It is hereby declared as a matter of legislative determination that the common barberry, Berberis vulgaris, its horticultural varieties and Berberis, Mahonia and Mahoberberis are the alternate host plants of a plant disease known as black stem rust; that the plant disease, black stem rust, is caused by an organism known as Puccinia graminis which attacks wheat, oats, barley, rye and other cultivated plants and wild grasses; that the spread of said black stem rust to the agricultural crops and wild grasses of this state cause great financial loss to the growers of these crops and to the agricultural interests of this state.