Plant studies have been carried out to identify the nature and extent of the formation of adducts with DNA bases when treated with pesticide formulations. DNA extracted from crop plants after treatment with pesticide formulations has yielded evidence of adduct formation. The extent of DNA modification has been established by (32)P postlabeling studies. The radiochromatograms from (32)P postlabeling of isolated plant DNA from grapes, bush beans, soybeans, pumpkins, and cucumbers show elevated adduct levels in treated vegetable plants as compared with untreated controls. A number of different adduct spots appear, likely indicating adduct formation with pesticide molecules or their metabolites. The DNA adducts from hexenal and 4-hydroxy-2-nonenal were clearly observed, indicating oxidative stress and lipid peroxidation in the plant.