Roller pumps- -or any pump for that matter- -should not be operated dry. Excessive heat wil 

 damage the rollers and seals. With a clear suction line and an open discharge line, the 

 pump should displace liquid within 15 seconds. When used for spraying wettable powders, 

 roller pumps should not be shut off as long as the wettable powder suspension is in the 

 pump housing. If the pump is shut off, the wettable powder will settle to the bottom of 

 the pump and will cause damage when the pump is started up again. 



The water used should be free of suspended solids that can cause wear. Use only clean 

 water that is filtered while filling the tank. 



The centrifugal pump is rapidly gaining in popularity, and it is recommended over the 

 roller pump for handling wettable powders. A centrifugal pump made of abrasion-resistant 

 materials will pump wettable powder suspensions satisfactorily. Its capacity is high, so 

 keeping wettable powders in suspension should not be a problem if an adequate bypass syste 

 is used. It is readily available for tractor-PTO use at a reasonable price. But the 

 centrifugal pump is more expensive than the roller pump. The main limitation of the cen- 

 trifugal pump is its maximum pressure. However, such pumps are entirely adequate for 

 field applications of herbicides, liquid fertilizers, and most insecticides. 



The piston pump , if properly constructed, will handle wettable powders satisfactorily. 11 

 provides far more pressure than is needed for most field spraying but the increased pressii 

 may be necessary for fungicide applications. 



SPECIAL ANNOUNCEMENTS 



Pesticide Dealers and Applicators Field Days/1: 30 p.m. each day 



April 15, Office of the Monroe County Extension Adviser, Arlin Obst, Waterloo. 

 April 16, Office of the Madison County Extension Adviser, Warren Bundy, Edwardsville . 

 April 22, Office of the Greene County Extension Adviser, Eldon Starkweather, Carrollton. 

 April 23, Office of the Macon County Extension Adviser, Warren Myers, Decatur. 



Insect and plant disease trouble -shooting will be the general topic with special emphasis 1 

 on alfalfa weevil and corn borer. 



READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 



INSECTS: H.B. Petty, Steve Moore, Rosooe Randell, Don Kuhlman, and Stephen Sturgeon, 

 University of Illinois College of Agriculture, Urbana-Champaign and Illinois Natural His- 

 tory Survey. 



PLANT DISEASES: M.C. Shurtleff and M.P. Britton, Department of Plant Pathology. 



WEEDS: Marshal McGlamery and Ellery Knake , Department of Agronomy; J.D. Butler, Departmev 

 of Hortioulture . 



AG ENGINEERING: John Siemens. 



AG COMMUNICATIONS: Del Dahl. 



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

 sion advisers, and others, in cooperation with the USDA Agricultural Research Service, 

 Plant Pest Control Branch. 



