Dasineura crataegi

'Dasineura crataegi'
Button-top gall on Hawthorn
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Family: Cecidomyiidae
Genus: Dasineura
Species: D. crataegi
Binomial name
Dasineura crataegi
(Winnertz, 1853)

The hawthorn button-top gall, is caused by the dipteron gall-midge Dasineura crataegi (Winnertz, 1853). The gall develops in the terminal shoots of Hawthorn, Crataegus monogyna (Jacq.) and the midland hawthorn Crataegus laevigata (Poir.) and their hybrids.[1][2]

Synonyms are Perrisia crataegi and Cecidomyia crataegi, (Winnertz, 1853).[3]

The physical appearance of the galls

Dissected terminal bud showing ligulate excresences.

The gall causer induces stunted and distorted rosettes[4] in the host by inhibiting the elongation of the shoot; the rosette is formed from many (8 to 40 or more) slightly thickened and deformed leaves with reduced petioles. Many of the leaves have small green or red ligulate excrescences or projections. The midge larvae are of an orange-red colour.[1][2]

The gall is occasionally found on isolated shrubs, however hedges are more commonly infested with the new growth resulting from hedge cutting of being the site of high density populations. The rosettes stand out prominently against the sky. Old galls persist and new elongations of the branch occurs from unaffected buds lying well behind the terminal bud.[3]

Life-cycle

Rosette gall with normal growth arising from a side bud.

Adults emerge from pupae in the ground beneath the shrub and the terminal bud infestations start in March or April; the fully grown larvae fall to the ground in September or October to undergo pupation after feeding and sheltering within the leaf rosette for some time.[3]

Distribution and control

The nettle pouch gall shows a scattered distribution throughout England, however it is an under recorded species.[5] The gall can be controlled by spraying with insecticide at the larval stage.[6]

Parasitoids

Aprostocetus lysippe is a hymenopteran insects of the family Eulophidae and a parasitoid of D. crataegi.

See also

References

Notes
  1. 1 2 Stubbs, Page 23
  2. 1 2 Redfern, Page 315
  3. 1 2 3 Darlington, Page 137
  4. Hancy, Page 88
  5. NBN Gateway
  6. Pest & Diseases. Accessed : 2010-08-26
Sources

External links

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