Integrated Pest Management

RED SCALE
HEMIPTERA: DIASPIDIDAE: Aonidiella aurantii

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Identification

Photo

  • only first stage mobile, rest cannot move

  • overwinter on the framework of the citrus tree

  • move to the branches and fruit during the spring and early summer

 

Check Your Diagnosis

  • small brown circular insects

  • minute white dots can sometimes be seen interspersed with the Red Scale (white caps) the crawlers

Photo

 

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Data Sheet

Damage Symptoms

on fruit

PHOTO

on leaves

Photo

on blossom

Photo

on twigs

Photo

1. On Fruit

Feeding damage Want to know more?
Red scale causes cosmetic damage to fruit
  • As the red scale settles on the fruit it leaves a yellow circular mark on the fruit
  • Heavily infested fruit can lead to fruit drop
  • If the scale settles on the fruit within 8 weeks of petalfall, the area around the scale expands slower than the surrounding area causing “pockmarks”
  • Scale settling on mature fruit can cause “speckling” Areas directly around scales can turn yellow, not orange

2. On Leaves

Feeding damage Want to know more?
Scales settle on leaves. Heavy infestations can lead to leaf drop  

3. On Blossoms

NONE

4. On Twigs

Feeding damage Want to know more?
  • Heavily infested trees lead to leaf drop and defoliation
  • In severe infestations it leads to the die back of twigs and branches
It is the feeding juice of red scale that becomes toxic to the tree in large infestation numbers

Life Cycle

Drawing of life cycle
r-strategist:
  • high reproduction (infestation levels rise quickly)
  • low survival (can easily be killed)
  • rebound quickly ( after spraying pest levels can rise fast if all predators are killed)
   
First instar
  • crawler
  • white caps
  • nipple
Crawler: search for a suitable spot / tend to move outwards / settles on upper surface of leaves along midribs and veins
Whitecap: as soon as the crawler has settled, it secretes a white cottony covering.
Nipple: the body becomes circular. It secretes a thin waxy covering at the outer edge, causing the whitecap to lift up.
 
 
second instar No legs visible ( immobile)

Both sexes have a circular shape

Too small for Aphytis africanus to parasitize

Later the male forms a elongated covering

 
gray adult female Both sexes can now be parasitezed by
Aphytis africanus
 
mature adult female Red orange color
Immobile
1-2 mm
Waxy covering enlarge considerably
Fertilization of females
 
reproductive adult female A harder and darker central disk distinguishable  
adult male Elongated cover
A insect with wings are able to fly around to fertilize mature females

Adults overwinter in tree framework

 

Seasonal Cycle in Vaalharts

Graph
  • Multivoltine: 5 generations per year

 

Top Check Your Diagnosis Data Sheet Natural Enemies Management
    DAMAGE SYMPTOMS   MONITOR
    LIFE CYCLE   ECONOMIC THRESHOLD
    SEASONAL CYCLE   CONTROL OPTIONS
        CHECK POINTS

 

Natural Enemies

Photo Photo Photo Photo

 

 

Top Check Your Diagnosis Data Sheet Natural Enemies Management
    DAMAGE SYMPTOMS   MONITOR
    LIFE CYCLE   ECONOMIC THRESHOLD
    SEASONAL CYCLE   CONTROL OPTIONS
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Management

 
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