Factors Affecting Biological Control of Scale Insects on Texas Citrus

Biological control of citrus insects has been an important economic consideration in the Lower Rio Grande Valley citrus area during the past 20 years. Many growers who applied chemicals to control scale insects on an extensive basis found that their neighbors who used no chemical sprays profited as well and did not upset a predator-pest relationship in nature. Yearly spray operations seemed necessary once the grower started spraying. Other pests, for which the man did not spray, often developed to damaging numbers. Growers, thus, directed chemical control efforts against the two most important pests: the citrus rust mite, Phyllocoptruta oleivora (Ashm.) and Texas citrus spider mite, Eutetranychus banksi McG. At the present time, sprays are not commonly used in the area and dusts are the common means of applying chemicals for the control of these pests.