Spencer, IA: (May 23, 2012) - Monsanto is hitting back at the emerging army of herbicide-resistant weeds spreading across the cornbelt by moving into the field of biologics.
 
The effort includes products made from natural materials and is in the midst of developing a spray that targets the mechanism in weeds that allows them to survive herbicide.
 
The emergence of resistant weeds has sent seed and chemical companies scrambling for new products.