-7- 



label says to apply in 20 to 40 gallons of water per acre. Application in less water 

 than that stated on the label for ground equipment could be interpreted as an unlabeled 

 use of the herbicide. Also, many of our postemergence herbicides are not labeled for 

 use over the top of crop plants and must be applied as directed sprays to the base of 

 crop plants. This cannot be done with a span sprayer. Another problem is the poten- 

 tial danger to the operator. The person running a span sprayer is more exposed to the 

 fine-spray particles of concentrated pesticides. The operator must wear protective 

 clothing and a respirator, to prevent skin contact and breathing toxic pesticides. 



F oam and air-induction nozzle systems have been developed recently. Researchers have 

 measured drift, using available foam adjuvants with air-induction nozzles. Drift was 

 compared for dyed spray solutions (with and without foam adjuvants) , using several dif- 

 ferent types and sizes of air-induction nozzles and three sizes of conventional flat- 

 fan nozzles. The large droplets produced by the air- induction nozzles (with and with- 

 out a foam adjuvant) resulted in significantly less drift than sprays from the conven- 

 tional flat- fan nozzles. 



Large droplets are produced by the air- induction nozzles because of the low pressure 

 at the second orifice. Because of that, a less-desirable distribution pattern would 

 be expected with these nozzles than with regular, flat-fan or flooding-type nozzles 

 operating at recommended pressures . 



Whirl chamber nozzles have been available in Illinois for several years. These pro- 

 vide a hollow- cone spray pattern that gives poor distribution when mounted on a boom 

 for broadcast application. Whirl chamber nozzles are primarily used in front of a 

 disk or other incorporating tool when applying herbicides. 



This nozzle should be tilted forward or backward about 30 degrees to obtain uniform 

 coverage. Our concern with this arrangement is the potential for excessive drift and 

 distortion of the spray pattern, especially in windy conditions. 



Among nozzles of the same capacity and that are operated at the same pressure, the 

 whirl-chamber nozzle produces smaller droplets than the flat-fan or the flooding-type 

 nozzle. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows : 



INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman, and Tim Cooley , College 

 of Agriculture, University of Illinois at Urbana-Champaign , and the Illinois Natural 

 History Survey. 



WEEDS: Ellery Knake and Marshal McGlamery , Department of Agronomy , and A.J. Turgeon , 

 Department of Horticulture. 



PLANT DISEASES: M.C. Shurtleff , Ed Burns, and Tim Bowyer , Department of Plant Pathol- 

 ogy. 



AG COMMUNICATIONS: Ray Wood is . 



AG ENGINEERING: John C. Siemens. 



The information for this report was gathered by these people, staff members, county Ex- 

 tension advisers, and others, in cooperation with the USDA Animal and Plant Health In- 

 spection Service. 



