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Gulf Coast Station Mimeo Report 57-3
Bradenton, Florida

INSECT AND OTHTrR PESTS OF CHRYSANTHEMTIMS

E. G. Kelsheimer

Introduction

The chrysanthemum industry in Florida has become one of the major flower

.rorducing groups. YMany of the gladiolus growers have a few acres as an added en-

;. ;vor. The flowering schedule is from November to June, although a few grow

hprougho't the year. According to Smith and Brooke (4), of the 233 acres of chrys-

nnthemums grown in the 1959-56 season, 222 are in pompons and 11 acres in standard's

Slightly more then half the acreage is under shade, the remainder in the open.

Th:e writer was first introduced to outdoor culture of murs in 1945 at Br'd-

onton. From that time on a list of insects has been assembled with their control

measuress .

No chrysanthemum grower can hope to grow a crop and escape the attack frc"!

insects and mites, hence his rigid control program (1,2,3). Because of his sprP'

program a good share of the enemies described are ever given a second thought-

However, the home owner, who grows a few for his own enjoyment may during the y-i:-

hive had all of the insect pests herein described. NIums are subject to heavy dam-

age by a few serious pests but specific measures, both preventitive and control

give satisfactory results.

Sucking Insects

Aphis

Description of destructive stage. -- Actual size 1/16 inch. There may be many spe-

cies of aphis that attack mums but we have two that are pests, the melon aphis, A-

phis gossPii (Glover) and the chrysanthemum aphis, Macrosiphoniella eanborn'

(Gill.). They are soft bodied plant bugs, pale green to dark red or nearly black

in color. They may be winged or wingless, generally the latter,
I

Gulf Coast Station Mimeo Report 57-3
Bradenton, Florida

INSECT AND OTHTrR PESTS OF CHRYSANTHEMTIMS

E. G. Kelsheimer

Introduction

The chrysanthemum industry in Florida has become one of the major flower

.rorducing groups. YMany of the gladiolus growers have a few acres as an added en-

;. ;vor. The flowering schedule is from November to June, although a few grow

hprougho't the year. According to Smith and Brooke (4), of the 233 acres of chrys-

nnthemums grown in the 1959-56 season, 222 are in pompons and 11 acres in standard's

Slightly more then half the acreage is under shade, the remainder in the open.

Th:e writer was first introduced to outdoor culture of murs in 1945 at Br'd-

onton. From that time on a list of insects has been assembled with their control

measuress .

No chrysanthemum grower can hope to grow a crop and escape the attack frc"!

insects and mites, hence his rigid control program (1,2,3). Because of his sprP'

program a good share of the enemies described are ever given a second thought-

However, the home owner, who grows a few for his own enjoyment may during the y-i:-

hive had all of the insect pests herein described. NIums are subject to heavy dam-

age by a few serious pests but specific measures, both preventitive and control

give satisfactory results.

Sucking Insects

Aphis

Description of destructive stage. -- Actual size 1/16 inch. There may be many spe-

cies of aphis that attack mums but we have two that are pests, the melon aphis, A-

phis gossPii (Glover) and the chrysanthemum aphis, Macrosiphoniella eanborn'

(Gill.). They are soft bodied plant bugs, pale green to dark red or nearly black

in color. They may be winged or wingless, generally the latter,
I

Nature of injury. Aphis feeding causes the plants to become weak and produce smal2

distorted leaves. They usually infest the new growth, causing the tip to be de-,

formed. The leaves curl inward, and when the flower terminal is infested, the bloom

will be deformed. They will infest open flowers.

Control. -- Spray with parathion mixed at the rate of 1 pound of 15W to 100 gallons

of water. Apply enough of the spray to thoroughly cover the leaves with a fine mist

The size of plants and size of beds determine the amount of spray necessary, Do not

spray if showing color.

If demeton is used, mix at the rate of 1 1/2 pints of 2 pound active material

per gallon to 100 gallons of water and apply at the rate of 100 gallons per acre as

a spray. Applied as a sprinkling, this is 1 gallon of mixed solution to 435 square

feet. If used as a soil application, more water is required and the solution may be

weaker. Use at the rate of 1 pint to 200 gallons of water.

Thrips

Description of the destructive stage. -- Actual size 1/38 to 1/16 inch long. The

young vary in color from light to dark yellow with some greenish cast. The adults

vary from light brown to brownish yellow. No study has been made of the species.

Nature of injury. -- Infest foliage and open flowers. The insects cause general

browning of blooms, especially in warm weather.

Control. -- The grower has the choice of using dieldrin 50 percent WP at 1/2 pound

to 100 gallons throughout the season or of using parathion 1 pound of 15 percent VP

to 100 gallons of water up to the time of coloring. At first sign of coloring use

dieldrin at recommended rate. Records so far show no petal burn when dieldrin is

used properly.

Mealy bugs

Descriptin of the destructive stage. -- Actual size 3/0 inch. They are soft bo-

died sluggish insects. One species is the citrus mealy bug, Pseudooocus citri

(Risso). They are pure white and have a wax coating over then. They are generally

found in clusters on the underneath side of the leaves or in the leaf axils.

-3-

Naturg. n injury. -- Injury is caused to the stems and leaves resulting in a dic-

coloring and deforming of the foliage.

control -- Spray with parathion 1 pound of 15 percent W1 to 100 gallons of wster.,

T;.e waxy covering on the insects may make penetration of insecticide difficult so

it may be necessary to add a wetting agent or iome gdod detergent.

Tarnished Plant Bug

description of destructive stage. -- Actual size 1/4 inch long. The tarnished

plant bug adult, Lygus lineolaris (P. de B) is of a general brown color with a

mottling of white, yellow, reddish brown and black.

h~;ture of injury. -- Small grayish dead areas are left where the insects have fsd.

The sucking beak pierces the tissue of the plant, often causing deforming of the

growth and bending of the tip. The wilting of the tips is a fairly sure indice-

lion of the presence of this pest. Almost invariably the shoots which have been

stung produce no flowers. A flower bud pierced by a tarnished plant bug will not

open.

Control. -- A thorough coverage with a spray of 2 pounds of 50 percent 'P DDT to

100 gallons of water is an effective control.

Southern Green Stink Bug (Pumpkin Bug)

Description of destructive stage. -- Actual size 1/2 inch long and almost as broad,

The full grown southern green stink bug, Nezara viridula (L.), is of a light grsa

color. The immature stages are bluish, with some red markings.

i',ture of injury. -- Both adult and immature stages damage the foliage and stems

by sucking the juice. Injured plants may turn brorw and wither.

Control. -- Spray with parathion 15 percent V'r at 1 pound to 100 gallons of water

or chlordane 40 percent WP 2 1/2 pounds to 100 gallons of water.

Spittle Bugs

Desaciption of destructive stage. -- Actual size 1/8 inch long. The undetermined

species belong to the Cercopidae. Bits of saliva-like material adhering to the

-4-

stems of mum plants denote the presence of the greenish or yellowish insects. Ths

is the immature form of the spittle bug.

1ture of damage. -- The tips of the leaves usually curl where these salivn masses

are present.

Control. -- DDT applied at the rate of 1.5 pounds active ingredient per acre

irhich is 3 pounds of 50 percent wettable, has given good economic control. Lir.'nre

nt the rate of 1 pint of 25 percent emulsion per acre gives even better control.

The wettable powder is applied at the rate of 0.2 pound gamma isomer per acre.

Toxaphene at the rate of 1 quart of 60 percent emulsifiable concentrate (1.5 pound

active) per acre has proven equally as effective. The 40 percent wettable poiwder

is applied at the rate of 1.5 pounds per acre.

White flies

Description of destructive stage. -- Actual size 1/6 inch. There are several s'e-

cies of white flies (Aleyrodidae) that infest citrus and some of these may infee

pompons. The larvae of these flies are small, light green scale-like organisms

that feed on leaves. They are sucking insects. The adults are winged and white

in color.

nature of damage. -- Plants grown near trees that harbor white flies may becolra

infested with small white flies that suck the juice of the plant causing it to turn

yellow and die. The larvae exude a honeydew which gives the foliage a glazed ap-

pearance.

Control. -- Spray with a parathion 15 percent WP at the rate of 1 pound to 100 gal-

lons of water.

Leafhoppers

Description of destructive stage. -- Actual size 1/20 to 1/4 inch rarely larger

than 1/4. These small yellowish-green insects are particularly troublesome because

they are attracted to lights which are an essential part of chrysanthemum growing.

nature of damnae. -- The insects produce damage to the leaf by sucking out the

juice from the underneath of the leaf, leaving a tiny yellow spot on the upper sur-

*5-

face. Leafhoppers besides producing damage to the leaves may carry virus disease

from plant to plant. Spray thoroughly with DDT at recommended strengths several

.rr3s during the season. Keep premises free from weeds and grass or else keep

them sprayed with DDT regularly.

Leafhoppers are worse from the latter part of May until the middle of J~ly.

:'-y come in from surrounding vegetation and damage is always greater on the out-

~-.de rows and gradually works in toward the center of the planting,

Mites

The two-spotted mit, etranychus telarius CL.) and the red spider, ebi-

rlus cinnabarinus Boisduval (carmine form of the 2-spotted mite) are two common

s:3cies. There may be more. These mites are found on many weeds, so infestaticn

is simple.

s:;scription of destructive stage. -- Actual size 1/64 inch. Generally more yellow-

.'eh or orange than red. Very small. Usually found on under surface of leaf.

Nature of damage. -- First sign of injury is pale green mottling of upper leaf su--

fce. Will eventually cover lower surface with fine spider webs, later will spin

web over stems, buds and even support stakes.

1'ntrol. -- Control measures vary in effectiveness as regards location, season of

year and abundance of the pest. Demeton applied at rate of 1 to 1 1/2 pints per

10 gallons of water (4-6 ozs, active ingredient) has proven successful upon cer-

tain occasions. Kelthnne '.P. applied at 2 pounds to 100 gallons of water has

-roven quite effective. Aramite used at 1 1/4 to 1 1/2 pounds to 100 gallons of

iater has proven effective at times.

Greenhouse Orthezia

Dscription of destructive stage. -- Actual size hard to describe as the long white

S-fluted egg sac of the female may reach a length of 3/4 inch in length. The actual

insect, the greenhouse orthezia, Orthezia insignis Douglas is about 1/8 inch in

length.

Mature of damage. -- The insects settle on the leaves and stems of the plants suck-

-6-

ing the juice and causing the plant to become yellow, sickly and finally die if

not treated.

Control. -- Spray with parathion 1 pound of 15 percent !".P. to 100 gallons of water

Add a wetting agent or detergent to facilitate penetration of the waxy covering.

Chewing Insects

Leaf tier

Description of destructive stage. -- Actual size, 1/2 inch. This undetermined spe-

cies ties foliage together with web; it ruins the foliage appearance. Its name .s

derived from its habit of spinning light web enclosing two or more leaves or ;t'vIg

together the parts of a single leaf. The caterpillar is very active, and when -is-

twi&e~d will wiggle off the leaf, often bpcktards, lowering itself on a silk-lika

strand.

,rture of damage. -- Then first hatched, the larvae eat out shallow holes on th;

under side of the leaves. 4s they grow, they enlarge these holes but usually do

not cut through to the upper surface. The result is that the leaf is skeletoni-,-.

Control. -- Direct the spray against the underside of the foliage. Use DDT or prli-

thion or a combination of the two especially if the insect has rolled or tied tbh'

'leves together.

Leaf miners

Description of destructive stage. -- Actual size 3/16 1/4 inch long. The adult

i.s a tiny shining black fly marked with yellow in various ways. Larvae of the ser-

rentine leaf miner, Liriomyza pusilla eeig.) are yellow or orange colored and do

the tunneling.

Nature of damage. -- Most common injury is the serpentine mines made by the small

bright yellow to orange larvae. The tunnel leaves the upper and lower leaf surface

intact.

Control. -- Spray with parathion 15 percent "1.P. at the rate of 1 pound to 100 gal-

longs of uiter.

-7-

Corn Earworm

Description of destructive stage. -- Actual size of larvae 1 1/2 to 2 inches. The

full grown larvae of the corn earworm, Ieliothis zee (Boddie) are of variable crlo:'-

rF-ining from pink, green or yellow to almost black. The side is marked with a long-

:i.'dinal stripe consisting of a pale stripe edged above with black. There is a dark

,, .ripe along the middle of the back divided longitudinally by a narrow white line

Yature of damage. -- They chew the flower buds.

0.-itrol. -- Spray with 2 pounds 50 percent DDT to 100 gallons of water.

Cutworms and A~myworms

description of destructive stage. -- Actual size 1 1/2 to 2 inches. These are cf

v7Bious colors and markings. There are several species.

Nature of damage. -- Cutworms cut off the young plant and armyworms eat foliage

and chew buds.

Control. -- Chlordane applied to soil at the rate of 2 1/2 pounds of 40 percent

wettable to 100 gallons of water or 30 pounds of 5 percent dust will control the

larvae. In commercial plantings, soil sterilization keeps these pests under control

Sowbugs

Dscription of destructive stage. -- Actual size 3/8 to 5/8 inch. They are dark

grey with a lighter gray underneath. They are crustaceans, related to crayfish and

crabs, and are not insects. They are found in moist areas usually near some decayed

matter. They seldom appear during the daytime.

Nature of damage. -- They feed on the roots and tender portions of the plant.

Control. -- Chlordane applied to the soil as a spray at the rate of 2.5 pounds of

40 percent W1.P. to 100 gallons of water or 30 pounds of 5 percent dust or granules

will control these pests.

Salt-marsh caterpillar, Woolly bear

Description of destructive stage. -- Actual size of full grown larvae of the woolly

bear, Eatigmene acraea (Drury) is 2 inches in length. The larvae are hairy or wooly,

brown to dark brown in color.

-8-

Nature of damage. -- The pest may move in rapidly from adjoining fields and over-

night ruin blocks of chrysanthemums. Because the pest is migratory and capable cf

fast locomotion, it can damage considerable areas in a short time. Migrating lrr-

vna are heavy feeders and are difficult to control.

Cc,'trol. -- This pest is the one exception where a dust is advisable, despite the

e of growtof row f the forms because .of the vorecaousaest of :the insect. A th.c-

cligh dusting of 5 percent DDT will control the pest. It is necessary to repeat the

dusting within a day or so to kill caterpillars missed by the first dusting.

Grasshoppers

Description of destructive stage. -- Various sizes up to the large lubberlyi* There

aro several species.

Nat-rre of damage. -- Grasshoppers can move in suddenly and cause severe damage to

flowering plants by eating foliage, flowers and tender growth;

Control. -- Aldrin applied at the rate of 1/2 pint of the emulsifiable concentrate

per acre is effective. Toxaphene sprayed at rate of 1.5 to 2 pounds of the 40 p:r-

cent wettable per acre is effective.

Geometrid measuring worms

Description of destructive stage. -- The larvae of this group are called measuring

worms, spanworms or loopers because of their method of locomotion, which is one of

looping or measuring. Identification is made easier because these larvne do not havi

any legs in the middle of the body, only at the head end and rear end. They can ft-

toch themselves by their rear legs and assume the likeness to a dry twig. One spe-

cies known to attack mums is Synchlora rubrifrontarin Pack.

Nature of damage. -- Injury results from their eating leaves or florets.

Control. -- Apply DDT 50 percent W.P. at rate of 2 pounds to 100 gallons of water,

Cabbage looper

Description of destructive stage. -- Actual size of full grown larva is 1 1/4 in-

ches. The pale green larvae have a narrow white stripe along each side of the body;

and two others along the middle line of the back. They travel with a looping measure

-9-

ing motion of the body.

Nature of damage. -- The young larvae eat small holes in the leaf but do not com-

pletely penetrate the leaf. As the larvae increase in size they eat the more tendeg-

l~ieves and frequently ruin the bud.

Control. -- DDT applied at the rate of 3 pounds of 50 percent W.P. to 100 gallons

o.F water or toxaphene at 1 1/2 pounds of 40 percent W.P. will control the insect.

TDo not dust because of danger of spotting the petals.

Termites "white ants"

Description of destructive stage. -- Actual size variable bet 3/16-3/4 inches. Tbh

destructive stage are wingless, usually pale-colored, soft bodied and possess c0.oT-

in2 mouthparts. They are called white ants but are not an ant or related to ants.

Nature of damage. -- Termites have caused the loss of iany chrysanthemum plants a-

round the home. They injure or kill a plant by tunnelling the stem. Around the

home, a wilted plant is a likely suspect for termite injury. Cutting across the

Etem will frequently reveal the presence of the termites. Nothing can be done fcr.

the plant once the termite attack has progressed this far.

Control. -- Termites can be eliminated from the soil by the use of chlordane, di.-

d~in or certain gaseous soil fumigants, such as MC-2, DD or EDB. The chlordane o-

dialdrin is applied to the soil at the rate of 1 ounce of active material to 1000

square feet.

References

1. Ball, Geo. J., Inc., Ball Mum Guide. 1955.

2. Glockner, Fred C, & Co., Gloeckner's Chrysanthemum Manual. 1952.

3. Kiplinger, D.C., Greenhouse and Garden Chrysanthemum. 1954,

4. Smith, Cecil N. and Brooke, Donald L. The Florida Chrysanthemum Industry, ASr.
Ec. Mimeo Report 56-10. Vla. Agr. Expt. Sta. 1956.