Greenbug: Schizaphis graminum
English grain aphid: Macrosiphum avenae
Cherry oat aphid: Rhopalosiphum padi
Greenbug is a serious pest of wheat due to the fact that it injects a toxin while feeding. However, the greenbug rarely occurs in Ohio.
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Other aphids - including the English grain aphid and the cherry oat aphid - may cause limited injury due to feeding injury, but they do not secret a toxin that stunts the plant growth.
The first step in assessment of an aphid problem on wheat is to accurately identify the infestation.
Greenbugs have a dark green stripe on their back and the tips of the cornicles (tailpipes) are black.
Cornicles of the English grain aphid are totally black. The cherry oat aphid has a red-orange spot between the cornicles.
If the infestation is greenbug, treatment is warranted when an average of 50 or more greenbugs are found per linear foot of row in the fall or 100 or more greenbugs per linear foot of row in the spring.
Materials recommended for control of greenbug outbreaks include:
Dimethoate 2.67 @ 3/4-1 pt/A and 400 @ 1/2-3/4 pt/A
Dimate 2.67 @ 3/4-1 pt/A and 4E @ 1/2-3/4 pt/A
Lannate* SP @ 1/4-1/2 lb/A,& LV @ 3/4-1 1/2 pt/A
Malathion 5 @ 1-1 1/2 pt/A and 57 @ 2pt/A
Penncap-M* @ 2-3 pt/A.
Phaser 3EC @ 2/3 to 1 lb/A
Warrior* 1CS @ 3.84 fl oz/A
* Use is restricted to certified applicators
Aphids other than greenbugs are generally maintained at sub-economic levels by beneficial parasites and predators.