Integrated Pest Management

Thrips
THYSANOPTERA: THRIPIDAE: Scriptothrips aurantii (Faure)

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Identification

Photo

 

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Minute yellow elongated bodies

Moves fast on the fruit surface

Photo

Citrus thrips is very fruit specific.

Other thrip species are also present on the citrus tree, but they do not damage the fruit

e.g. flower thrips present when the blossoms are present and onion thrips always present

 

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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?

Feeding dulls the glossy look of the fruitlets

Damage early in the season is a ringshaped scar around the calyx

polyphagous

sucking mouthparts with which the sap is drawn from the cells

feeding causes permanent damage to fruit

superficial scarring – it turns silvery white later

2. On Leaves

Feeding damage

Want to know more?

Leaf damage is a parallel line on each side of the midrib, causing the leaf to turn upwards at the tip

Thrips feeds on the young leaves later in the season when the fruit has hardened

Severe leaf damage can lead to crop losses in the following season

3. On Blossoms

Feeds on buds, new growth and fruitlets

Flower thrips are present when the blossoms are present, but not damaging to fruit

4. On Twigs

NONE

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)

    

Egg

Invisible to the naked eye

 

Larvae

At maturity they drop to the ground after sunset and pupate beneath the citrus trees

Most larvae drop close to the trunk

Pupa

Non feeding stage

Molting in the soil

Moulting takes place within the soil or leaf litter

adult

  • Pale, orange yellow

  • Wings are folded longitudinally over the body when at rest

  • Fringed wings

  • Regular markings on the abdomen consist of darkened anticostal ridges and patches

  • Sucking mouthparts

  • Tarsi(feet) end in a bladderlike shape

Emergence of adults coincides with the hardening off of the spring flush at the end of blossoming.

The adults then infest the small fruitlets

Seasonal Cycle in Vaalharts

Graph

Two peaks in the population of thrips in a season.
Peak 1: December
Peak 2: February

Multivoltine : many generations per year
 

 

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Natural Enemies

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Management

 
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