-5- 



WEEDS 

 FIELD WEED CONTROL 



Corn. If you did not get your herbicide on at planting time, you may still have 

 some flexibility. Ramrod or Ramrod- atrazine can be applied until grass weeds are 

 in the two- leaf stage. Corn that is up has enough tolerance to Ramrod and atrazine, 

 so let weed size be your guide. Atrazine and oil can be used until the weeds are 

 1-1/2 inches tall. But there has been occasional corn injury with atrazine and 

 oil- -especially under wet, cool stress conditions. Do not add 2,4-D or Banvel to 

 atrazine and oil, because of the increased risk of corn injury. Another "no no" 

 is Lasso after corn emergence. 



If you used Sutan and if some grasses have started to emerge, do not get excited 

 prematurely. They will probably curl and die. With atrazine, too, some weeds may 

 emerge and then die. You need not spend too much time trying to "start them down." 

 The rotary hoe will usually do much more good than harm, even if a herbicide has 

 been used for corn or beans . 



One of the major weaknesses of using Ramrod- atrazine is often the lack of velvet- 

 leaf control. If velvetleaf gets started, use good cultivation and/or 2,4-D as 

 an early postemergence treatment. 



If the weather should turn wet and cool, avoid spraying 2,4-D on corn under stress 

 conditions . 



Smartweed . It is prevalent in many areas again. A lot of folks have asked about 

 spraying this weed with 2,4-D or Banvel before working the seedbed. Smartweed 

 is not easily controlled with 2,4-D. If you are considering Banvel, be certain 

 there are no susceptible plants in the area. Modern tillage equipment should give 

 a weed- free seedbed in most fields. And atrazine applied almost any approved way-- 

 alone or in combination, surface or incorporated, pre- or postemergence- -usually 

 can be counted on for good smartweed control. 



If you expect to have smartweed problems in soybeans, kill any existing weeds with 

 good seedbed preparation. And remember the value of Chloro IPC- -used at 2 to 5 

 pounds per acre active on a broadcast basis, or proportionately less in a band. 

 It comes as a 4-pound-per-gallon EC, or as granules. Apply it to the surface. Do 

 not incorporate. Chloro IPC can be used alone or following previously incorporated 

 Treflan. Some of the other Chloro IPC combination treatments are being tested 

 more extensively this year. 



Do not use Banvel on smartweed where you plan to plant soybeans. The use of 2,4-D 

 on smartweed before soybean planting may or may not give good results. The 2,4-D 

 may or may not affect soybeans, depending on the rate and formulation, rainfall, 

 soil moisture, temperature, and the interval between application and planting. 



Soybeans . Since some corn herbicide applications were delayed because of rain, 

 soybean herbicides need to be on before or at planting time. If this is not done, 

 we do not have many alternative postemergence herbicides to suggest for soybeans. 

 Dinitro is only for very early postemergence use. Tenoran can be used on broad- 

 leaved weeds up to 2 inches tall, and may help some on small grass. Tenoran may 

 have some noticeable effects on beans, but damage to them usually is not severe. 

 2,4-DB is a possibility a little later. Although these postemergence treatments 

 for soybeans may be helpful in certain situations, none of them have had much 

 acceptance in Illinois. 



