What was done
The author reviewed the scientific literature dealing with effects of elevated levels of atmospheric ozone and CO2 on aphid-host plant interactions.

What was learned
After compiling the results of 26 studies dealing with aphid-host plant interactions in the presence of CO2-enriched air, the author noted that exposure to air of elevated CO2 concentration increased aphid performance in six studies, decreased it in six studies, and had no significant impact on it in the remaining 14 studies.  Similar results were found for aphid-host plant interactions in the presence of elevated ozone concentrations.

What it means
As the air's CO2 concentration continues to rise, and perhaps its ozone concentration as well, aphids likely will not exhibit increased outbreaks on plants.  Indeed, after reviewing the literature in this area, the author concluded that "ozone and CO2 do not cause an unambiguous positive [aphid] growth response as do other gaseous pollutants."  Hence, we need not worry about dire predictions of an end to monocultural food production due to increased aphid activity in a CO2-enriched world.