M/k / 



COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 URBANA-CHAMPAIGN 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA, ILLINOIS 



NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



IVTE/COUNTY/LOCAL GROUPS/US. DEPARTMENT OF AGRICULTURE COOPERATING 



'OR IMMEDIATE RELEASE 



No. 15, July 10, 1970 



fh-is series of weekly bulletins provides a general look at the insect, weed, and plant 

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

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

 mine local conditions. 



INSECTS 



?ORAGE 





Grasshoppers may be scattered throughout some hay fields. Where there are 17 per 

 ;quare yard, they eat a ton of hay a day in a 40-acre field. Three to six per square 

 rard are considered enough to cause economic damage. When cutting hay, leave several 

 incut swaths as traps. Spray these with 1 pound of malathion or 3/4 pound of carbaryl 

 ^Sevin) per acre. There is no waiting period between application and harvest. 



SOYBEANS 



Grasshoppers are present throughout some soybean fields that were grass or hay fields 

 Last year. The eggs were laid in these fields then, and have now been hatching for 

 ibout two weeks. You can apply carbaryl, malathion, naled (Dibrom) , or toxaphene. If 

 grasshoppers are migrating from adjacent fields into beans, you can get the longest 

 control with toxaphene, applied as a border spray. But do not apply toxaphene next to 

 cish-bearing waters. Do not apply carbaryl near bee hives. 



Green clover worms can be found in some bean fields. They are not numerous enough now 

 to create any problem, but they do bear watching in late-planted beans. Their primary 

 lamage will be leaf eating. If they attack beans between the blossom and pod-fill 

 stages, the damage is the same as with grasshoppers. However, these worms do die of a 

 fungus infection and are found as white, dusty, mummified worms. They are also para- 

 sitized by a fly that deposits white, globular eggs on the backs of the worms behind 

 the head. These two natural enemies help control this pest. No insecticides are 

 needed at this time. 



20RN 



Grasshoppers have not been reported in cornfields. They may migrate into them later. 

 Jse the same insecticides as you would for soybeans. However, please note that diazi- 

 lon now has a label for use on corn. 



Horn rootworm adults are beginning to emerge. Although only a few western and north - 

 ern adults have been seen, more will be present soon. From now on, keep an eye on 

 silking. If there is an average of 5 or more beetles per silk and pollination is just 

 beginning, an application of carbaryl or malathion will be profitable, in order to pro- 

 tect the corn during the pollinating period. Also, check the number of rootworm bee- 

 tles, to have an idea of the rootworm prospects for that field in 1971. 



