The seedling or "new grass" treatment is a vital part of any Johnsongrass control program. 

 The seedlings are controlled by a preemergence herbicide. We suggest using Sutan in corn- 

 Treflan, Planavin, or Vernam in soybeans. 



HERBICIDE INCORPORATION 



Most annual weed seeds germinate in the top 2 inches of the soil and the herbicide is 

 usually needed here for the best results. Incorporation prevents surface losses of vola- 

 tile herbicides and moves low-solubility herbicides into the soil. Most herbicides of 

 moderate solubility move into this weed seed zone with normal rainfall. 



To incorporate herbicides, use a tandem disk-harrow or a rotary tiller. With powered 

 rotary tillers, the distribution of the herbicide is best when the increment of cut is 

 2 inches and when many knives are used as possible--at high rotor speeds or slow ground 

 speeds. However, powered rotary tillers are not available on most farms and they do not 

 always leave the most-desirable seedbed. The tandem disk is the tool most commonly used 

 for herbicide incorporation. The disk does not incorporate as uniformily as the rotary 

 tiller. And it has a tendency to partially invert a soil slice, concentrating the pesti- 

 cide along a diagonal plane parallel to the direction of travel. A single disking results 

 in zones of high concentration. In tests by the Agricultural Engineering Department, an 

 additional disking did not increase the uniformity of incorporation much. 



Studies of the effects of travel speed and gang angle show that the distribution can be im- 

 proved when gang angle is increased and the tandem disk is used at high, but safe, speeds. 

 The soil should be loose and not too moist for best results. A wet, sticky soil resists 

 incorporation. 



The tandem disk should be operated at a depth of about 4 inches for best results. Greater 

 depths may cause excessive dilution of the herbicide. 



Field cultivators, chisel plows, and spring-tooth harrows are not satisfactory because they 

 primarily just shatter and lift the soil. They cause the finer particles to be moved down- 

 ward, leaving the clods on top and little mixing occurs. 



PLANT DISEASES 



WHEAT DISEASES 



Septoria leaf blotch is abundant now on the lower leaves of plants in nearly all Illinois 

 fields. The disease has spread upward to new leaves during the last week throughout the 

 southern one-half of Illinois. 



In Gage wheat, septoria is especially severe in combination with infection by soil-borne 

 wheat mosaic virus . The .symptoms of the combined diseases are apparent as irregular areas 

 of yellowed wheat. Individual leaves are mottled from the virus infection. The septoria 

 infection produces a streaking. 



Recovery from the virus symptoms will occur in two to three weeks. But septoria infection 

 may remain heavy throughout the rest of the growing season. 



Powdery mildew may appear anytime on wheat and winter barley in southern Illinois where the 

 crop is dense and fertility- -especially nitrogen- -is high. Mildew has become an increas- 

 ingly important disease in recent years as farmers have increased the use of fertilizers 

 and rate of seeding. High nitrogen produces a rank, dense growth that creates an ideal 



