Brown mite (Bryobia rubrioculus)
European red mite (Panonychus ulmi)
McDaniel mite (Tetranychus mcdanieli)
Twospotted spider mite (Tetranychus urticae)
Yellow spider mite (Eotetranychus carpini borealis)
For mite identification, see:
Pest description and crop damage All adult mites are small, usually only about 0.02" long and have eight legs. The various pear-infesting species vary in appearance as follows:
Brown mite: The adult female is a dull reddish brown with dark orange markings, and somewhat flattened. The front legs are very long, over twice the length of the other legs, and extend forward from the body.
European red mite: Adults are globular, reddish with white spines. Immatures are similar in appearance, only smaller. Eggs are red, globular and have a stripe.
Twospotted or McDaniel mite: Adults are yellowish-brown, about 0.02" long. Twospotted mites have two dark spots on the body, while McDaniel mites have four. Immatures are similar in appearance, only smaller. Eggs are round and translucent to opaque
Yellow spider mite: Adult females are pale yellow to white with 2 or 3 dark, rectangular markings on each side of the abdomen. Immatures are similar in appearance to the twospotted spider mite, but have more of a yellowish color. Eggs are clear and spherical.
Spider mites damage leaves by puncturing cells and sucking out the contents resulting in foliar injury varying from leaf yellowing and stippling to bronzing and blackening. High populations of spider mites can cause significant defoliation.
Biology and life history Twospotted, McDaniel and yellow spider mites overwinter as fertilized females under bark or in soil debris. European red mite and brown mites overwinter as eggs in crevices of twig bark and young limbs. They move to young foliage when buds break in spring and produce many generations during spring to autumn. Females can lay up to 10 eggs per day and more than 200 during their lifetime. Egg-to-adult development can occur in 7 to 10 days during summer. They thrive under hot, dry conditions. Large colonies of mites produce webbing. Dispersal occurs mainly through wind transport via ballooning on their webbing.
Scouting and thresholds Economic damage can occur at levels below 1 mite per leaf in sensitive varieties such as Anjou and Bosc. When spider populations are moderate (< 3 mites per leaf) the presence of predatory mites may allow for treatment to be delayed, but the spider mite population must then be reevaluated frequently to ensure that damaging levels of spider mites do not persist.
Spider mite populations are held down by cool, wet conditions early in the season. Natural enemies, particularly lady beetles (Stethorus spp.), minute pirate bugs (Orius spp.), and predator mites such as Typhlodromus spp. or Neoseiulus fallacis (syn. Amblyseius fallacis) can provide some natural control. However, due to the sensitivity of many pear varieties to spider mite feeding, the effect of natural enemies can be too slow or insufficient to prevent significant damage to foliage.
Spider mite infestations are favored by dry, dusty conditions, so avoid creating these problems and stressing the plants. The use of cover crops also reduces dust and mite problems. Broadleaf weeds like mallow, bindweed, white clover, and knotweed enhance mite numbers. Suppression of these weeds with cultivation or a grass groundcover may reduce mite numbers. Mites may be washed from the tree with a strong stream of water. Water trees properly, as drought-stressed trees are more susceptible. Avoid excessive nitrogen applications, as this encourages mites
Management-chemical control: HOME USE
- lime sulfur
- superior-type oil-Effective only against red mite. Apply at green to tight cluster stage.
- azadirachtin (neem oil)-Products containing neem extract may be phytotoxic to some pear cultivars.
- insecticidal soap
Management-chemical control: COMMERCIAL USE
- horticultural mineral oil at 1 to 2 gal/100 gal water (4 to 8 gal/a)
Growing season spray:
- abamectin (Agri-Mek 0.15 EC) at 10 to 20 oz/a. PHI 28 days. Use an adjuvant; see label. Ground application only. Do not exceed two applications per season. Effectiveness may be limited with late season applications.
- acequinocyl (Kanemite 15SC) at 31 oz/a. PHI 14 days. Do not exceed two applications per season.
- bifenazate (Acramite 50WS) at 0.75 to 1 lb/a. PHI 7 days.
- clofentezine (Apollo SC) at 4 to 8 oz/a. PHI 21 days. Do not exceed one application of Apollo or Savey/Onager per season. Will not control adults. Combine with adulticide if adults are present. This product is not currently registered for use in Idaho.
- dicofol (Kelthane 50WSP) at 4 to 6 lb/a. PHI 7 days. Do not exceed two applications per season.
- etoxazole (Zeal) at 2 to 3 oz/a. PHI 14 days. Use higher rates to control twospotted or McDaniel mites and lower rates to control European red mite. Do not exceed one application per season.
- fenbutatin-oxide (Vendex 50WP) at 1 to 3 lb/a. PHI 14 days. Do not exceed three applications between petal fall and harvest. Not effective in some areas of Oregon because of resistance development.
- fenpyroximate (FujiMite 5EC) at 2 pints/a. PHI 14 days.
- hexythiazox (Savey 50DF) at 4 to 6 oz/a. PHI 28 days. Do not exceed one application of Apollo or Savey/Onager per season. Will not control adults. Combine with adulticide if adults are present.
- hexythiazox (Onager 1EC) at 16 to 24 oz/a. PHI 28 days. Do not exceed one application of Apollo or Savey/Onager per season. Will not control adults. Combine with adulticide if adults are present.
- oxamyl (Vydate L) at 3 to 4 quarts/a. PHI 14 days. Most effective against twospotted and McDaniel spider mites. Vydate is very toxic to predatory mites.
- pyridaben (Nexter 75WP) at 8.8 to 10.67 oz/a. PHI 7 days. Apply before populations begin to build. Use higher rates to control twospotted or McDaniel spider mites and lower rates to control European red mite. Registered SLN label for use in Washington (24c SLN WA090017b) at 10.67 to 16 oz/a. PHI 28 days. Do not exceed one application per season.
- spirodiclofen (Envidor 2SC) at 18 oz/a. Do not exceed one application per season.
Resistance management Spider mites can develop resistance rapidly to chemical controls. Alternate chemistries and modes of action.