Research Summary Abstract
Managing scale insects presents unique challenges. Products with contact modes of action must be applied at specific timings in order to reach the most susceptible crawler stages. Products with systemic modes of action may work well for certain species and not others based on application timing and whether the insect feeds within phloem. In 2003, IR-4 initiated a high priority project to determine efficacy of several insecticides on several scale and mealybug species so data can be obtained to add appropriate species to existing registrations. This research was conducted between 2004 and 2022, and this summary contains outcomes from 85 experiments received through the IR-4 Environmental Horticulture Program. Across the 24 scale species screened, the most efficacious products included ISM-555, RTSA-721, XXpire, horticultural oils, Talus, Rycar, Distance, Safari, Ventigra, dimethoate. Kontos, Tristar, Altus, Flagship, Mainspring, and Marathon also reduced populations. However, sensitivities across species varied by product and application method.