According to the Spinosad General Fact Sheet of the National Pesticide Information Center, “Spinosad is a natural substance made by a soil bacterium that can be toxic to insects. It is a mixture of two chemicals called spinosyn A and spinosyn D. It is used to control a wide variety of pests. These include thrips, leaf miners, spider mites, mosquitoes, ants, fruit flies and others.” It is approved for use on organic gardens by Organic Materials Review Institute, or OMRI. One caution with its use: In high concentrations, it can be toxic to honey and native bees, so we should only spray when bees are not present on our trees.