-4- 



Many growers would like to put a broadleaf killer with Tref Ian for preplant incorpora- 

 tion. Limited research thus far suggests that incorporating Sencor may increase the 

 risk of soybean injury, but more detailed research information is needed in order to 

 know for sure. This practice is not registered or recommended for the 1973 season. 



In summary, we hope Sencor will help control broadleaf weeds in soybeans. But for 

 this year, if you insist on treating more than a few acres with Sencor and for any 

 reason have soybean injury, "don't call us, we'll call you." 



IF A LITTLE IS GOOD, MORE ISN'T ALWAYS BETTER 



With current soybean prices, some growers seem to be quite anxious about weed control 

 and seem willing to spend more than usual. Remember that increasing the rate of ap- 

 plication above the recommended maximum does not necessarily mean that the result will 

 be improved weed control or broader spectrum control ; but doing so may cause soybean 

 injury. In working to control weeds, don't use excessive rates, because that could 

 mean excessive soybean injury. 



AMIBEN RATES 



One of the best places to improve performance is to use the full, recommended rate of 

 Amiben. Many growers have been using 2 pounds of active ingredient per acre. The full 

 rate recommended is 3 pounds. That is 1-1/2 gallons of liquid (2 pounds per gallon), 

 or 30 pounds of 10G on a broadcast basis (proportionately less in a band) . 



TREF LAN FOLLOWED BY AMIBEN 



There is increasing interest in using Amiben banded following a Tref Ian preplant in- 

 corporated application. The label states, "Band applications of Amiben may be made 

 for broadleaf weed control over the top of preplant soil incorporated grass killers." 

 Although this would appear to allow use following preplant applications of Lasso, Ver- 

 nam, or Cobex, most of the research and field experience has been with Amiben follow- 

 ing Tref Ian. 



Since either Amiben or Tref Ian alone may sometimes cause soybean injury, the dual ap- 

 plication would seem to increase the possibility of injury. However, thus far, injury 

 from the dual application has not been a major problem in our research trials or in 

 limited field use. Even so, this does not eliminate the possibility of a problem. 



If you are using maximum herbicide rates- -alone, in combinations, or in sequential ap- 

 plications, be sure to use one of the more vigorous soybean varieties. 



INCORPORATING TREF LAN 



Treflan has been applied to some fields that were in corn last year but not plowed in 

 the fall or spring. The question would be, "Was disking adequate to incorporate the 

 Treflan?" This depends on many factors, such as the condition of the soil when disked, 

 the amount of crop residue present, and the type of equipment used. If the disk or 

 other tillage tool gave relatively good mixing action, the Treflan may be adequately 

 incorporated- -but perhaps not quite as good as if the field had been plowed. You'll 

 soon know the results as the weeds begin to grow. 



SPRAYING WEEDS BEFORE TILLAGE 



Weeds sometimes grow before tillage is possible to prepare the seedbed for soybeans. 

 When this happens, should a herbicide be applied before the field is worked? Today's 



