X^- 7 



FOR IMMEDIATE RELEASE August Ik, 1964 



FINAL ISSUE 



This is the eighteenth and final issue in a series of weekly bulletins on 

 the general insect situation in Illinois (fruit insects excepted), prepared by entomol- 

 ogists of the University of Illinois College of Agriculture, Illinois Natural History 

 Survey and cooperating agencies, It is designed to forewarn people in Illinois of im- 

 pending changes in insect activity and to suggest abbreviated control measures. These 

 reports indicate only general trends. Each individual should check his own fields to 

 determine local conditions. 



Corn borer moth emergence is complete south of Highway 6 and is rapidly near- 

 ing completion north of this line. In the western section between Highways 9 and 6, 

 where borer development is slightly ahead of the northern section, egg counts averaged 

 100 to 500 per 100 plants in late -maturing field corn. Approximately 30 to 75 percent 

 of these eggs have hatched. Egg-laying will continue at a decreasing rate in this 

 area for the next 10 days to two weeks. 



North of Highway 6, egg-laying has just begun, and counts range from 20 to 

 200 per 100 plants in late-maturing field corn. Egg hatch is just beginning. Egg- 

 laying should continue for another two to three weeks. 



The potentially threatened area lies north of Highway 9, with the heaviest 

 populations in the western and northwestern sections. It is the late -maturing fields 

 in which the moths will concentrate their egg-laying. However, check early- and 

 medium-maturing fields, since emerging moths lay some eggs here before moving into 

 the late corn. 



If there are 100 or more egg masses per 100 plants, treatment will be profit- 

 able. Apply 1 pound of actual DDT or l-l/2 to 2 pounds of actual carbaryl (Sevin) per 

 acre as granules. For spraying, use l-l/2 pounds of actual DDT per acre, and direct 

 the spray to cover the upper half of the corn plant, including the ear. Do not use 

 DDT on corn to be fed as ensilage or stover. Aerial applications should be granules, 

 not sprays or dusts. Phorate (Thimet) and diazinon as granules also have label ap- 

 proval for corn borer control. 



Corn leaf aphids are being killed by disease, parasites and predators. 

 Fields observed this week showed from 25 to 90 percent mortality of aphid populations. 

 No insecticide treatments should be needed to control this pest. 



Chinch bugs are reported in moderate .to. b^vy^ numbers in such grasses as 

 millet, sudan, sudax and others, as well as in L 6^ca : sion&i£ cornfields in central and 

 eastern Illinois. These small bright to dar^jradj insects are the second-generation 

 nymphs. Some first -generation adults are also still 'present. There is no effective 

 insecticide that is safe to use on grass c#|Jj|g|?$e^rgd, f jf«r livestock forage. Nor- 

 mally by this time corn is sufficiently mature "to witnstarid fairly large numbers with- 

 out serious injury, but stress from drought could intensify the injury. 



Soybeans are being attacked by bean leaf beetles, grasshoppers, green clover- 

 worms and garden webworms, particularly in the west-southwestern, central and northern 

 sections. Bean leaf beetles were observed feeding on blossoms in addition to leaves 

 this week. No report of injury to pods has yet been received. 



Treatment is not warranted unless the insects attack pods or blossoms or un- 

 less defoliation is severe. If treatment becomes necessary, use 1-1/2 pounds of toxa- 

 phene per acre, but do not use the foliage as feed for livestock. There is no time 

 limitation on combining of beans. Do not apply toxaphene near fish -bearing waters or 

 fields of dairy hay or pasture. 



