Hey man.
I have used the below organic pesticide when my one auto had some red spider mites and worked wonders. Not so sure about when in flowering as I see it contains canola oil, also I presume it's much the same as the Ludwig's pesticide you mentioned, but worth a try maybe...
https://hydroponic.co.za/hydroponics/margaret-roberts-organic-insecticide/?attribute_pa_size=500ml&gclid=Cj0KCQjw4fHkBRDcARIsACV58_GF_OL149SezUe595LgZ3Ch4u2USozFuN4OGZjTCn0bfsGaTNMcX2MaAmL2EALw_wcB