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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Deciduous > Hawthorn > Dots, spots or blotches on leaves

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Hawthorn > Leaves > Dots, spots or blotches on leaves

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  • Image: Apple Scab 1
  • Image: Apple Scab 2
  • Image: Apple Scab 3

Cedar-hawthorn rust
Gymnosporangium globosum

  • Yellow to orange spots on leaves
  • Leaves may turn bright yellow and drop
  • White, tubular fungal spore producing structures up to ½ inch long form on lower surface of leaf spots
  • Can infect and deform fruit and green stems
  • More information on Cedar-hawthorn rust…
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  • Image: Apple Maggot 1
  • Image: Apple Maggot 2
  • Image: Apple Maggot 3

Powdery mildew
Podosphaera spp. and Phyllactinia guttata

  • White-grey, felt-like spots or patches on leaves
  • Infected leaves may curl, twist or fold upwards
  • Infected blossoms are distorted, discolored and covered in white powdery fungal growth
  • Lower shaded leaves and small, understory trees are most commonly affected
  • More information on Powdery mildew...
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  • Image: Plum Curculio 1
  • Image: Plum Curculio 2
  • Image: Plum Curculio 3

Pear sawfly
Caliroa cerasi

  • Larvae "windowpane" feed i.e. eat upper leaf surface but leave veins
  • Heavy feeding gives tree a scorched appearance
  • Premature leaf drop
  • Larvae are about ½ inch long, shiny, slug-like, initially dark green to black
  • More information on Pear sawfly...
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  • Image: Apple Curculio 1
  • Image: Apple Curculio 2
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Hawthorn leafminer
Profenusa canadensis

  • Larvae feed between leaf surfaces causing translucent spots or blotches on leaves primarily on the leaf tips
  • Injured areas turn brown; from a distance, foliage appears scorched
  • Frass (droppings) noticeable, especially when leaf held up to a light
  • More information on Hawthorn leafminer...
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  • Image: Tarnished Plant Bug 1
  • Image: Tarnished Plant Bug 2
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Hawthorn lace bug
Corythucha cydoniae

  • Pinprick whitish to yellow-brown discoloration on upper surface
  • Persistent feeding can cause damaged areas to coalesce into blotches
  • Black dots or specks (droppings) on underside of leaves
  • Heavy feeding can cause leaf drop
  • Damage is most notable mid to late summer
  • Adults are about 1/8" long, light brown bodies with intricate, lacy wings
  • More information on Hawthorn lacebug...

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