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Topic

“Bemisia tabaci (sweetpotato whitefly)”

Contents:-• Introduction• Distribution • Importance • Appearance • Life cycle

Introduction

Scientific classification

Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Hemiptera

Suborder: Sternorrhyncha

Family: Aleyrodidae

Genus: Bemisia

Distribution• Found in worldwide in

tropical, subtropical, and less predominately in temperate habitats.

• Firstly discovered in 1894.• Found from Florida to

California in United State.• Commonly known as

sweetpotato whitefly

﴿ Two sweetpotato whitefly biocomplex exist

i. Cotton strain ii. Poinsettia strain﴿ Poinsetta strain is first

discovered in Florida greenhouses in 1986, then on fields crops in 1987, spread to Arizona b/w 1988 and 1990.

﴿ Sweetpotato whitefly nymph suck plan sap & excrete covering of sticky honeydew.

﴿ They transmit viruses, including lettuce fectious yellows and squash silver leaf.

﴿ Host ant of this insect may more than 400 sp.

﴿ Can cause severe damage to melons, alfalfa, cotton, early-planted lettuce,cauliflower,broccoli and eggplant.

﴿ Can cause moderate demage in citrus, grapes, lettus, sugarpeets, tomatoes and green beas.

﴿ In california, Annual losses is more than 100 million during severe outbreaks.

Appearance۞Four-winged insect

۞1.5-2.0 mm long۞Resemble like tiny moths۞White dust or dusty

powder covers the wings۞Immature appears

tranparent oval forms, latter developing two yellow spots about 1/3 of way along the body.

۞Eggs are oval shaped ۞Arranged in semicircle

underside of leaves.۞Pupae are opaque yellow ۞Adult resembles that of

greenhouse whitefly but having yellow body color

۞Greenhouse whitefly have white body color

Life Cycle₪The development time

range from 15-70 days, dependent upon temperature and plant host.

₪Have following stages:a) Eggs b) Nymphs c) Adults

Eggs Females lay from 28-300

eggs depending on host and temperature.

Egg densities can be as high as 1,200 eggs per square inch.

On cotton, a female lays 81 eggs, on average

NymphsThe first nymphal stage is

called crawlerlast stage is often referred to

as the pupa.After hatching the crawlers

move a short distance and settle to feed.

Nymphs are creamy white to light green and oval in outline

nymphal period lasts about 2-4 weeks

AdultsAdults live b/w 8 and 12

days, depending upon temp.

In California, overwinters on desert weeds, colonizes in January and February.

Then migrates to cotton in April and May.