Spider mites can affect a wide variety of crops, including many stone fruit trees such as cherries, peaches, plums, nectarines and others. Two-spotted spider mites and Pacific mites are two common species of web-spinning mites. European Red Mite can also be found on stone fruit in some regions. Pacific spider mite female adults can vary from orange-red in color to slightly green, typically turning red or orange later in the season. Two large spots on the front of the mites and two smaller spots on the rear portion of the abdomen appear once feeding has begun.

The two-spotted spider mite is distinguished by having only the two pronounced dark spots on the front part of its body, with no spots on the rear. Adult females for these two species overwinter in tree bark and emerge in spring when they begin feeding and reproducing.

Adult female European red mites appear red with long hairs that arise from white spots on the mites’ backs. Nymphs are typically green in color. Their eggs are red and slightly flattened. European Red Mite overwinter in eggs.

Spider mites feed on leaves through piercing-sucking mouth parts. This causes leaves to turn yellow and eventually die off and fall. Webbing is usually present in more severe infestations. Spider mites damaging leaves can result in yield and quality damage, sometimes in the year following the infestation.

Spider Mite Management on Stone Fruit

Natural predators are an important factor in keeping spider mite populations from growing out of control. Broad pesticides should be avoided, as they can harm natural predators, resulting in spider mite outbreaks. Commercially reared predators are available for release. The Western Predatory Mite (Galendromus occidentalis) or Neoseiulus californicus are able to control less severe spider mite infestations in most cases, without any pesticides needed. Predatory mites should be release in areas of the orchard where higher spider mites populations have been scouted. Multiple releases may be necessary to establish predator populations.

Cultural control aspects are also important for spider mites. Controlling dust, by applying water to roads and furrows can be helpful. Avoiding water stress on trees is also very important, because spider mites establish infestations faster on water stressed trees.

If chemical control is needed for severe infestations, be very careful to check the label of available products. Different active ingredients of miticides can be used to target different life cycles of spider mites. Different products will also affect other insects, such as natural predators, in different ways.

Learn more: Complete Guide to Spider Mites