If your pet is refusing food don’t push the matter. Make sure they always have enough water to drink. Ice cubes or vegetable broth are easier for them to ingest. Try and ensure that he or she doesn’t get dehydrated. In the case of diarrhea, Pepto Bismol (given with a syringe if you have to; good luck!) can alleviate the situation. If the situation is not better by the second day, call your vet.
Although citronella is advertised as a mosquito deterrent, the plant itself does not repel the insects. Citronella oils, ointments, sprays, candles and incense have been shown to work effectively against mosquitos. If by mosquito plant, you are referring instead to duckweed ferns or vervain, the ASPCA does not warn against them. For future reference the ASPCA has an online list of toxic and non-toxic plants at www.aspca.org/pet-care/poison-control/plants/