(19)

(11)

EP 0 493 471 A1

(12)

(43) Date of publication: 08.07.1992 Bulletin 1992/28 (21) Application number: 90914319.0 (22) Date of filing: 19.09.1990

(51) International Patent Classification (IPC):  A01N 25/ 04( . ) (86) International application number: PCT/US1990/005213 (87) International publication number: WO 1991/003937 (04.04.1991 Gazette 1991/08)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB IT LI LU NL SE (30) Priority: 21.09.1989 US 19890410656 (71) Applicant: E.I. DU PONT DE NEMOURS AND COMPANY Wilmington Delaware 19898 (US)	(72) Inventor: HERMANSKY, Clarence, Gaetano Wilmington, DE 19810 (US) (74) Representative: Hildyard, Edward Martin  Frank B. Dehn & Co. Imperial House 15-19 Kingsway London WC2B 6UZ London WC2B 6UZ (GB)