Let V ∈ Q(i)(a 1 , . . . , a n )(q 1 , q 2 ) be a rationally parametrized planar homogeneous potential of homogeneity degree k = −2, 0, 2. We design an algorithm that computes polynomial necessary conditions on the parameters (a 1 , . . . , a n ) such that the dynamical system associated to the potential V is integrable. These conditions originate from those of the Morales-Ramis-Simó integrability criterion near all Darboux points. The implementation of the algorithm allows to treat applications that were out of reach before, for instance concerning the nonintegrability of polynomial potentials up to degree 9. Another striking application is the first complete proof of the non-integrability of the collinear three body problem.