7 



COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 URBANA-CHAMPAIGN 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA. ILLINOIS 



^SECT, WEED & PLANT DISEASE SURVEY BULLETIN 



ATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IWEDIATE RELEASE 



SPECIAL ISSUE NO. 



JUL 



No. 22, January 15, 1971 



This will be the last issue of 1970-series bid '.3~i->:s. 



Greenbugs : These are aphids that ordinarily attack cereal grains, and are serious 

 pests. They transmit diseases of small grains; in addition, they secrete a toxin in- 

 to the plant that kills the tissue. Large, dead areas appear in grain fields. 



We have had damage to small grains by this pest in four of the last twenty- five years. 

 These insects probably migrated from Arkansas, Kansas, Oklahoma, or Texas. Such mi- 

 grations occur when the winds are predominantly from the Southwest, at the particular 

 time when the aphids develop wings because they are overcrowded on the host plants. 

 The winds then drop them across the Midwest. We doubt that the overwintering of green- 

 bugs in Illinois is extensive. Therefore, outbreaks occur only when migrations are 

 unusually large. 



Recently, in the Great Plains States, a new strain of this pest attacked sorghum. Sev- 

 eral different phosphates, such as malathion, diazinon, and the like, control this 

 pest; but they may have a depressing effect on aphid predators as lady beetles. Some 

 states report that demeton (Systox) has controlled this aphid by systemic action, with- 

 out the extensive loss of predators. This insecticide should not be used at more than 

 0.25 pounds per acre, within 55 days of harvest, and not more than once per season. 

 Demeton should be applied by experienced applicators only. 



We, in Illinois, are watchful because greenbugs killed-out patches of grass lawns in 

 central and eastern Illinois this fall. We have not seen blue grass damage before 

 1970, when they killed the blue grass but did not attack the fescue. Tie strain of 

 greenbugs involved is not known. 



Therefore, watch sorghum for this pest this summer. Most of the aphids you find will 

 be corn leaf aphids, which are usually not important in sorghum production. 



The corn leaf aphid is a bluish-green aphid with a velvety appearance; all legs, cor- 

 nicles, and antennae are black. Greenbugs are yellowish or bright green, with a red- 

 dish tinge on the back of the body - ! Only the tips of cornicles and antennae are black. 

 When in doubt, send samples to us for a check. 



European corn borer : Several persons have asked if carbofuran (Furadanl , as a planting- 

 time soil insecticide for rootworm, would be effective in controlling first -generation 

 European corn borers. Our experience for the past two years leads us to say no. Iowa 

 State Information Letter Xo. 18 states, "Questions have been raised about the value of 

 Furadan applied at planting time for rootworm. control, as a systemic for corn borer con- 

 trol. The Corn Borer Laboratory says it doesn't do the job ." 



Higher rates or basal applications during the late cultivation period may control corn 

 borers, but higher planting-time rates than the ones used for rootworm do not have 

 label approval, and basal applications at cultivation do not have approval. 



