Environmental degradation caused by the excessive use of pesticides has motivated studies aimed at the discovery of new formulations for pest control. The bioassays carried out under laboratory conditions for the present study involved the germination and seedling growth of Lactuca sativa cv. Grand Rapids and Allium cepa cv. Baia Periforme treated with lecanoric acid or one of seven esters obtained from the alcoholysis of the acid. Each substance was tested at concentrations of 10-3, 10-5, 10-7 M, and 10-9 M. The results revealed that, except for lecanoric acid and methyl orsellinate, all other compounds exhibited significant differences in their action when compared with the controls. Also, A. cepa was more sensitive to the compounds assayed, at the concentrations tested. Nearly all the esters exhibited significant effects, a feature that could makes them promising for the development of new natural herbicides.
allelopathy; germination; growth; Lactuca sativa; Allium cepa; orsellinates
