Twister did not improve weed control in this study, likely because excellent soil moisture and temperature promoted excellent control with these herbicides without an adjuvant. Soybean yield ranged from 2 bu/A in the nontreated plots to 49 bu/A.

I. INTRODUCTION:

This study was designed to evaluate several adjuvants from Wilfarm L.L.C. and the 'novel' adjuvant Scythe from Mycogen. These adjuvants were evaluated with several POST grass and broadleaf herbicides, Scythe presumably is an adjuvant at low concentrations and presumably controls weeds alone at a high concentration.

II. HERBICIDES AND ADJUVANTS EVALUATED:

        HERBICIDES               WILFARM ADJUVANTS               MYCOGEN
        ADJUVANTS
        Basagran 4 EC            Crop Oil Plus                   Scythe 
        Fusion 2.66 EC           Eth-N-Ate                       Other Adjuvants
        Raptor 1 AS              Eth-N-Gard                      28% UAN
        Reflex 2 EC              Hasten                          Prime Oil COC
        Twister 1.82 ME          Slygard 309                     Sun-IT II

III. ABBREVIATIONS USED:

        ABONOR: above normal                        LVS: leaves
        ABUTH: velvetleaf                           SETFA: giant foxtail
        BROFOL: broadcast foliar                    V: vegetative stage
        CYPES: yellow nutsedge                      W: weeds
        GLXMA: soybeans                             XANST: common cocklebur
        IPOHE: ivyleaf morningglory                 ZEAMX: corn

IV. RESULTS AND DISCUSSION:

Weed control ratings and soybean injury and yield data are presented in the attached table. There was no change in weed control following the July 12 rating. Yellow nutsedge was not rated because of nonuniformity in the plot area.

Weed Control:

Soil moisture was excellent at the time of herbicide application and temperatures were optimum for herbicide absorption and translocation, apparently because of these growing conditions, Fusion plus Basagran plus Reflex without any adjuvant controlled giant foxtail 99%, velvetleaf 96%, ivyleaf morningglory 98%, and cocklebur 91%. There was no increase in weed control with these herbicides when any of the adjuvants were used with the herbicides. Likewise, weed control with Twister did not increase when an adjuvant was used with it.

Soybean Injury and Yield:

All treatments caused 15% soybean injury but recovery was rapid and complete. Soybean yield ranged from 2 bu/A in the nontreated plots to 49 bu/A. 

The Site Description Sheet lists pertinent information such as planting and application dates, weed species present, and soil characteristics.

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Evaluation of Weed Control in Soybeans with Pursuit with ICI Adjuvants, 1996.

The several ICI adjuvants evaluated improved giant foxtail control with Pursuit, especially at the 4 oz/A rate. However, maximum control observed was only 68%. The ICI adjuvants did not influence control of yellow nutsedge, common ragweed, or velvetleaf in this study. Little or no soybean injury was observed. Soybean yield ranged form 11 bu/A in the nontreated plots to 35 bu/A.

I. INTRODUCTION:

Postemergence herbicides are applied on approximately 60% of the U.S. soybean acreage. Almost without exception, one or more adjuvants are used with each application, thus the adjuvant market has become substantial in the last decade. This study was designed to evaluate several ICI brand adjuvants for their efficacy wit Pursuit.

II. HERBICIDES EVALUATED:

        Pursuit 70 WG

III. ADJUVANTS EVALUATED:

        AL-2857 (COC)
        Atplus 411 F (COC)
        Atplus 467 (COC)
        Atplus S-12 (NIS)
        Atplus S-14 (NIS)
        Scythe (from Mycogen)

IV. ABBREVIATIONS USED:

        ABONOR: above normal                        IPOHE: ivyleaf morningglory
        ABUTH: velvetleaf                           LVS: leaves
        AMARE: redroot pigweed                      POLPY: Pa. smartweed
        AMATA: common waterhemp                     SETFA: giant foxtail
        AMBEL: common ragweed                       V: vegetative stage
        AMBTR: giant ragweed                        W: weeds
        BROFOL: broadcast foliar                    XANST: common cocklebur
        CYPES: yellow nutsedge                      ZEAMX: corn
        GLXMA: soybeans

V. RESULTS AND DISCUSSION:

Weed control ratings and soybean injury and yield data are presented in the attached table. There was no change in weed control following the Aug. 14 rating. Several weed species listed on the Site Description Sheet were not rated because their distribution was not uniform in the plot area.

 Weed Control:

Pursuit at 2 and 4 oz/A without an adjuvant controlled giant foxtail 8 and 20%, respectively. This low level of control with Pursuit occurs frequently at this location, even when adjuvants are used. The addition of the several ICI adjuvants improved foxtail control in most instances, but maximum control observed was only 68%. Pursuit at 4 oz/A with adjuvant consistently controlled more foxtail than at the 2 oz/A rate. The higher concentration of the several adjuvants with Pursuit controlled foxtail better than the lower adjuvant concentration. There was no great difference between the several adjuvants evaluated with Pursuit regarding grass control.

Pursuit did not control any yellow nutsedge regardless of adjuvant used. Control of common ragweed and velvetleaf with Pursuit was not different whether an adjuvant was used or not and with no difference between Pursuit rates.

Soybean Injury and Yield:

There was little or no soybean injury observed in this study. Soybean yield ranged fro 11 bu/A in the nontreated plots to 35 bu/A. The incomplete control of several weeds in this study likely reduced yield. 

The Site Description Sheet lists pertinent information such as planting and application dates, weed species present, and soil characteristics.

Treatment Lists and Data Tables will require the Adobe Acrobat and WebLink (TM) plug-ins.

The best way to look at our Treatment Lists and Data Tables is to print them using your laser printer.

If you are unable to access our Data Tables using Adobe Acrobat and your laser printer .

Go to the Weed Control Progress Reports Homepage .

Go to the Plant and Soil Science Department Homepage .

Go to the Southern Illinois University at Carbondale Homepage .