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The maturity of corn varies greatly from field to field within an area. Some fields 

 are pollinating and some are still in the late-whorl stage. With the time of beetle 

 emergence about normal and with some late fields, it is more likely that rootworm 

 beetles will affect pollination this year than in the past. Examine fields this week 

 that are just starting to silk or are less than 50-percent pollinated. Treat if nec- 

 essary. 



Count beetles per ear for the next four weeks. If you average 1 or more beetles per 

 ear each week, this field may profit from a soil- insecticide treatment next spring, if 

 planted in corn. 



Corn leaf aphids are multiplying, but we did not see any fields that were being seri- 

 ously damaged this past week. These aphids do not multiply until the plants are in 

 the late-whorl stage, decreasing rapidly after the silks have turned brown. Therefore, 

 the late-whorl to pollination stage of growth is critical. This week, observe fields 

 from the whorl stage to early silk in maturity. If over 50 percent of the plants have 

 a moderate infestation, apply malathion or diazinon if moisture is low. With diazinon, 

 allow 7 days between application and harvest for corn used as ensilage; 3 days for mal- 

 athion. 



In seed fields which are being detasselled, do not use phorate (Thimet) granules. 



Aphid damage is much more severe in drought years or in dry areas that have missed 

 the rains. It now appears that aphids will not present a general problem in the north- 

 ern third of Illinois*. Rainfall has been spotty in the southern two- thirds of the state, 

 Late fields of corn in these areas should be examined for aphids. 



Fall armyworms may soon appear in late-maturing cornfields or in replanted spots in 

 fields. Several plants in one spot are usually affected. These worms are greyish 

 brown, and can usually be found in the whorls. The leaves are very ragged as they 

 emerge . 



After the worms are deep in the whorl, control is difficult. But if they are still 

 in the open in the whorl, sprays of carbaryl, diazinon, Gardona, and toxaphene will 

 control them. 



SOYBEAN INSECTS 



Striped blister beetles are now defoliating plants. It is common to have them in one 

 spot in a field. Hundreds of individuals are usually present. If you squash them on 

 exposed tender skin (such as the forearm or neck) , blisters will form. If soybean dam- 

 age from these beetles is sufficient, apply carbaryl as a spray. Yellow leaves on plant: 

 along the edges of fields is not caused by insect feeding, but is more likely to be the 

 result of a plant food deficiency. 



LIVESTOCK INSECTS 



Face flies have increased rapidly in number during the last two weeks, and are now both- 

 ering pastured cattle. The state average this past week was about 25 face flies per an- 

 imal, with individual herds averaging as high as 38 per animal. Infested cattle often 

 develop eye problems, besides the constant irritation caused by the flies. Face flies 

 may also transmit pinkeye disease among cattle. 



For control on dairy cattle, apply a 2-percent crotoxyphos (Ciodrin) oil-base spray (if 

 available) or a water-base spray at 1 to 2 ounces per animal, as often as once a day if 

 needed. In order to prevent another buildup, continue to apply the crotoxyphos two to 



