Life Cycle: Citricola scale, Coccus pseudomagnoliarum, has one generation per year. Females produce eggs in May-June that hatch into crawlers that move to leaves. The crawlers settle down as nymphs that do not molt until fall. The 2nd instars move to the twigs and overwinter. In the spring the 2nd instars move to the tips of the twigs and become adult females. There are no males.
Host List: Citricola scale is found primarily on citrus.
Damage: Citrus yield is significantly reduced if densities of adult scales exceed 1 per twig or densities of 1st instar nymphs exceed 0.5/leaf. In addition, sooty mold grows on the honeydew produced by the scales and this can result in downgrading of the fruit if it can not be washed.
Distribution: Originally from Asia, in California citricola scale is found primarily in the San Joaquin Valley because of lack of effective biological control in that region.