You may be thinking of a dormant oil spray. It is a horticultural oil that you use in the winter when plants are dormant and it coats the cracks and crevices of fruit trees and roses to smother insect eggs and disease spores. It must be applied when these plants are leaf less. I am not familiar with a spray to use on insect eggs when the leaves are out in the spring. There are several types of insecticides to use on adult white fly and aphid while plants are growing. These use malathion or diazinon to control insect outbreaks and like the dormant oil spray are available at garden centers. Keep growing, Marianne Binetti