PLANT DISEASES 



SOUTHERN CORN LEAF BLIGHT 



Dry weather during the past week appears to have slowed the development and spread of 

 southern com leaf blight in Illinois. However, varying amounts of rainfall during 

 the Fourth of July weekend plus generally hot and humid conditions in many areas will 

 increase the favorable conditions for this disease. 



If favorable weather conditions prevail, a new wave of blight infections could show 

 up during the next three to seven days. Cloudy conditions could speed-up development, 

 which is slower under bright and sunny conditions. Keep a close watch for blight de- 

 velopment in susceptible corn fields, especially in areas that received rain. 



In most cases, the blight has not spread from the lower leaves to upper leaves so far. 

 Blight symptoms that appear on the upper leaves only indicate that the infection is 

 spreading from one field to another. 



Reports from Florida, Alabama, and Georgia indicate that blight incidence in those 

 states is still of "no economic importance." About 90 percent of the corn planted 

 there is normal cytoplasm, and the weather has been dry. 



Some corn producers in at least eight Illinois counties are spraying to protect their 

 crops against the southern corn leaf blight. It will be three weeks before we will 

 be able to measure the effectiveness of this effort. 



SPECIAL MEETING ANNOUNCEMENTS 



CORN ROOTWORM-INSECTICIDE DEMONSTRATION PLOTS 



We will examine the roots and count the number of worms per plant, for different in- 

 secticides applied at planting time. This will give you a chance to see the results 

 of the various insecticide applications side by side in the same field. 



We invite you to a "rootworm party" to make counts and evaluate the different insec- 

 ticides. (Bring a pocketknif e . ) If you cannot be there at 9:00 a.m. when they start, 

 come later. The counts will be completed by mid -afternoon. 



July 12 Boone County. 



July 13 McHenry County. 



.Clyde Curtis farm, 1 mile north of the 

 junction of Routes 173 and 76, and 1 

 mile west of Route 76 on the north side 

 of the road. Wally Reynolds, Extension 

 Adviser, Belvidere. 

 Phone: (815) 544-3710. 



.Robert Stoxen farm (9106 Lawrence Road, 

 Harvard, Illinois) 

 Phone: (815) 943-5934 

 Go 1-1/4 miles north of Lawrence, Illinc; 

 (Lawrence is 2 miles northwest of Harvar. 

 Louis M. Engelbrecht, Extension Adviser, 

 Woodstock. Phone: (815) 338-3737. 



