three miles north of Junction 164 and 94 and three miles east. "Root ratings" and 

 "pull tests" will start at 1 p.m. on July 16. Worm (larval) counts will be made 

 on July 17, starting at 9 a.m. See the announcement at the end of this newsletter 

 for details. Your help at this "rootworm party" will be welcomed . Everyone will 

 get a first-hand look at 1973 control data- -and have some fun too! 



SOYBEAN INSECTS 



Thistle caterpillar damage to soybeans is rapidly declining in most areas. In gen- 

 eral, most larvae are approaching full growth, and are ready to pupate. Some have 

 already pupated. Caterpillars that are 1-1/4 to 1-1/2 inches long now are virtually 

 full-grown and do not warrant control. If damage to soybeans exceeds 30- to 40-percen 

 defoliation and the majority of larvae are less than 1-1/4 inches in length, spraying 

 with toxaphene or carbaryl will give good control. 



Leafhoppers have been observed on soybeans in the central and western areas of Illi- 

 nois. These small, green, wedge-shaped insects sometimes suck sap from the soybean 

 leaves. In general, most soybean varieties in Illinois have pubescent leaves. This 

 hair on the leaves prevents or deters feeding by leafhoppers. 



We have had plots in which smooth- leafed soybean varieties were damaged by leaf- 

 hoppers. If leafhoppers are abundant and are causing the leaves to yellow or 

 brown (die back from tip), treat with malathion at the rate of 1 pound per acre. 



Green cloverworms can be found in some soybean fields. These light-green worms 

 with white stripes running the length of their body feed on leaves, not the blos- 

 soms or pods. The green cloverworm population is still light, but the situation 

 bears watching. Control measures are not needed at this time. The damage poten- 

 tial is most critical on beans from the blossom to early fill periods. Parasites 

 and a fungus disease attack the larvae and help control them. 



FORAGE INSECTS 



Potato leafhoppers , both nymphs and adults, are numerous in some alfalfa fields. 

 They reduce hay yields as well as the quality of the hay by lowering the content 

 of Vitamin A and protein. These leafhoppers cause a yellowing of second- and 

 third-crop alfalfa. Treatment is indicated if swarms of these small (1/8- inch), 

 green, wedge-shaped insects are observed during cutting, or on the new growth of 

 the second crop. See last week's bulletin (No. 14) for recommendations. 



GENERAL INFORMATION 



Grasshoppers are abundant now in many hayfields, fence rows, ditch banks, grass 

 waterways, and similar sod areas. If the growth in these areas continues to be 

 luxuriant, many of the 'hoppers may remain there until they are mature. 



To avoid problems later, we recommend that areas where there are concentrations of 

 grasshoppers be treated now while the 'hoppers are small and easy to kill. A spray 

 of 1-1/2 pounds of toxaphene per acre can be applied to fence rows, ditch banks, grass 

 waterways, and roadsides before the 'hoppers disperse. Toxaphene is preferred if 

 weeds are blooming and attracting bees. DO NOT apply toxaphene to or near fish- 

 bearing waters. Toxaphene can be applied to corn or soybeans, but not if they are 

 used as forage. 



On hay crops, apply carbaryl (Sevin) , diazinon, malathion, or naled (Dibrom) . No 

 interval is required between the application of malathion or carbaryl and harvest. 



