-?- 



Use 1 pound of actual diazinon in granular form per acre of 1-1/2 pounds of carbaryl 

 (Sevin) as granules. For spraying, use the same amount of actual insecticide per 

 acre, and direct the spray to the upper third of the plant. Aerial applications should 

 be granules, not sprays or dusts. Allow 10 days between treatment and the ensiling of 

 corn when applying diazinon; carbaryl has no waiting period. Commercial applicators 

 may prefer to use parathion at 1/2 pound actual per acre, which will provide good con- 

 trol of the corn borer. Parathion has a 12-day waiting period between treatment and 

 harvest . 



Reports on corn-borer development were received from Warren Bundy at Edwardsville , 

 Bob Hayward at Mt. Sterling, Jim Paullus at Rochelle, and Mike Sager at Eureka. 



Com rootworm egg-harch will continue over the next several weeks. The peak number 

 of larvae is expected in early to mid-July. Many fields of continuous corn in the 

 northern half of Illinois may be affected, even though there were fewer adult root- 

 worms in 1969 than for several years. Fields of second-year corn, north and west of 

 a line from Carthage to Bloomington, to LaSalle, to Joliet may be damaged by the 

 western corn rootworm . The concentration of northern corn rootworms is greatest 

 north of U.S. Highway 36, often presenting a problem where corn has been grown con- 

 tinuously for three or more years in the same field. 



If you know about or suspect that you have a rootworm problem and did not use an 

 organic phosphate or carbamate insecticide at planting time, apply one within the 

 next two weeks. Use granules applied at the base of the plants, and cover them by 

 cultivation. The insecticides suggested for basal treatment are BUXten, Dasanit, 

 or phorate (Thimet)--at the rate of 1 pound of actual chemical per acre. 



Common stalk borers are moving out of the grasses and weeds found in fence rows , road- 

 sides, grass waterways, and ditchbanks and into the border rows of corn. These whitish- 

 brown, striped worms with a distinct purple band around their middle feed in the whorl 

 of the corn. The emerging leaves will have irregular holes in them. Plants may be 

 severely damaged, sometimes killed, by these insects. Control in corn is difficult, 

 because the worms are usually too deep in the whorl for insecticides to reach them. 

 In cases of severe infestations try the following suggestion: 



Mow the grasses and weeds from which the borers are migrating. A rotary mower would 

 be best, in order to help kill some of the worms during cutting. This will drive the 

 worms out of these areas and into the corn. Therefore, spray the mowed area and the 

 first few rows of corn immediately with 1-1/2 pounds of actual carbaryl (Sevin) per 

 acre. This should help reduce further infestations and additional damage. 



Thrips are common in corn whorls, especially in the southern section of the state. 

 Both the yellow and black grass thrips are present. They are tiny (about 1/16 of an 

 inch) and leave tiny streaks of white mottling on the leaves. The feeding damage is 

 being mistaken for that caused by flea beetles, which leave a more -distinct , white 

 groove or scratch mark on the leaves. When numerous, the thrips, cause a field to 

 take on a silvery appearance. Insecticides are seldom needed to control thrips on 

 corn. However, if severe damage occurs, a spray of 1 pound of malathion per acre 

 directed into the whorl should control them. 



SMALL GRAINS 



The threat from true armyworms is subsiding as the worms mature and various diseases 

 and parasites take their toll . Scattered reports have been received of armyworm mi- 

 grations from grass pastures, hay fields, and wheat into corn. Large areas of small 

 corn can be damaged overnight by a hungry horde of armyworms. 



