An agricultural composition comprising the chemical formula, or salt thereof, of: ##STR1##

• wherein Rx is —NH₂, —OH, halogen, akylamino, SR₁, carboxyalkyl, carboxy, or a sulfonamide moiety, wherein R₁ is a H or a C₁ to C₆ alkyl moiety, and Ry and Rz, independently, are electron donating groups and an agriculturally acceptable carrier.