In this article, we study model-theoretic properties of algebraic differential equations of order 2, defined over constant differential fields. In particular, we show that the existentially closed theory associated to a "general" differential equation of order 2 and of degree d ≥ 3 is almost strongly minimal and disintegrated. We also formulate -in the language of algebraic varieties endowed with vector fields -a geometric counterpart of this model-theoretic result.These results provide a positive answer, concerning planar vector fields, to a conjecture of Poizat in [Poi82], slightly strengthened in [Poi95], asserting that (the generic type of) a "general" differential equation of order n ≥ 2 is always disintegrated.