Nor is this:

BP's favorite dispersant Corexit 9500 is being sprayed at the oil gusher on the ocean floor. Corexit is also being air sprayed across hundreds of miles of oil slicks all across the gulf. There have been widespread reports of oil cleanup crews reporting various injuries including respiratory distress, dizziness and headaches.
The real problem is not the dispersants themselves but what the chemicals do to the oil. By itself, oil is more toxic than dispersants alone, but together oil and Corexit is far more toxic. I can only assume the EPA approved Corexit because they thought diluting the dispersed oil and Corexit will mitigate its increased toxicity.
A mysterious "disease" has caused widespread damage to plants from weeds to farmed organic and conventionally grown crops. There is very strong suspicion that ocean winds have blown Corexit aerosol plumes or droplets and that dispersants have caused the unexplained widespread damage or "disease".

There is no other explanation for the crop damage. It's conjecture on my part but everything points to something that has a widespread effect on plants and crops. Studies on Corexit and its effects on plants are consistent with the damage sustained in the lower Mississippi area.