The European red mite is a species of spider mite. It is not an insect, but an insect relative worthy of mention in this guide. It is found throughout much of the Northeast and primarily on plants in the Rosaceae family, but may be found on fruit and shade trees and shrubs worldwide. It is a European species that was introduced into the United States in the early 1900's. It can have as many as seven generations per year (as observed in New York orchards); however points south report 8-10 generations per year. Eggs of this species are different in appearance/location on the host plant depending upon the time of year. In the summer, eggs are laid on the leaves of the host plant and are translucent yellow and spherical. Overwintering eggs are bright red and possess a white stalk that is visible with magnification. Overwintering eggs are typically laid in the cracks and crevices of host plant bark. Eggs are approximately 1/200th of an inch. Overwintering eggs may be present in the tens of thousands on apple trees. Egg hatch is reported in late April in New York, or just prior to bloom in other parts of its introduced range. Mites will migrate to the leaves to feed. Each female is said to lay a single egg per day. Egg laying continues through the subsequent generations and mites pass through egg, immature (6 legs and then 8 legs), and adult (8 legs) stages. All are described as brick red in color. European red mite numbers increase as the season progresses, and may become unacceptably high if favorable hot, dry summer conditions are experienced.
European red mites feed on the leaves of their host plants, removing plant fluid from individual plant cells. When infestations are large, leaves become "bronzed" or discolored, typically by mid-July. In orchards, fewer fruit, dropped fruit, or lower fruit quality are reported. In some cases, fewer buds for the next season's crop have been reported in apple. The time of year, duration of feeding, site conditions, and abiotic conditions can influence the severity of the impact of this pest. In managed landscapes, European red mite activity is primarily an aesthetic issue.
Scouting can occur weekly from just after apple petal fall until approximately August, or until populations are below 10 mites per leaf after August 1. Samples can be taken from at least 4 leaves per tree, at different sides and heights or exterior vs. interior of the tree. View these leaves with at least a 10X hand lens and look for mites on the undersides of leaves. Certain thresholds exist for management in fruit orchards, depending upon the time of year the samples are taken. Finding 1 mite per leaf may result in 40% of leaves being impacted. Finding 3 mites per leaf may result in 75% of the leaves being impacted.
Tolerate European red mite activity whenever possible in ornamental landscapes, as many effective predators and natural enemies typically reduce their populations. Choosing reduced risk pesticides when managing European red mite or other pests on these hosts will help preserve natural enemy populations which are very important in managed landscapes.
A mite predator, lady beetles, and lacewings are all noted to be significant natural enemies of this spider mite pest. Orius insidiosus, Stethorus punctum, Amblyseius fallacis, Agistemis fleschneri, and Zetzellia mali are all predators of the European red mite that have been reported in the US. Many are negatively impacted by chemical management of the European red mite, so limit chemical applications to reduced risk options only to preserve natural enemy populations that are very important in regulating the populations of this introduced spider mite.
Abamectin (NL)
Acequinocyl (NL)
Bifenazate (NL)
Bifenthrin (NL)
Chlorpyrifos (N)
Chromobacterium subtsugae (NL)
Cyflumetofen (NL)
Etoxazole (N)
Fenpropathrin (NL)
Tau-Fluvalinate (NL)
Hexythiazox (NL)
Horticultural Oil (L)
Insecticidal soap (NL)
Lambda-cyhalothrin (L)
Malathion (L)
Metarhizium anisopliae (robertii) (NL)
Neem oil (NL)
Pyridaben (NL)
Spiromesifen (L)
Orchard fruit trees (apple, plum, cherry, etc.) are the most seriously impacted. Management information for orchard settings is not provided here. This information is gathered for ornamental plants growing in managed landscapes and should not be used for orchard management.
Active ingredients that may be applied systemically include: abamectin (injection), Metarhizium anisopliae (robertii) (soil drench), and neem oil (soil drench).
Make insecticide applications after bloom to protect pollinators. Applications at times of the day and temperatures when pollinators are less likely to be active can also reduce the risk of impacting their populations.
Note: Beginning July 1, 2022, neonicotinoid insecticides are classified as state restricted use for use on tree and shrub insect pests in Massachusetts. For more information, visit the MA Department of Agricultural Resources Pesticide Program.
