Whiteflies in Ornamentals.pdf

Agricultural Extension Service

The University of Tennessee

SP290-R

Whiteflies on Ornamentals

Frank A. Hale, Professor

Originally developed by Jaime Yanes, Jr., former Assistant Professor

and Harry E. Williams, Professor Emeritus

Entomology and Plant Pathology

Whitelies are economically important insects on orna-

mentals grown in the greenhouse. Although these pests are

most serious in the greenhouse, whitelies may also attack

ornamental plants grown outdoors. Some of the preferred

woody ornamental hosts include barberry, redbud, Fucshia ,

honeylocust, black locust, Hibiscus, Lantana , coffeeberry,

rose and Jerusalem cherry.

Description and Life Cycle

Adult whitelies vary in size from 1 to 3mm. Their

wings are generally covered with a powdery substance, giv-

ing them the appearance of tiny white moths. Adult females

lay eggs on the lower leaf surface of plants. Their oblong

eggs vary from yellow to pale green to purple. Some species

(the greenhouse whitely in particular) lay their eggs in a

characteristic circle or semi-circle. Each female may lay up

to 400 eggs and live as long as two months. Eggs require

one to three weeks to hatch.

After hatching, young nymphs (immatures) crawl about

the plant for a few days, then settle down to feed. At this

point, they insert their mouthparts into the plant tissue to

feed. They then remain motionless until maturity. Nymphs

are lattened and scale-like in appearance. A fringe of waxy

material radiates outward from their bodies. This fringe is

made of thick waxy plates or ine strands, depending on the

species. The nymphal stage requires three to four weeks

before pupation.

Life cycle of the greenhouse white ly. A, Adult. B, Eggs. C-E,

Nymphs. F, Pupa.

The pupa may be darkened (parasitized) or white,

often with a fringe of long hairs on its back. The newly

emerged adult whitely is whitish yellow. It shortly be-

comes covered with a white, powdery material.

Whitelies reproduce very slowly (about one genera-

tion per month). Whitelies in all stages of development

may be seen in infested plants. Several generations may

occur each year.

The removal of sap by this pest results in yellow-

ing and drying of the foliage. While feeding, whitelies

excrete honeydew ( a sweet sticky substance). Sooty mold

fungi growing on the honeydew detracts from the ap-

pearance of the plant.

Control

Eggs and immature stages are resistant to many insec-

ticides. Thus, whitely control is dificult. Insect growth

regulators such as kinoprene, azadiractin, dilubenzuron,

pyriproxyfen and fenoxycarb should be used to aid in con-

trol of the immature stages. The other listed insecticides

should be used to target both immatures and adults. Use

both insect growth regulators and conventional insec-

ticides for best control. Start chemical control early before

populations build, using alternate sprays of insect growth

regulators, insecticidal soap and horticultural oil. If adult

populations are increasing, use one of the other insec-

ticides to reduce the adult whitely population.

Interior plantscapes such as in hotels, shopping malls,

ofice buildings, etc: horticultural oil (SunSpray Ultra-Fine

Oil), insecticidal soap (Safer Insecticidal Soap, M-Pede),

luvalinate (Mavrik Aqualow 22.3F), cyluthrin (Tempo

20 WP, Decathlon 20 WP), beta-cyluthrin (Tempo SC

Ultra 1 SC), pyrethrins plus piperonyl butoxide (Pyre-

none, Natural Pyrethrin Concentrate, PT 1600 X-clude A),

permethrin (Astro 36.8 EC), imidacloprid (Merit 75 WP,

Merit 2F,Marathon II 2F), kinoprene (Enstar II), or azadi-

rachtin (Safer Bioneem, Azatin XL, Ornazin 3% EC).

Home use indoors: azadirachtin (Safer Bioneem),

insecticidal soap (Safer Insecticidal Soap), horticultural

oil (SunSpray Ultra-Fine Oil), or pyrethrins plus piperonyl

butoxide (Pyrenone, PT 1600 X-clude A).

Outdoors use: bifenthrin (Talstar Lawn and Tree 7.9

F), luvalinate (Mavrik Aqualow 22.3 F), endosulfan

(Thiodan 50 WP, Thiodan 3 EC), acephate (Orthene Turf,

Tree and Ornamental Spray 75 SP, Address T/O 75 SP),

cyluthrin (Advanced Garden Lawn and Garden Multi-

Insect Killer, Tempo 20 WP, outdoor use of Decathlon

20 WP designated for nurseries), beta-cyluthrin (Tempo

SC Ultra 1 SC), permethrin (Astro 36.8 EC), insecticidal

soap (Safer Insecticidal Soap, M-Pede), horticultural

oil (SunSpray Ultra-Fine Oil), pyrethrins plus piperonyl

butoxide (Pyrenone), imidacloprid (Merit 75 WP, Merit

2 F, Marathon 60 WP, Advanced Garden Tree and Shrub

Insect Control, Marathon II 2F), imidacloprid plus cylu-

thrin (Advanced Garden Rose and Flower Insect Killer),

disulfoton plus 12-18-6 fertilizer (Advanced Garden 2-in-1

systemic Rose and Flower Care), abamectin (Avid 0.15 EC),

or azadirachtin (Azatin XL, Safer Bioneem, Ornazin 3% EC).

Follow label directions carefully. Repeat sprays every

four to ive days until whitelies are under control. Do not use

horticultural oil more than once per week.

Chemical Controls

Greenhouse use: bifenthrin (Talstar GH 7.9 F, PT

Attain TR 0.5A), luvalinate (Mavrik Aqualow 22.3 F),

permethrin (Astro 36.8 EC), endosulfan (Thiodan 50 WP,

Thiodan 3 EC), naled (Dibrom 8E), acephate (Orthene

Turf, Tree and Ornamental Spray 75 SP, Address T/O 75

SP, PT 1300 Orthene TR 12 A), cyluthrin (Decathlon 20

WP), chlorpyrifos plus cyluthrin (PT Duraplex TR 8 A),

pyrethrins plus piperonyl butoxide (Pyrenone, PT 1100

Pyrethrum TR, Natural Pyrethrin Concentrate), imidaclo-

prid (Marathon 1% Granular, Marathon 60 WP, Marathon

II 2F), horticultural oil (SunSpray Ultra-Fine Oil 98.8 EC

[Use a 0.5-1% spray solution]), insecticidal soap (M-Pede),

abamectin (Avid 0.15 EC), kinoprene (Enstar II), fenoxy-

carb (PT Preclude TR 4.8 A, Precision 25 WP), azadi-

rachtin (Ornazin 3% EC, Azatin XL), pyridaben (Sanmite

75 WSB), dilubenzuron (Adept 25 WSP), pymetrozine

(Endeavor 50 WDG), pyriproxyfen (DISTANCE 0.86 EC)

or lambda-cyhalothrin (Scimitar GC 9.7 ME).

Precautionary Statement

To protect people and the environment, pesticides should be used safely. This is everyoneʼs responsibility, especially the user. Read and follow label

directions carefully before you buy, mix, apply, store or dispose of a pesticide. According to laws regulating pesticides, they must be used only as directed

by the label. Persons who do not obey the law will be subject to penalties.

Disclaimer Statement

Pesticides recommended in this publication were registered for the prescribed uses when printed. Pesticide registrations are continuously reviewed.

Should registration of a recommended pesticide be canceled, it would no longer be recommended by The University of Tennessee.

Use of trade or brand names in this publication is for clarity and information; it does not imply approval of the product to the exclusion of others that

may be of similar, suitable composition, nor does it guarantee or warrant the standard of the product.

The Agricultural Extension Service offers its programs to all eligible persons regardless of race,

color, national origin, sex, age, disability, religion or veteran status and is an Equal Opportunity Employer.

COOPERATIVE EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS

The University of Tennessee Institute of Agriculture, U.S. Department of Agriculture,

and county governments cooperating in furtherance of Acts of May 8 and June 30, 1914.

Agricultural Extension Service

Charles L. Norman, Dean

04-0008-SP290R-1M-9/03(Rev) E12-4615-00-003-04

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