Black cutworm damage reports , although not numerous , are more common this year than last 

 Check low spots on fields. If plants are being cut above the growing point of the corn 

 and if the worms are all over 1 inch long, the outbreak will be over very shortly, and the 

 corn will continue to grow. However, you should treat immediately if the plants are being 

 cut off below the growing point and many worms are less than an inch long. Direct the 

 spray at the base of the plants ; use carbaryl (Sevin) at 2 or 3 pounds , diazinon at 2 

 pounds, toxaphene at 3 pounds, or trichlorfon (Dylox) at 1 pound of actual chemical per 

 acre in at least 20 gallons of water per acre; also, cover the spray by throwing soil at 

 the base of the plants with a cultivator . 







Corn rootworm eggs will begin to hatch this week in the north half of Illinois. Poten- 

 tially, fields of continuous corn in the northern half of Illinois may be affected. Many 

 fields of second-year corn north and west of a line from Dixon to Peoria to Stronghurst 

 may be damaged by the western corn rootworm . Other fields of second-year corn to the east 

 and north of this line may also be damaged. The northern corn rootworm is most abundant 

 north of Highway 36 (Pittsfield to Springfield to Decatur) , and is often a problem in fieL; 

 where corn has been grown continuously for three or more years in the same field. 



I 

 If you suspect or know that you have a resistant western or northern corn-rootworm prob- 

 lem and if you did not use an organic phosphate or carbamate insecticide at planting time, 

 apply one of these within the next two weeks. Use granules applied at the base of the con 

 plants, and cover them by cultivation. A special applicator on the cultivator directs the 

 phosphate granules at the base of the plant, and dirt is thrown over this deposit. 



Organic phosphate or carbamate insecticides are the only effective means of controlling 

 resistant rootworms . The following materials have label approval for basal application 

 and are recommended for control of resistant rootworms in Illinois. 



Rate per 



Insecticide acre (lb.) 



*BUXten I 



Diazinon 1 



Disulfoton (Disyston) 1 



Parathion (Niran) 1 



Phorate (Thimet) 1 



Carbaryl (Sevin) 2 





*Note : Effective June 1, 1969, BUXten 

 granular has been granted USDA 

 registration for use as a basal 

 application for corn rootworm 

 larval control in field corn. 

 For best results, make the ap- 

 plication before June 15 . 



In northern Illinois, the big question relates to rainfall and the effectiveness of plantin- 

 time applications of rootworm insecticides. Did the 3- to 6-inch rains take the insecticid 

 out of the rootworm zone? This is likely to vary with insecticides. Check the root systeir 

 of plants this week and during the next two weeks for the infestations. If you find 5 or 

 more worms per plant, use a basal application. 



Small worms are hard to find. Dig up the plant. Put the roots in a plastic bag. Examine 

 the bag for tiny rootworms two times at 24-hour intervals. In another 10 days, the root- 

 worms will probably be large enough to be seen in the field by shaking the roots over a 

 piece of canvas or plastic. At this time, also tear open the roots; many rootworms are 

 actually in them. 



