You're asking the wrong question, you should ask if spinosad is systemic.
You can add it to feed, if you got something in the roots.
It's translaminar mostly.
Some insecticides/miticides have translaminar, or local, systemic activity. These materials penetrate leaf tissues and form a reservoir of active ingredient within the leaf. This provides residual activity against certain foliar-feeding insects and mites. Insecticides/miticides with translaminar properties include aba-mectin (Avid), pyriproxyfen (Distance), chlorfenapyr (Pylon), spinosad (Conserve), and acephate (Orthene). In general, these types of materials are active against spider mites and/or leafminers. Because the active ingredient can move through plant tissues (that is, leaves), thorough spray coverage is less critical when using these materials to control spider mites, which normally feed on leaf undersides.