-4- 



in the soil injure soybeans? (2) Is there a legal tolerance set for any herbicide 

 that may be in the soybeans at harvest? 



If you used AAtrex (atrazine) alone or in combination with another herbicide for 

 corn, do not replant to soybeans. The risk of atrazine injury to soybeans is high. 

 Sorghum has tolerance to atrazine, Ramrod, and Lorox--but not to Sutan, Eptam, or 

 Lasso. 



Sutan- -if used for corn weed control --could also cause injury if soybeans are planted 

 too soon. The manufacturer says, "If it is too late to plant corn again, soybeans 

 may be planted providing no atrazine was used with the Sutan. Do not plant soybeans 

 sooner than 21 days after application of Sutan." 



Lasso is approved for both corn and soybeans , so there is no problem if you replant 

 soybeans in fields where Lasso alone was used for earlier corn-weed control. Ramrod 

 is cleared for corn and seed soybeans , but that means only for soybeans to be used 

 for replanting and not for food, feed, or oil uses. 



Lorox and Bromex are cleared for corn and soybeans , but few people use Lorox or Bro- 

 mex alone on corn. Some use Lasso in combination with Lorox or Bromex because there 

 is no problem if it is necessary to replant to soybeans. 



HERBICIDES FOR DOUBLE-CROPPING 



Double -cropping soybeans immediately following early wheat harvest looks like a good 

 bet for many farmers. If you have a no-till planter planting directly in wheat stub- 

 ble has the advantage of conserving moisture and time. 



Lorox (linuron) plus a surfactant may control small weeds that have emerged in the 

 wheat stubble. If weeds are too large for adequate postemergence control with Lorox, 

 you will need to use 1 to 2 pints of Paraquat to knock down existing weeds. Adjust 

 the rates of Lorox to the organic -matter content of the soil, but 1-1/2 to 2 pounds 

 of Lorox 50W are the usual rates. If annual grasses appear to be a serious problem, 

 consider adding 1 to 2 quarts of Lasso and reducing the rate of Lorox. For postemer- 

 gence knockdown of weeds , use plenty of water for good coverage (30 to 50 gallons per 

 acre) and add a suitable surfactant. 



Grain sorghum is also sometimes double- cropped after wheat . AAtrex (atrazine) as an 

 early postemergence treatment may control the weeds but if weeds are more than 1-1/2 

 to 2 inches tall, it is better to use Paraquat at planting. 



DIRECTED POSTEMERGENCE APPLICATIONS FOR CORN 



Directed sprays are sometimes considered for emergency weed control in corn when grass 

 weeds become too tall to control with cultivation. However, weeds are often too large 

 for directed sprays to be very practical by the time help is sought. Directed sprays 

 cannot be used on small corn, and a height difference between corn and weeds is needed 

 in order to keep the spray off the corn. Directed nozzles can be attached to the boom 

 with rigid pipes, on skids or gauge wheels, or on cultivator shanks. The main precau- 

 tion is to minimize the spray contact with the corn foliage. 



Lorox 50W (linuron) can be applied as a directed spray after the corn is at least 15 

 inches high, but before the weeds are 8 inches tall. Use 1-1/4 to 3 pounds of Lorox 

 50W (broadcast basis). Use the lower rates on small weeds, lighter soil types, and 

 soils that are low in organic -matter content. Add Surfactant WK at the rate of 1 pint 



