Cotoneaster, Control of Two-Spotted Spider Mite, Lake County, Ohio, 1989

Cotoneaster growing in 1-gal (3.91) containers at a nursery in Lake County were used to evaluate efficacy of selected pesticides against two-spotted spider mites. A C02 compression sprayer at 20 psi with a single Teejet SS8004 flat-fan nozzle was used to apply treatments to runoff. Infested plants were selected at random and placed in groups of 6 replicates/ treatment. The first application was applied to all plants 24 Jul when conditions were sunny, 30°C, with 8-16 kph winds; second applications were made to selected plants 3 Aug with conditions sunny, 30°C, and 16-24 kph winds. Treatments were evaluated 1, 2, and 3 wk after second application by removing five, 10-13 cm long branch tips from each of the 6 replicates/treatment. Samples were placed in plastic bags and transported, in coolers, to the laboratory. All samples were processed by passing them through a mite brusher 6 times to dislodge mites to a rotating glass plate coated with Tween-20. Dislodged mites were counted with the aid of a binocular dissecting microscope.