Thrips are abundant in the whorl leaves of corn. A few fields have been reported 

 as being damaged by this insect. They are black or yellow insects about 1/16- inch 

 long. Their rasping-sucking mouth parts leave tiny white streaks on the leaves. 

 If moisture is ample, damage does not usually become severe. If plants are being 

 seriously injured, carbaryl (Sevin) at 1 pound per acre will provide control. 



Common stalk borers have been tunneling in the whorl leaves of occasional corn 

 plants . These striped borers are whitish-brown with a distinct purple-to-black 

 band around the middle of their bodies. The unfolding leaves of corn have ir- 

 regular holes from feeding. Damage occurs in plants along fence rows, ditchbanks , 

 and grass waterways or where there was a weed problem the previous year. Injury 

 is of little consequence; by the time the worms are found, it is too late for 

 chemicals to be effective. Keep weeds under control in August and September to 

 help reduce the problem for next year. 



Corn leaf aphids were found in the whorl leaves of corn for the first time this 

 week. There were just a few aphids in occasional plants in the field. It is too 

 soon to make predictions on this insect. 



Occasional fields of corn and soybeans are being damaged by white grubs . These 

 large grubs will stop feeding and pupate soon, and nothing can be done to protect 

 the planting at this time. The grubs caused injury in these same fields in 1966-- 

 fields that had not been treated in previous years with a soil insecticide. 



Forage Insects 



Potato leafhoppers do not appear as abundant this year as in the past. No yellow- 

 ing of second- growth alfalfa was observed this week. However, if swarms of these 

 small (1/16- inch), green, wedged-shaped insects are observed on the new growth of 

 the second crop, or at the time the second crop is cut, treatment is indicated. 

 Use either carbaryl (Sevin) or methoxychlor at 1 pound per acre. Allow 7 days to 

 elapse between treatment and harvest when using methoxychlor. There is no wait- 

 ing period for carbaryl. 



A few small garden webworms were observed in alfalfa in the southwestern section. 

 It is too soon to make accurate predictions on this insect. Normally, this in- 

 sect is most destructive in late summer on new seedings of alfalfa. 



Livestock Insects 



Horn flies and stable flies are increasing on pastured cattle. A few face flies 

 were also observed on pastured cattle. Begin control programs now before the 

 flies become numerous. When abundant, these flies can easily reduce milk flow 

 by 15 to 20 percent and beef gains as much as a half pound per day. It is not 

 difficult to pick up an extra $10 per animal over and above treatment costs by 

 using an effective control program. 



For pastured dairy cattle, apply 1 to 2 ounces of an oil -base spray of 2 percent 

 Ciodrin per animal, every 3 to 4 days for best results. A 1-percent dichlorvos 

 (DDVP) or 0.1 -percent pyrethrin oil-base spray applied at the rate of 1 or 2 

 ounces per animal every day or two can also be used. But these are less effec- 

 tive than Ciodrin, particularly against the face fly. Water-base sprays of the 

 same material may be used, but control is less effective. Pay particular atten- 

 tion to the animal's legs and undersides when spraying. 



