applied at the base of the plant adding nutritional value to the mixture the preferable ratios of chemical compounds in the mixture are 250 ml of h 2 o to 24 3 g of caco 3 to 1 06 u00d7 10 u2212 5 g of h 2 s the following is the structural formula for the pest repellant a mixture of hydrogen sulfide and calcium suspended in water as mentioned above was applied to a poinsettia plant the poinsettia plant was placed near a gardenia bush that was infested with white flies the poinsettia plant was monitored and visually inspected bi weekly for approximately five months during warm weather visual inspections of the poinsettia plant revealed no white flies larvae or white fly eggs present on the leaves of the poinsettia plant the plant remained healthy and productive with blossoms and leaves of deep color a gardenia bush that was infested with white flies operated as a control white flies were visibly present on the leave surface of the gardenia bush a second gardenia bush was placed within approximately a foot of the control the second gardenia bush was treated twice a month with a mixture containing 0 424 mg l of h 2 s as mentioned above visual inspections of the gardenia bushes were conducted over a four month period of time while the control remained infested with white flies no white flies were present during the visual inspections on the second gardenia.