Ficus are known to drop leaves in the spring and fall because of the change in the location of the sun. Also over or under watering could cause leaf drop. It is doubtful that Malathion would have caused the problem. Ficus plant has tiny insects and leaves are speckled yellow. Use approved miticide for use indoors.
Mites are difficult to control.
Gardenia plant growing indoors won't bloom even though it appears healthy. Gardenias kept indoors must have high humidity and cool nights as well as plenty of sunlight. The plant will not set buds if night temperatures exceed 65 degrees F. 35. As with all plants, the more light the better. I was looking for basic information on growing, varieties and medical properties of aloe vera.