Family CurculionidaeRiaan kindly supplied me with the following information:
"Alien from Middle America. In South Africa since 1975. Quite a severe pest of most (?all) species of Agave. Very serious pest of fibre sisal plantations and tequila plantations in Mexico. In South Africa destructive of fibre sisal, ornamental agaves, and our now-defunct Karoo "tequila" industry. "
Identification by Riaan Stals http://www.ispot.org.za/node/158698