Experimental Limits on Weak Annihilation Contributions to b{yields}ul{nu} Decays

We present the first experimental limits on high-q{sup 2} contributions to charmless semileptonic B decays of the form expected from the weak annihilation (WA) decay mechanism. Such contributions could bias determinations of vertical bar V{sub ub} vertical bar from inclusive measurements of B{yields}X{sub u}l{nu}. Using a wide range of models based on available theoretical input we set a limit of {gamma}{sub WA}/{gamma}{sub b{yields}}{sub u}