Collect the most recently matured leaves from 35 to 50 plants selected at random in problem area or field. Care and handling of samples Start with a paper bag. A kraft paper bag is ideal for collecting, drying and mailing samples. It must be clean. New, unused bags are available at most grocers.
Smaller ones are suitable for soybeans and other crops.
Sample kits available from commercial laboratories also are suitable. Carry an open bag. Drop the leaves in the open bag as the tissue is removed from a plant. Leave them loose to allow for air drying. Do not wad or tie the leaves into a bundle, or heating and molding may occur.