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Dahlia

Dahlia
Genus:Dahlia
Family:Asteraceae
Type:Tender perennials
Pollination:Insect

Dahlia is a genus of bushy, summer- and autumn-flowering, tuberous perennials that are originally from Mexico, where they are the national flower.

Description

In 1872 a box of Dahlia roots were sent from Mexico to the Netherlands. Only one plant survived the trip, but produced spectacular red flowers with pointed petals. Nurserymen bred from this plant, which was named Dahlia juarezii with parents of Dahlias discovered earlier and these are the progenitors of all modern Dahlia hybrids. Ever since, plant breeders have been actively breeding Dahlias to produce thousands of cultivars, usually chosen for their stunning and brightly coloured flowers. Dahlia plants range in height from as low as 12" (30 cm) to as tall as 6–8 feet (180–240 cm). The flowers can be as small as 2" (5 cm) or up to a foot (30 cm) in diameter. The great variety results from Dahlias being octoploids (they have eight sets of homologous chromosomes, whereas most plants have only two).

Growing conditions

Varieties

Uses

Maintenance

Propagation

Harvesting

Pests and diseases

Dahlias are used as food plants by the larvae of some Lepidoptera species including Angle Shades, Common Swift, Ghost Moth and Large Yellow Underwing. Crown Gall

  • Agrobacterium tumeifasciens

Wilt

  • Pseudomonas solanacearum

Rot (Bacteriosis)

  • Erwinnia carotovora

Powdery Mildew

  • Erysiphe cichoracearum
  • Erysiphe polygoni

Leaf Spots

Gray Mold

Blight

  • Botrytis cinerea

Wilts

  • Fusarium
  • Verticillium albo-atrum

Stem Rots

  • Pellicularia filamentosa
  • Pellicularia rolfsii
  • Pythium debaryanum
  • Pythium oedochilum
  • Pythium ultimum
  • Sclerotinia sclerotiorum

Soft Rots

Smuts

  • Entyloma dahliae: Dahlia Smut

Viruses

  • Impatiens Necrotic Spot Virus
  • Tomato Spotted Wilt Virus
  • Cucumber Mosaic Virus
  • Dahlia Mosaic Virus

Nematodes

  • Meliodgyne haple
  • Meliodgyne incognita
  • Potato Rot Nematode: Ditylenchus destructor:

Aphids

  • Buckthorn Aphid: Aphis nasturtii
  • Bean Aphid: Aphis fabae
  • Foxglove Aphid: Acyrthosiphon solani
  • Green Peach Aphid: Myzus persicae
  • Leaf Curling Plum Aphid: Brachycaudus helichrysi
  • Melon Aphid: Aphis gossypii

Hoppers

  • Rose Leafhopper: Edwardsiana rosa
  • Leafhopper: Empoascus fabae
  • Treehopper: 'Entylia carinata
  • Potato Leafhopper: Empoasca fabae

Mealybugs

  • Citrus Mealybug: Planococcus citri

Whiteflies

Bugs

Earwigs

  • European Earwig: Forficula auricularia

Thrips

  • Greenhouse Thrips: Heliothrips haemorrhoidalis
  • Flower Thrips: Frankliniella thricti
  • Tobacco Thrips: Frankliniella fusca
  • Onion Thrips: Thrips tabaci

Beetles

  • Blister Beetles: Epicauta spp.:
  • Spotted Cucumber Beetle: Diabrotica undecimipunctata
  • Japanese Beetle: Popillia japonica
  • Oriental Beetle: Exomala orientalis
  • Rose Chafer: Macrodactylus subspinosus

Caterpillars

  • Burdock Borer: Papaipema arctivorens
  • Corn Earworm: Heliothis zea
  • European Corn Borer: Ostrinia nubilalis
  • Greenhouse Leaf Tier: Udea rubigalis
  • Saddleback Caterpillar: Sibine stimulea
  • Stalk Borer: Papaipema nebris

Wasps

  • Giant Hornet: Vespa crabro germana

Mites

  • Broad Mite: Polyphagotarsonemus latus
  • Bulb Mite: Rhizoglyphus echinopus
  • Cyclamen Mite: Steneotarsonemus pallidus
  • Two-Spotted Spider Mite: Tetranychus urticae

Slugs

References

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