per 25 gallons of spray mixture. Cover the weeds with the spray, but keep it off 

 the corn as much as possible. 



Evik 80W (ametryne) is cleared for directed use when the corn is more than 12 inches 

 tall and when the weeds are less than 4 inches tall. Use 2 to 2-1/2 pounds of Evik 

 80W per acre (broadcast basis). Add a surfactant (such as X-77, WK, or Tronic) at the 

 rate of 2 quarts per 100 gallons of spray mixture (0.5-percent of the spray volume). 



Dowpon (dalapon) may be applied as a directed spray when the corn is 8 to 20 inches 

 tall from the ground to the whorl. Use "leaf lifters" to keep Dowpon off the corn 

 plant. Direct the .spray into the row, and do not let the spray contact more than the 

 lower half of the stalk or more than 7 inches (whichever is greater) . Use 2 pounds of 

 Dowpon or Dowpon M (not Dowpon C) on a broadcast basis. You can add 2,4-D to control 

 broadleaf weeds. Basfapon is another trade name for dalapon, and it may be used in a 

 similar manner. 



Adjust the rates of all these herbicides for directed bands if you do not broadcast 

 the spray between the rows. Refer to the labels for other precautions. Consider these 

 only as emergency treatments . 



HERBICIDE INJURY 



Sutan injury to corn has been the topic of several calls received this week. The cool 

 soil temperatures of previous weeks combined with the high temperatures last week are 

 probably a contributing cause to the lateness of the injury symptoms. Corn hybrids vary 

 in their susceptibility to Sutan injury, but climate is also a factor. Sutan injury 

 synptoms are twisted, malformed leaves that may appear to be "onion leafed," or show 

 a laddering effect as the result of the leaf tips failing to unfold normally. Grass 

 weed seedlings are likely to show the same effect if not controlled earlier. If the 

 leaves are not rolled too tightly, the corn will probably break through and recover. 



BROADLEAF WEEDS IN CORN 



2,4-D and Banvel (dacamba) are the two top choices for broadleaf weed control in corn. 

 2,4-D will control most annual broadleaf weeds effectively and economically. Use "drop 

 pipes" or nozzle extensions from the boom to keep the spray out of the corn whorl, if 

 the corn is more than 8 inches tall. Do not spray with 2,4-D after the corn begins to 

 tassel. 



The rate of 2,4-D to apply depends on the strength of the concentrate and the type of 

 2,4-D used- -amine or ester. If you use the amine form, apply 1 pint of a 4-pound-per- 

 gallon formulation. If you use the ester form, use 1/2 pint or less of the 4-pound- 

 per-gallon formulation. The amine form is less likely to cause drift problems, but 

 most farmers consider the ester form as more active and less likely to wash off with 

 a rain. Weeds are easier to kill when they are small, so adjust the rate to the weed 

 size. 



Each year 2,4-D damages some corn. The symptoms are an elbowing of the stalk, abnormal 

 brace roots, and "onion leafing." Corn seems most susceptible to 2,4-D damage when it 

 is under cool, wet-weather stress or when it is growing fast during hot, humid periods. 

 Adjust the rates for directed, band sprays. Corn stalks are often brittle for seven to 

 ten days after spraying with 2,4-D, so delay cultivation if possible. 



Banvel is cleared for use on corn until the corn is 36 inches high or until ten days 

 belore the tassels emerge. Banvel is similar to 2,4-D, but it provides more effective 

 control of smartweed and Canada thistle. Banvel drift often affects soybeans near 

 treated corn fields , causing a cupping of the soybean leaflets about two weeks after 



