-5- 



Dalapon can be used as a directed spray for corn that is eight to twenty inches tall. 



Lorox can be used as a directed spray after corn is at least fifteen inches high. Di- 

 rected sprays require special equipment and very careful application to avoid corn 

 injury. This practice has not been popular in Illinois. If interested, check the 

 1972 Weed Control Guide and product labels for further information. 



We do not have a good answer to the problem of postemergence control of grass weeds 

 in corn. Preplant or preemergence treatments and good cultivation are still the ma- 

 jor ways of controlling grass weeds in corn. 



POSTEMERGENCE HERBICIDES FOR SOYBEANS 



Tenoran can be used postemergence in soybeans from the time trifoliate leaves form 

 until broadleaf weeds are two inches tall. For best control, velvetleaf should not 

 be more than an inch high. Do not expect to control grass weeds that are more than 

 half an inch tall. You can expect soybeans to show some effects from the Tenoran 

 treatment . 



2,4-D may be applied as a directed spray after soybeans are at least eight inches 

 high and if the weeds to be controlled are only about three inches high. The spray 

 should not contact more than the bottom third of the soybean plants , and should not 

 contact the growing terminals. Special equipment should be used for directing the 

 spray. If cocklebur forms a canopy over soybeans, 2,4-D may be broadcast once from 

 ten days before bloom to mi db loom- -when the soybeans are about knee-high. 



Soybeans treated with 2,4-D may have a wilted appearance soon after treating and may 

 show increased stem cracking and lodging. Where cockleburs are serious, the advan- 

 tages may outweigh the disadvantages. 2,4-DB can also give some control of giant 

 ragweed and annual morning-glory. Spray only where these weeds are actually present 

 in the field. 



Dyanap is used in some of the southern states where soybeans are grown. It is la- 

 beled for use after soybeans are planted, but before emergence. Dyanap is a mixture 

 of dinoseb (dinitro) and naptalam (Alanap) . We have had several questions about it, 

 but it has not been a popular treatment in Illinois. 



Dynoram is a relatively new combination of dinitro and Amiben for use preemergence 

 or from cracking to very early postemergence. 



Dinitro can be used as an early postemergence treatment when soybeans have emerged 

 and are still in the cotyledon stage, before the first leaves open to expose the 

 terminal bud. Dinitro may also be used as a directed postemergence treatment to 

 control some broadleaf weeds such as cocklebur and morning-glory when soybeans are 

 five inches high up to the time they begin to bloom. Special, directed spray equip- 

 ment is needed to minimize contact with the soybeans. 



Although dinitro and some combinations containing dinitro have been fairly popular 

 in some southern states, they have not been used extensively in Illinois. Here are 

 some of the reasons: Cocklebur is one of the major weed problems in some southern 

 areas, and control is one of the major reasons for using dinitro. In some of these 

 areas, such as the Mississippi delta, cotton and soybeans are grown, but very little 

 corn. Therefore, Southern growers are not able to use atrazine and 2,4-D as we do 

 in the Midwest. Many Southern growers have also had more experience with directed 

 sprays , have appropriate equipment , and perhaps have more labor available for the 

 extra trips over the fields. 



