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AGRONOMY FACT SHEETS COVER WEED-CONTROL PROBLEMS 



Weed control in forages , small grains , and sorghum are covered in Agronomy Fact 

 Sheets W-25, W-26, and W-27, respectively. If you need copies, ask your county 

 Extension Adviser or write the Agronomy Department, University of Illinois at 

 Urbana- Champaign, Urbana, Illinois 61801. 



PLANT DISEASES 



POSITIVE AND CORRECT IDENTIFICATION NEEDED 



Positive and correct diagnosis is necessary before any attempt is made to develop 

 and initiate control methods and procedures for plant diseases. These may 

 be caused by several kinds of parasitic organisms (pathogens) , or by abiotic (non- 

 living) elements in the environment that adversely affect plant growth. Thus, it 

 is important to know what the problem is before any control practices are initiated. 



A disease in plants can be recognized by comparing the symptoms that appear on dis- 

 eased plants with the appearance of healthy plants. In many cases , however, a special 

 laboratory examination is required to isolate and identify the pathogen or causal 

 agent . 



If you have a specimen from a diseased plant that you want diagnosed, start with the 

 county Extension Adviser in your area. If necessary, he will forward the sample to 

 a specialist at the University of Illinois, Urbana- Champaign. 



Whether you send in a sample yourself or have an Extension Adviser do it for you, 

 include enough information to help the specialist make a rapid and accurate diagnosis. 

 This is an important part of making the process work properly. 



Extension Advisers have copies of "Instructions and a Check List for Plant Disease 

 Diagnosis" to use when submitting a sample. That sheet includes the following tips: 



1. Be sure the sample is representative of the injury or disease. 



2. If more than one type of problem exists, send separate samples for each. 



3. Press dry leaves- -healthy and diseased, for comparison- -and stems and branches 

 between sheets of either dry paper toweling, wax paper, aluminum foil, or card- 

 board. 



4. When sending a whole plant, wrap the roots only with the adhering soil in a 

 plastic bag. 



5. Do not send fruit in an advanced state of decay. Wrap the fruit individually, 

 and mail as quickly as possible. 



6. Do not add water or crush specimens unnecessarily. 



7. Place the specimen in a sturdy envelope or mailing box and send: 



• shade tree and shrub problems to: Dr. J.C. Carter 



385 Natural Resources Building 

 Urbana, Illinois 61801 



