Apple-Apple rust mite

Aculus schlechtendali

Pest description and crop damage Extremely small, wedge-shaped mite, which is tan to amber colored. Magnification is required to see this mite. Feeding makes leaves look off-color, sometimes with a silvery sheen. Leaves roll lengthwise. Feeding shuts down terminal growth. Populations of apple rust mite should be tolerated because rust mites are an important alternate food source for predatory mites. However, rust mite can cause russeting on Golden Delicious or other green/fair colored apples and some control may be required for certain apple varieties.

Biology and life history These mites overwinter as adult females under bud scales and in bark crevices. When growth begins they move out onto the leaves to feed, and produce several generations. In late July or early August they return to bud scales and bark crevices to diapause/overwinter.

Management-biological control

Conserve predatory mites, such as Typhlodromus spp., which provide effective control, by avoiding broad-spectrum insecticide applications.

Management-chemical control: HOME USE

Spring and summer (note: treatments rarely necessary)

  • carbaryl-Highly toxic to bees.
  • kaolin clay-Applied as a spray to leaves, stems, and fruit, it acts as a repellant to some insect pests. Some formulations are OMRI-listed for organic use.
  • sulfur-Some formulations are OMRI-listed for organic use.

Management-chemical control: COMMERCIAL USE

Stages 5-6: Pink spray (note: treatments rarely necessary)

  • fenbutatin-oxide (Vendex 50WP) at 1 to 2 lb/a in up to 100 gal water per application. Do not apply more than two times per growing season. REI 2 days. [Group 12B]
  • fenpyroximate (FujiMite 5EC) at 2.0 pints/a in a minimum of 100 gal water per application. Only one application per season. Suppression only. REI 12 hr. [Group 21A]
  • kaolin clay (Surround WP) at 25 to 50 lb/a applied as a spray to leaves, stems, and fruit. Continue applications every 7 to 14 days to assure adequate coverage on newly growing plant surfaces. Kaolin acts as a repellant to target pests. Some formulations are OMRI-listed for organic use. REI 4 hr.
  • pyridaben (Nexter) at 6.6 to 10.67 oz/a in up to 100 gal water per application. Only one application per season. REI 12 hr. [Grp 21A]
  • spirodiclofen (Envidor 2SC) at 16 to 18 oz/a in a minimum of 100 gal water per application. Do not apply more than one application per growing season. REI 12 hr. [Group 23]

Spring and summer (note: treatments rarely necessary)

Also, see control recommendations for pink stage bud development.

  • fenbutatin-oxide (Vendex 50WP) at 1 to 2 lb/a in up to 100 gal water per application. Do not apply more than two times per growing season. REI 2 days. PHI 14 days. [Group 12B]
  • pyridaben (Nexter) at 6.6 to 10.67 oz/a in up to 100 gal water per application. Apply as populations begin to build, between petal fall and harvest. Do not exceed one application per season. REI 12 hr. PHI 25 days. [Group 21A]
  • spirodiclofen (Envidor 2SC) at 16 to 18 oz/a in a minimum of 100 gal water per application. Do not apply more than one application per growing season. REI 12 hr. PHI 7 days. [Group 23]
  • spirotetramat (Movento) at 6 to 9 fl oz/a in up to 100 gal water per application. Do not exceed 25 fl oz/a per growing season. Do not apply until after petal fall. REI 24 hr. PHI 7 days. [Group 23].