Walton, W. R. The hessian fly and how losses from it can be avoided / by W. R. Walton and C. M. Packard - Washington : Department of Agriculture - 14 p. - EUA. Dep. of Agri. Farmers' bull.; 1627 . LCCN: 203989 Subjects--Topical Terms: Phytophaga destructor Control de plagas