PER CURIAM.
Appellant seeks review of a conviction, following a jury trial, for possession of more than 20 grams of cannabis. The state's case was based on constructive possession. Appellant denied knowledge that the cannabis was present. This placed in dispute the essential element of knowledge of the illicit nature of the substance, as well as that of knowledge of the presence of the substance. Scott v. State, 808 So.2d 166 (Fla. 2002); Blunt v. State, 831 So.2d 770 (Fla. 4th DCA 2002). Accordingly, failure to instruct the jury on the element of knowledge of the illicit nature of the substance constituted fundamental error, entitling appellant to a new trial. Reed v. State, 27 Fla. L. Weekly S1045 (Fla. Dec. 19, 2002); Blunt, 831 So.2d at 771-72. Section 893.101, Florida Statutes (2002), may not be applied retroactively to this case because the offense was alleged to have occurred before that statute was enacted. Norman v. State, 826 So.2d 440 (Fla. 1st DCA 2002).
REVERSED and REMANDED, with directions.
BOOTH, WEBSTER and LEWIS, JJ., CONCUR.