Spider mites in the landscape and nursery
Editor’s note: This article is from the archives of the MSU Crop Advisory Team
Alerts. Check the label of any pesticide referenced to ensure your use is
The warm, dry weather patterns that have continued across much of Michigan have caused some outbreaks of spider mites in both the landscape and nurseries. Plants that have been reported with infestations include: arborvitae, azalea, boxwood, burning bush, dwarf alberta spruce, hemlock, sunflower, spruce, serviceberry and viburnum just to name a few. Natural control keeps mites in check in the landscape. However, homeowners may want to use one half of the percent of spray of Sunspray oil or similar refined spray oil. Applications must be made weekly. The half percent spray solution works by suffocating the mites. Good spray coverage is essential.
In nurseries, where insecticide use is more prevalent, mites can be a problem because natural enemies are not present. The best products for restoring natural control are Hexygon and Ornamite, because they kill only spider mites and not predator mites and other beneficial insects. If nurseries use either Hexygon or Sanmite, one application usually is all that’s needed. Check treated plants in two weeks. Reapply if needed. Other non-selective miticides that will control mites include: Floramite, Sanmite, Apollo, Shuttle and Kelthane (if available). When using non-selective miticides, check treated plants in five to seven days and reapply if needed according to label directions.