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Chrysomphalus dictyospermi Morgan
Insecta, Homoptera, Diaspididae .

Palm scale

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


[R]Description
- Adult: the female scale is almost circular, diameter between 1.8 and 2.1 mm. Nymphal exuviae are slightly excentric; their edges appear as brown on the ocrous background of the scale. The body of the scale insect is yellow. The female is oviparous (*) .
The male possesses one pair of whitish wings; the body is yellowish. Dimensions: 1 mm long, 1.5 mm wide. Legs, antennae and external genitalia are blackish-brown.
- Eggs: golden yellow, laid under the scale.
- Nymph: newly emerged first-stage nymphs are mobile. They disperse on the plant and then settle.

[R]Biology
- The palm scale is polyphagous. It infests olive, Citrus, fig, avocado (Persea americana) and palm (Phoenix), etc.
This species overwinters as young females and N2 nymphs. These individuals lay their eggs in March-April, thus producing the first generation.
Each female lays 100 to 150 eggs in the spring over a period of about 40 days, while in the summer this period only lasts 26 days.
Embryonic development preceeds laying, the egg hatching 1 to at most 24 hours afterwards.
The mobile nymph settles in less than 24 hours; it undergoes its first moult 8 days later. The second and last nymphal instar lasts about 13 days.
A further 23 days is necessary for the female to be capable of laying eggs. Males take longer to become sexually mature and thus the first egg is laid only after 44 days.

[R]Life Cycle
- 3 generations usually occur each year. A fourth may occur under certain climatic conditions (warm autumn), but these individuals have difficulty in surviving the winter.
- The first spring-time generation is followed by a second in June, while the third does not appear before the end of August.
- As in many Diaspididae, generations overlap and it is the periods of emergence of mobile nymphs which are recorded.

[R]Damage
Mobile nymphs settle in the spring on the upper surface of old leaves, and later, on new shoots and young fruits. The area around the scale insects then goes yellow because of their feeding activities.
Heavily infested leaves (*) dry up and fall. Branches wilt. Infested fruits are deformed (*) . Finally, sooty moulds are seen, developing on the honeydew.


[R]Common Names
DE: Rote Orangenlaus ES: Cochinilla roja del naranjo FR: Pou rouge des orangers IT: Cocciniglia Bianca-rossa degli agrumi PT: Pinta amarela, Cochonilha dourada da laranjeira GB: Palm scale

[R] Images

  1. Chrysomphalus dictyospermi (Morgan) Colony (Bernard J.-F. / INRA Maroc)
  2. Chrysomphalus dictyospermi (Morgan) Coated leaves (Bernard J.-F. / INRA Maroc)
  3. Chrysomphalus dictyospermi (Morgan) Damage to fruit (Bernard J.-F. / INRA Maroc)

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