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Aculus schechtendali (Nalepa)
Insecta, Acari, Eriophyidae .

Apple bud and leaf mite, Apple rust mite

Description, Biology, Life Cycle, Damage, Common Names, Images

- Egg: 0.045 to 0.050 mm diameter, 0.030 mm long; transparent becoming semi-transparent.
- Protonymph: 0.068 to 0.104 mm long, white. prodorsal shield very granular.
- Nymphopupa: white to orange-brown, semitransparent shiny cuticle.
- Deutonymph: very pale orange-brown, 0.104 to 0.124 mm long, granular shield.
- Imagopupa: larger and darker than the nymphopupa.
- Adult: orange-brown, older mites being darker; the male measures 0.142 mm to 0.151 mm and the protogynae 0.166 to 0.181 mm. The dorsal shields of deutogynae are not granular while those of protogynae are, but to a lesser extent than in nymphs.

- Host plants: apple, pear.
- The mites migrate from their hibernation site towards flower buds. They feed firstly upon green scales and the tips of rolled leaves, later colonizing petioles, flower stems and sepals.
- Fruit buds are attacked as soon as they begin to swell and the scales begin to open. Thereafter, the mites develop preferentially on the underside of leaves (*) , but if they are particularly abundant, they may also be found on the upper surface.
- The total fecundity of protogynae is 67 to 102 eggs laid over several days, while deutogynae produce 21 to 47 eggs.
- Deutogynae move to their hibernation site between July and September, depending on the state of foliage. When they hibernate on one-year-old shoots, they are in close proximity to fruit buds which will thus be attacked early. When they hibernate under the bark of spurs, they are further from flower buds which will thus be attacked later.

[R]Life Cycle
- The eggs are laid on the green parts of fruits and on fruit buds. They begin to hatch in May and give rise to a generation of protogynae and males, which are mature from the end of May. Populations grow very slowly during May, then more rapidly as the temperature rises, to reach a peak of more than 500 individuals per leaf by the end of August. In May, the deutogynae die and, for several weeks, the colonies contain only protogynae. At the end of June, deutogynae reappear and their numbers increase until the end of the season.
- Length of cycle = 39 days at 10°C; 16 days at 16°C; 10 days at 22°C.

The underside of heavily infested leaves becomes brown. (*) .

[R]Common Names
DE: Apfelrostmilbe ES: Acaro del ruseting del manzano FR: Phytopte libre du Pommier IT: Eriofide del melo PT: Eriofídeo da macieira GB: Apple bud and leaf mite, Apple rust mite

[R] Images

  1. Aculus schlechentdali (Nalepa) (Cotton D. / INRA Montpellier)
    Damage on epidermis of apple
  2. Aculus schlechtendali (Nalepa) (Cotton D. / INRA Montpellier)
    Individuals on apple

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