COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 URBANA-CHAMPAIGN 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA, ILLINOIS 



NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



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



AUG 



- nig 



•aasaa 



No. 15, July 14, 1972 



FOR IMMEDIATE RELEASE 



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 



GENERAL INSECTS 



Grasshoppers have hatched and are very numerous in many fence rows, roadsides, and 

 ditch banks , as well as in alfalfa, clover, and other hay fields. Hard, beating 

 rains will kill newly hatched grasshoppers, but will not kill them after they are a 

 few days old. Although some of the overwintering eggs may have hatched during the 

 recent rains and some tiny grasshoppers may have been killed, the hatch continues. 

 The grasshoppers that hatched more recently may survive. 



You may find these tiny grasshoppers all over where soybeans or com was planted on 

 hay-crop ground. Or, you may find them in this year's hay crop since the eggs were 

 layed in it last fall. Of course, the tiny differential grasshoppers can still be 

 found in fence rows and ditch banks. If these tiny grasshoppers are very numerous, 

 as they are now in many areas, it will be easier to control them at this stage while 

 they are small than it will be later. 



In fence rows, apply carbaryl (Sevin) , diazinon, malathion, naled (Dibrom) , or toxa- 

 phene. In hay fields, use the same materials except for toxaphene. Cut the hay and 

 drive the grasshoppers into an occasional uncut swath. Then, spray it. Carbaryl and 

 malathion at 1 pound per acre require no waiting period after application; naled re- 

 quires 4 days; diazinon, 7 days. 



Provide protection around the edges. Grasshoppers do migrate into soybeans. If the 

 migration is prolonged, you may have to spray the borders several times. Always read 

 the label for more-detailed restrictions. 



CORN INSECTS 



Corn leaf aphids began to appear in many corn fields across the state this week. ^ 

 They migrated into these fields as dark-colored, winged adult aphids. Winged aphids 

 usually crawl down into the whorls of the corn plant and begin giving birth to their 

 young. In general, most colonies in the whorls will have very few aphids at present. 

 But the percentage of plants with one or more aphids ranges from 10 to 50 in much of 

 the state with occasional fields in north-central Illinois going as high as 80 to 90 

 percent . 



Fields of corn in early or full tassel will escape the buildup in the aphid popula- 

 tion. But in most regions of the state, the wide range in corn-planting dates means 



