COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 URBANA-CHAMPAIGN 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA, ILLINOIS 



MSEC! WEED & PLANT DISEASE SURVEY BULLETIN 



WE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



AUG 



FOR IMMEDIATE RELEASE 



19t£ 



No. 13, June 30, 1972 



This series of weekly bulletins provides a general look, at the insect , weed, and plant 

 disease situation (fruit and commercial vegetables excepted) , along with suggested, 

 abbreviated, control measures. Each individual should check his own fields to deter- 

 mine local conditions. 



INSECTS 



CORN INSECTS 



European corn borers are still not abundant in corn fields. Perhaps the moths were 

 killed by winds and rains before they deposited their eggs, or they may have layed 

 their eggs and the larvae may have died before the corn crop was mature enough for 

 them to survive. There is always the fear that a small percentage of the corn-borer - 

 moth population may "hang around" long enough to create a problem in a few of the 

 most mature fields. 



Check such fields on the west side of the state, particularly those in the northern 

 third of that area. If severe infestations show up, apply carbaryl or diazinon gran- 

 ules. 



Corn flea beetles can now be found in many corn fields in the southern half of Illi- 

 nois"] We have had evidence for some years that there may be two generations of this 

 pest each year. The beetles overwinter, emerge, feed, and deposit their eggs. The 

 larvae that hatch from these eggs mature into adults by late June and early July. 

 Another generation may develop by mid-August. However, prolonged egg- laying by the 

 overwintering beetles may result in an extended emergence of beetles from early July 

 through August, and only one generation a year. 



Regardless, we are unable to recommend a control. Since these beetles transmit the 

 bacteria that cause Stewart's disease, we fear that it may be worse as a leaf infec- 

 tion this year than during the past few years. 



SUNFLOWER INSECTS 



Plant bugs have been observed on sunflowers this week. These are small, green bugs 

 that move rapidly over the plant and suck sap from the leaves and stems. We do not 

 know whether or not they are feeding on the forming heads. 



Aphids are also small and green, but move very slowly in a lumbering manner. They 



also suck sap from the plant, excreting a sticky material called honey dew. This 



material is quite common. It often serves to identify an aphid infestation. The 

 populations of these two pests have been low, and no control is recommended. 



