A method for UV (ultraviolet) fluorescence counting of selected biological masses, such as egg masses, on foliage samples comprising the steps of: exposing a foliage sample having attached egg masses to UV radiation by a scanning beam; discriminating between the fluoresced light due to the masses and the fluoresced light due to other biological or foliage components; and counting the egg masses based upon the fluoresced light emitted by the egg masses. Also, an apparatus for UV fluorescence counting of egg masses on foliage samples is provided comprising a sample feed means having a test chamber; combined electro-optical sample scanner, fluorescent light divider, and detector; and an electronic signal discriminator and counter for selecting the divided fluorescent light signals emitted by egg masses from the emitted light of other foliage components, to thereby provide a count of the egg masses.