Fletcher Scale Control on Taxus, 1980

A field of nursery grown 10-18 in Taxus infested with Fletcher scale was selected for insecticide evaluation. Eight insecticides were tested at 2 rates plus a control. Scale egg hatch occurred on Jun 25 and all crawlers were firmly attached to the needles by the time of the test on July 10. Each treatment was replicated 6 times in a randomized block design. Chemicals were applied with a tractor mounted hydraulic sprayer operating at 40 psi. All plants were sprayed to run off. Sunny conditions persisted at treatment time with an air temperature of 86°F and a light breeze (<8 mph). Less than 0.5 inch of rain occurred 1 day prior to treatment with no rain for 5 days post treatment. Plants were sampled at 1, 2 and 4 week intervals following treatment. The number of live and dead scale nymphs were counted on 40 needles/plant: 10 needles from each of 4, 1-2 year old twigs sampled randomly from each cardinal direction of the plant. Percentage data were transformed using arcsine and analyzed by ANOVA.