What was done
Bean (Phaseolus vulgaris) plants were grown in controlled environments receiving atmospheric CO2 concentrations of 350 and 700 ppm.  After 15 days of differential CO2 exposure, the destructive agricultural mite Tetranychus urticae was added to bean foliage to determine the effects of elevated CO2 on its colonization and reproductive success.

What was learned
Atmospheric CO2 enrichment increased plant dry weight by 65%.  In addition, elevated CO2 increased leaf starch content by 100%, but it reduced leaf nitrogen contents by about 25%.  These CO2-induced changes in leaf chemistry likely contributed to individual female mites producing 34 and 49% less offspring on CO2-enriched foliage in the first and second generations, respectively, in comparison with progeny produced by mites feeding upon ambiently-grown foliage.

What it means
As the CO2 concentration of the air continues to rise, it is likely that this invasive mite, which negatively affects more than 150 crop species, will exhibit reduced reproductive success and subsequent colonization of bean foliage.  If these results are typical of the mite's relationship with other agricultural plants, it is conceivable that yields of many crops will increase dramatically due to CO2-induced increases in plant growth and yield and concomitant decreases in damage caused by Tetranychus urticae.