Front Cover
 Table of Contents
 Introduction and control proce...
 Rose diseases
 Insects and mites
 Control of insects and mites
 Control of nematodes
 Control of diseases
 Back Cover

Title: Rose diseases and insects in Florida
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00084349/00001
 Material Information
Title: Rose diseases and insects in Florida
Series Title: Rose diseases and insects in Florida
Physical Description: Book
Publisher: Florida Cooperative Extension Service, University of Florida
 Record Information
Bibliographic ID: UF00084349
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 214324137

Table of Contents
    Front Cover
        Page 1
    Table of Contents
        Page 2
    Introduction and control procedures
        Page 3
        Page 4
        Page 5
    Rose diseases
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
    Insects and mites
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
    Control of insects and mites
        Page 20
        Page 21
    Control of nematodes
        Page 22
        Page 23
    Control of diseases
        Page 24
        Page 25
        Page 26
    Back Cover
        Page 27
        Page 28
Full Text


and Insects
in Florida

H. N. Miller, R. S. Mullin, D. E.
L. C. Kuitert, and R. A. Dunn e
Florida Cooperative Extension Service
University of Florida, Gainesville
Institute of Food and Agricultural Sciences

{' / -fC ,/^k
(,9 'b ( "

Introduction ........ ........................- ----- 3
Control Procedures ... ................. ............ --- 3
Spray Equipment -........................... 3
Application Methods ......................... .---- 3
Precautions ... ........................... 4
Rose Diseases 6.. -..........- ...... ---- -------- ---- 6
Black Spot ............ ......- -------- -------------- 6
Powdery Mildew .......................- 6
Cercospora Leaf Spot ........ ........--------------- 7
Rose Mosaic ..... ........-- 8
Rose Rust .......... ...... ....-- --.--- --- 8
Downy Mildew ....................... --- ------ 8
Dieback ....... 8
Cankers ... ................ . ... 9
Crown Canker ................. ........ 10
Crown Gall .........---- 10
Mushroom Root Rot .................... 10
Nematodes .... ........... .. -- 11
Insects and Mites -............. --- 12
Mites .. .. --.............- ----- --- -- - 12
Aphids ......... ........... .- -- -- 13
Flower Thrips ........................... -- 14
Stink Bugs & Plant Bugs .. .. 15
Caterpillars --- .............. .-- ---------- 17
Leaf Cutting Bees .... 17
Scale Insects ... ........ ..... ..... ------- 18
Beetles and Grubs ..................... -- 19
Appendix ----. .....-- -.....-. .....--------- 20
Control of Insects and Mites ---......--....... ----------.- 20
Control of Nematodes ............. ------------------. 22
Control of Diseases ..---.-...........-----------------24

H. N. Miller, R. S. Mullin, D. E. Short,
L. C. Kuitert, and R. A. Dunn'

There are many potential dis-
eases of the rose. Fortunately,
only a limited number of these
occur in Florida. Black spot and
powdery mildew may be limiting
factors in the production of roses
in this state and lack of adequate
control practices may result in
failure. Other diseases common in
some localities, such as downy mil-
dew, leaf rust and anthracnose, are
seldom observed here. Rose dis-
eases may persist over longer peri-
ods of time and be more difficult
to control in Florida than in other
parts of the country.
Mites are a major problem on
roses. They are usually present
every month but may be especially
bothersome in the spring and fall
months. Heavy summer rains tend
to reduce the mite population.

Japanese beetles, especially dam-
aging in some areas, do not occur
in Florida. Root injury by para-
sitic nematodes seldom kills roses,
but these organisms can reduce
vigor and flower production con-
Rose pests can be effectively
controlled if general recommenda-
tions are followed.

* Buy plants that are free of dis-
eases and insects.
* Keep the rose planting free of
weeds, fallen leaves and diseased
or insect-infested plants or
* Use a regular spray program and
specific control measures as sug-
gested in the tables at the end
of this publication.


Spray Equipment. A 2 to 5
gallon tank, hand pumped, com-
pressed air sprayer or compressed
air tanks with suitable valves,
spray boom and fine mist nozzle are
very satisfactory sprayers for
home gardens. These sprayers
should have a long reach hose and
boom with an angled or swivel
nozzle, so that the spray can be
directed upward to cover the lower
surface of the leaves. They should
operate at pressures of 40 to 60
pounds, for satisfactory results.
Small sprayers that do not have
some type of agitation must be
shaken frequently while spraying
to keep wettable powders sus-

The most satisfactory garden
sprayers are the power-driven pis-
top-pump types which will deliver
1010 to 200 pounds pressure, and are
equipped with 50 to 75 feet of
pressure hose. Power sprayers
provide essential agitation for the
solutions or suspensions in the
Application Methods. Apply
sprays in a very fine mist. The
plants should be thoroughly cov-
ered, including the canes and both
top and bottom surfaces of the
leaves. Start spraying at the bot-
tom of the bush with the spray
nozzle directed upward, and work
from side to side toward the top.

'Plant Pathologists, Associate Entomologist, Entomologist (retired), and As-
sistant Nematologist, respectively, Institute of Food and Agricultural Sciences, Uni-
versity of Florida.

At the top, turn the nozzle down-
ward to finish coating the upper
surfaces of the top leaves.
Follow the manufacturer's di-
rections for mixing spray materials
carefully. The indicated amounts
of wettable powders should be
accurately measured or weighed
and placed in a small container.
Mix thoroughly just enough water
with the chemicals to give a thin
smooth paste or slurry. While
stirring, add this mixture to the
remainder of the water needed.
Black spot should be prevented
because the disease is very difficult
to control once it has become well
established; therefore, spraying
should be started as soon as the
first leaves appear after planting
and must be continued on a regular
basis. Other diseases occur inter-
mittently or sporadically. They are
described in the hope that the gar-
dener will recognize the trouble
and initiate the control steps as
Control materials for insects and
mites can be combined with the
spray for black spot, so that the
problem is mainly one of prompt
recognition of the pest, and addi-
tion of the proper insecticide to the
spray. The spray application for
insect control should be repeated
after 7 to 10 days in order to kill
the new hatch from eggs un-
harmed from previous spraying.
Chemical pesticides are a neces-
sary part of successful rose cul-
ture. In general, many pesticides
cause some direct injury to the
plant. Some chemicals may, under
certain conditions, cause severe
leaf injury (Fig. 1). When properly
applied, injury to the plant is
slight, and the benefit to the plant
resulting from the control of the

pest organism is great.
Spray materials that contain oil
should be avoided because they
cause severe injury to rose leaves.
New growth turns black, resem-
bling cold damage. Compounds con-
taining mercury will cause severe
injury; those containing copper
will injure foliage when applied
during cool weather. Sulfur, ap-
plied when temperatures are above
850 F, may result in severe leaf
The pesticides and methods of
application that are listed in the
tables were selected because of
their relative safety to the user
and to the plant, as well as their
effectiveness in controlling pests.
Precautions. Most insecticides
are poisonous to birds, fish, pets
and man. Some general precau-
tions to be observed when handling
these materials are:
1. Read the label and follow
2. Use only recommended mate-
rials at recommended rates.
3. Avoid ingesting or inhaling
these pesticides.
4. Avoid coming in contact with
spray materials. Stand to
the windward side while ap-
plying the materials to avoid
5. Unused lots of pesticides
should be stored in their
original containers out of the
reach of children and pets;
preferably in a locked cabi-
6. Dispose of empty containers
promptly by burying or burn-

Fig. 1. -- Chemical spray injury to foliage: (A) superficial blackening of areas
on the upper surface of leaves; (B) tip burning resulting from concentration
of chemical in water droplets; (C) leaf spotting and distortion.

Fig. 2. Black spot lesions showing all stages of development. Yellowing of leaf on
left caused by the numerous infections.


Black Spot (Diplocarpon rosae)
(Fig. 2).-Caused by a fungus,
black spot is the most continually
damaging disease of roses in Flor-
ida. Circular black spots, with
jagged margins appear on the
leaves. The spots are frequently
surrounded by a yellow halo. In-
fected leaves turn yellow and fall
prematurely when the attack is
severe and allowed to continue, re-
peated defoliation occurs, greatly
weakening the plant. Spores of the
fungus are spread mainly by
splashing rain or water. The
spores germinate and infection
takes place only when water re-
mains on the leaves for periods of
6 hours or longer. Typical leaf

spots develop within 5 to 10 days.
Powdery Mildew (Sphaerothecoa
pannosa) (Fig. 3).-This fungal
disease occurs in Florida during
the spring and fall. It is not usually
a problem during the mid-summer
months when black spot is at its
worst. The disease is inhibited by
frequent rains and temperatures
above 800F. Powdery mildew is
characterized by white powdery
growth, masses of spores on young
leaves, shoots and buds. Foliage
may be distorted, and shoots stunt-
ed or swollen.
Spores of powdery mildew are
not spread by splashing water, but
are wind-borne. They germinate
under conditions of relatively high

Fig. 3. -- Powdery mildew of rose on leaf and flower buds. Note curling and distortion
of leaflets.

humidity, but, in contrast to the
spores of the black spot fungus,
germination is hindered by the
presence of free water.
Cercospora Leaf Spot (Cercos-
pora puderi) (Fig. 4).-Charac-
teristically, Cercospora leaf spots
have distinct gray centers with
purplish or reddish brown borders.
This characteristic can be used to
distinguish the disease from black
spot. Infected leaves may hang on
the plant for some time, but usual-
ly turn yellow and drop before they
would normally.
The appearance of Cercospora
leaf spot is often associated with
faulty or poor growing conditions.
Where drainage is poor, or where
proper feeding and general cul-
tural care is neglected, it is likely
to appear during any season of the

Fig. 4. -- Cercospora leaf s-ot of rose show-
ing dark circular lesions with gray centers.

Fig. 5. Rose mosaic.

Rose Mosaic (Fig. 5). -This
disease is caused by a virus. In
Florida the expression of symp-
toms varies a great deal with the
season. The symptom of mosaic
are bright yellow patterns on green
leaves that appear as mottles,
wavy lines, or oak-leaf patterns.
Rose mosaic spreads only
through propagation. No known
insect vector is capable of trans-
mitting the disease from infected
to heaithly plants. For this reason
an infected plant in a garden is not
a menace to surrounding plants.
Mosaic infected plants should
not be bought or used for propaga-
tion. Severely infected plants
which are stunted by the disease
should be dug and destroyed. The
only control for viruses is preven-
Rose Rust. (Phragmidium disc-
iflorum) (Fig. 6) Rust is easily
recognized because of the bright
yellow or orange pustules which
occur on the undersurface of the
leaves. The spots appear light yel-
low when viewed from the upper
surface. Long, narrow, orange

Fig. 6 -- Rust on rose leaves. Bright
yellow to orange pustules show on the
under surface of the lesions.
spots may be found on young
While this fungal disease has
not been a continually serious
problem on roses in Florida, it is
becoming more widespread and
may be a problem in some areas.

Downy Mildew. (Peronospora
sparsa) (Fig. 7) Yellowish to
brown blotches appear on upper
surface of the leaves. The blotches
may frequently occur along the
leaf margins. Under moist, cool
conditions leaves may turn yellow
and drop. A greyish, downy fun-
gus growth may occur on the lower
surface of the leaves. Under drier
conditions leaf spots appear as
brown, burned areas. Infected
leaves frequently show a crinkled
appearance. Reddish streaks may
occur on flower stems and canes.
Dieback. (Diplodia spp, Botry-
osphaeria spp and Botrytis cin-
erea) (Fig. 8 & 9) This condi-
tion occurs as a dying back of the
canes or shoots from the tips, fol-
lowing a pruning wound or an in-
jury. Several fungi may cause, or
are associated with dieback of

roses in Florida. The parasites
enter the stems through injuries,
pruning wounds or insect punc-
tures, or attack plants that have
been weakened by some other
cause. Dieback is often more prev-
alent on plants that have been de-
foliated by black spot. Plants that
have been growing in poorly drain-
ed areas or suffering from poor
nutrition may be more susceptible
to this condition. Infection of plant
roots with crown gall or nema-
todes may predispose the plants to
Dieback caused by Botrytis is
most common in greenhouse cul-
ture but may be a problem in the
field or gardens during cool, humid

Cankers (Crytosporella umbri-
na, Cylindrocladium floridanum,
Leptosphaeria coniothyrium, and
Botrytis cinerea) (Fig. 10 & 11). -
Cankers on roses occur as localized
diseased areas on canes. If a cank-
er is allowed to remain and the

disease spreads down the cane, the
entire cane and lower branches
may be killed. The cankers most
frequently found in Florida are
brown canker, stem canker and
Cylindrocladium crown or stem
Brown canker is first noted as
small purplish spots with bright
grey or brown centers and pur-
plish margins on the canes. Many
small spots are usually grouped to-
gether forming a sunken, cracked
area which may girdle the cane re-
sulting in death of the cane.
Stem canker is present in al-
most every rose garden, but the
fungus which causes the disease is
a weak, wound parasite. The cank-
ers may or may not have a definite
outline but are distinguished by
masses .of small fungus fruiting
structures under the. bark. These
structures (pycnidia) are filled
with small dark, globose spores. If
the canes are girdld, dieback re-
sults. Frequent rose spraying for
black spot control and proper
maintenance usually keeps this
disease under check.

Fig. 7. -- Downy mildew on rose leaves. Fig. 8 -- Diplodia dieback of rose
canes and twigs. Note margins of dead areas and withered shoots. Fig. 9. -- Botrytis
dieback. Note grey mass of fungus and spores on dead stem.



Crown canker (Cylindrocladi-
um) is most severe on canes dur-
ing propagation and on crowns of
small plants. The bark darkens
into black water-soaked punky re-
gions on the stems or crowns.
Spore masses may be formed on
the blackened areas. The fungus
lives in the soil and enters through
wounds. The use of disease free
propagation material, and steri-
lized soil is essential in keeping
this disease to a minimum.

Crown Gall (Agrobacterium tu-
mefaciens) (Fig. 12). This is a
bacterial disease somewhat com-
mon on roses. Weakened or dying
bushes are sometimes found to
have a large gall near the crown.
Small galls may appear on roots.
The bacteria live in the soil where
they may survive for at least 2
years in the absence of plants.
They enter the rose through in-
juries made in grafting or culti-
vating or by rodents or insects.
Only crown gall free plants should
be planted. Avoid wounding plants.

Mushroom Root Rot (Clitocybe
tabescens) (Fig. 13 & 14). This
disease is becoming increasingly
devastating to roses in Florida.
The fungus is soil-borne and often
lives on oak roots or decaying roots
of many plant types. Infection is
by root contact. When rose roots
come in contact with infected roots
or root pieces of other plants, in-
fection may occur. Top symptoms
do not usually show until the fun-
gus has killed a large part of the
root system or crown of the plant.
At this point a part or all the plant
may wilt. The leaves become dry
and remain on the plant. Slow de-
cline and death of the plant fol-
lows. A layer of white, matte-like
fungal growth can be found be-
tween the bark and wood on the
crown and upper, larger roots.
This characteristic is a positive
diagnosis of mushroom root rot.
Clusters of mushroom fruiting
structures may develop around a
dead plant in the fall of the year.
The caps are light tan to honey-
colored, 2 to 4 inches in diameter.

Fig. 10. -- Brown canker on rose cane. Fig. 11. -- Cylindrocladium canker
on rose cane pieces from propagation. Fig. 12. -- Crown gall of rose (left) gall on
cane, and (right) severely galled roots.

* Ama

They are more often seen around
dead tree stumps. Clitocybe root
rot is most prevalent on land
cleared of oak and other hardwood

Fig. 13. -- Mushroom root rot of rose.
Note the white fungus growth where
the bark has been peeled away.
Nematodes (Fig. 15). Nema-
todes are microscopic filiform
worms which live in the soil and
are capable of causing various
plant diseases by feeding on plant
roots. The danger of nematodes to
roses cannot be over-emphasized
because of the damage they may

do. Several nematode types may
attack roots. The most important
of these nematodes are root-knot
and lesion.
Root-knot nematodes cause
small, nodule-like galls on the
fibrous roots of roses (Fig. 16).
Yellowing of the foliage, stunting
and gradual decline of the plant
results. Any plants from a nursery
which show galling should be re-
Lesion nematodes do not produce
galls on the roots, but kill the
feeder roots from the tips. Many
new short fibrous roots may be
formed, resulting in a bunching
or witches' broom effect. Dieback,
stunting and death of the plants
may occur.
Other nematodes feeding on or
in the roots may cause stubbiness
of roots, various types of root
lesions, and death of roots.
Unhealthy plants in a planting
should be checked for nematodes
and if found infected, treated ac-
cording to suggested procedures.

Fig. 14. -- Mushroom (sporophores) of Clitocybe. Fig. 15. -- Plant para-
sitic nematode larva. Fig. 16. -- Root-knot nematode galls and distortion on rose


Mites (Fig. 17). Spider Mites,
commonly called "red mites" are
frequently serious pests. The two-
spotted spider mite, Tetranychus
urticae (Koch) is our most impor-
tant species. Mites are closely re-
lated to the spiders, ticks and scor-
pions. They are extremely small
1/50-inch or less in length and
are soft-bodied and oval shaped.
They commonly infest the under-
sides of the rose leaves and spin
extensive webbing. Silvery-white
spots result when the needle-like
mouth parts puncture the leaves.
Fig. 17 Spider Mite Injury and Webbing.

Later these spots turn yellow,
bronze and reddish. Mites suck the
plant sap and chlorophyll causing
the tissues to die and the affected
leaves drop.

Rose plants only moderately in-
fested by mites lose much of their
foliage; consequently, assimilation
is greatly reduced resulting in un-
thrifty growing conditions.

Spider mites pass through sev-
eral stages in development from
egg to adult. The yellowish-white

Fig. 18.--Aphids on rose leaf. (photo by L. S. Maxwell)

eggs are laid along the main veins
on the underside of the leaves.
Females may lay 7 to 8 eggs per
day for 15 days but may live and
oviposit for a month under our
summer conditions. The approxi-
mate days spent in each stage at
the usual summer temperatures
are: egg (3 to 4); 6-legged larva
(1) ; first quiescent (1) ; 8-legged
protonymph (1/%,); second quies-
cent (1+); third deutonymph
(11/) ; third quiescent (1); and
Many of the miticides kill spider
mites only when they are in the
active stages. Those miticides
which kill only by contact do not

kill the quiescent stages. Thus
applications must be repeated, and
this frequently results in plant in-
jury. Those miticides having resi-
dues toxic for 2 or more days will
kill mites hatching from eggs and
the active forms emerging from
quiescents. Several chemicals have
proven effective in destroying mite

Aphids (Fig. 18) Aphids, or
plant lice, are soft-bodied, sucking
insects. They may be greenish,
yellowish or black in color. They
are usually less than l-inch in
length and most aphids are wing-
less. Aphids live in colonies on the

succulent new growth and their
continuous draining of plant juices
causes the buds to become stunted
and hardened and the leaves to
become thickened, curled and dis-
The rate of development and re-
production is extremely rapid and
many generations may be produced
in a year. Unlike most insects,
aphids seldom lay eggs but give
birth to living young. Another
peculiarity of aphid reproduction
is that in most generations all indi-
viduals are females which repro-
duce parthenogenetically-that is,
without mating. A single female
often produces 100 progeny during
her lifetime and the young aphids
mature 6 to 7 days after birth.

When colonies become overcrowd-
ed or the plants harden, winged
forms appear and these fly to other
host plants and establish new
Aphids excrete a sweet liquid
called honey dew which is attrac-
tive to ants and makes an excellent
medium for the development of a
black fungus called sooty mold.
The sticky honey dew secretions
and the accumulation of cast skins
from the molting nymphs, along
with the sooty mold, result in very
unsightly, objectionable foliage.
Several effective aphicides are
available and prompt application
will avert aphid infestations.
Flower Thrips (Fig. 19). For
several weeks during the spring

Fig. 19- Flower Thrips Injury. Note darkened areas near base of petals and in center
nf flnwar

(late March-April) flower thrips
become extremely numerous and
migrate from the flowers of weeds
and grasses to roses. Adult flower
thrips do not feed on foliage but
enter the flower buds. Thrips
puncture the plant tissue, suck the
exuding sap and deposit excrement,
causing browning and deformed
petals as the flower develops. In-
fested buds fail to open. Thrips
are very active and when alarmed
will turn up the tip of the abdomen
as if to sting.
Adult thrips are about 1/-inch
in length. They are slender in-
sects, yellowish to brownish in
color and have bristle-like wings.
Flowers suspected of being in-
fested should be shaken vigorously
over a sheet of white paper to
detect them. Although adult thrips
lay eggs in the buds, the flowers
complete development and usually
are cut before the young thrips
mature to the adult stage.

Fig. 20 Stinkbug Feeding Causes De
formed Buds and Flowers.

Several insecticides are very
effective in controlling thrips;
however, due to the constant rein-
festation by migrating forms dur-
ing the peak of the thrips season,
growers frequently will assume
their control measures are at
fault. The objectionable damage
is most conspicuous on the white
and yellow varieties. Old and
heavily infested flowers should be
removed and destroyed.
Stink bugs and Plant bugs (Figs.
20-21). These insects, although
seldom numerous, are serious pests.
They have sucking mouthparts
and the front pair of wings is
thickened. The wings are folded
flat over the back when at rest.
Both the immature and adult
stages suck on the buds and tender
shoots. Feeding on the shoot often
causes it to wilt and die, while
feeding on the flowers results in
distorted buds and discoloration
of the petals.
Fig. 21 Leaf Footed Plant Bug. Its
feeding causes discoloration where the
petals have been punctured and malfor-
mation of the flower.

Fig. 22 Caterpillar in-
jury to rose buds; (A)
young corn earworm larvae
and feeding holes; (B) lar-
val feeding holes may ex-
tend to interior; (C) por-
tion bud completely de-

Caterpillars (Fig. 22) Cater-
pillars are the immature stage of
moths and butterflies. They have
chewing mouth parts and are very
destructive during the summer
months. Without a doubt the most
damaging caterpillar involving
roses in Florida is the corn ear-
worm. It is known to attack a
number of other plants and is also
known as the cotton bollworm and
tomato fruitworm. The Eastern
tent caterpillar causes considerable
damage to the foliage and flowers
in the spring. The favorite host of
the caterpillar is wild cherry; how-
ever, when the larvae are about
full grown they leave the host to
seek out pupation sites. Roses
close to the cherry tree hosts may
be damaged extensively before pu-
pation occurs. The fall armyworm
and measuring worm also feed on
the flowers, while several other
species feed on the foliage.
The adult corn earworm moth
deposits its white, shiny eggs on
the rose bud. The eggs hatch in
2 or 3 days. The larvae are very
small (1/16-inch) when they
emerge from the egg. The destruc-
tive caterpillar or larva bores into
the bud. After feeding for 2 or 3
days the caterpillar molts (sheds
its skin) and in the process in-
creases in size. Most caterpillars
will molt 5 times. The full grown
larvae are 11/ inches in length and
enter the soil to pupate (trans-
form to the adult moth). Although
only a few larvae are able to de-
velop to maturity in roses they
should be controlled to prevent
extensive losses.
Leaf cutting bees (Figs. 23-24).
- These solitary, hairy, wasps are
mostly medium to large size and

resemble honeybees. They gener-
ally are black or metallic dark blue,
purple or green in color with white,
yellow or reddish pubescence. The
nests are made in burrows in rot-
ten wood or in hollowed out stems
of pithy plants, in holes in wood
and sometimes in neglected garden
hoses. The cells are lined with
oval and circular shaped pieces of
foliage cut from the leaves of
roses and other plants. The several
cells are arranged end to end.
Each cell is provisioned with
nectar-pollen paste, and a single
egg is deposited on the food in each
cell. When the eggs hatch the
young larvae have a ready source
of food. The tunneled stems usually
die back for several or more inches.
Treat the cut ends of pruned canes
with tree wound paint to prevent
infestation or push a thumb tack
into the cut end of the large canes
to close the wound.
Fig.23. Leaf-Cutter Bee Injury to Fo-
liage. Circular sections cut from margin
of leaflet by the adult bee are used to
line its egg nest.

Fig. 24 Wasp Injury to Rose
Cane: (A) top view of a pruning
cut with wasp at entrance to tun-
nel; (B) Cut away sections show-
ing how wasp removes the pith
from center of stem. Egg nests
may be as much as two feet below
entry cut.

Scale Insects (Fig. 25). Sev-
eral species of scale insects -
including rose, dictyospermum,
brown soft and cottony cushion R
scales are frequently serious
pests. Old stems sometime,' be-
come encrusted with the rose and
dictyospermum scales, while brown
soft and cottony cushion scales
prefer newer growth.
The adult female rose scale is
circular or oval when crowded. Its
diameter varies from 1/10- to 1/8-
inch. It is usually white or dirty
white and has a dull yellowish
exuvium or nipple near the margin.
The adult female dictyospermum'
scale is similar but somewhat'
smaller, grayish in color and has
a ringed nipple near the center.
The adult female brown soft scale
is oval, 1/10 to 1/16-inch in length. (

Fig. 25 Brown Soft Scale with Immatures (20x)

It is a yellowish or greenish brown
color. The adult female cottony
cushion scale is brick red or
orange, and the posterior portion
of the abdomen is covered with a
loose, flutted, white, cotton-like
material. It is about l/,-inch in
Beetles and Grubs Both the
immature and adult stages of

beetles feed on roses and both have
chewing mouthparts. The adult
beetles have a hard shell and vary
from 1/10- to more than an inch
in length. Usually adults feed on
the foliage and flowers while the
larvae or grubs feed on the roots.
Many beetles are beneficial and all
gardeners should learn to recognize
these beneficial forms.


of water***
Concentra- (level of
Pest Description Insecticides* tion** measures) Remarks

Scale insects:
Brown soft,
Cottony cushion

Feed in flowers; cause
spotting and discolora-
tion of petals.

Adults feed by sucking
on succulent new growth.
Cause distortion of flower
buds and young leaves.

Appressed to older stems.
Feed with sucking mouth-
parts. Found on younger
stems and leaves.


Dimethoate 2 E.C.

Diazinon 25% E.C.



2 tsp.

2 tsp.

15.6% E.C. 11/2 tbs.

25% E.C.

Dimethoate 2 E.C.

Malathion 57% E.C.





112 tsp.

2 tsp.

2 tsp.

Most prevalent in late
spring and early summer
when they migrate from
wild hosts to cultivated
plants. May have to
treat during this period.
Frequently have second
"peak" in the fall.

Most troublesome in early
spring, although they
may be found any time.

15.6% E.C. 1 tbs.

2% Granules

25% E.C. 2 tsp.

25% E.C.

Dimethoate 2 E.C.



25% E.C.

11/ tsp.

2 tsp.

2 tsp.

15.6%, E.C. 1 tbs.

Seldom very serious when
plants are treated for
controlling other insects
and mites. May be pre-
sent at almost any time
of year.

Diazinon 25% E.C. 2 tsp.

Flower thrips



of water***
Concentra- (level of
Pest Description Insecticides* tion** measures) Remarks

Lygus bugs

Corn earworm,

Tussock moth,

Eastern tent

Flower beetles,

Leaf beetles

Two spotted mite,
Red spiders,

Suck buds; cause
spotting of petals

Eat holes in
flower buds.

Feed on foliage.

Adults feed on
foliage, eat holes
in flower buds.

Cause bronze discolora-
tion and light stipled
areas on leaf; tiny
animals barely visible
to naked eye: usually
on lower side of leaf;
silk strands present
when numerous.

Dimethoate 2; E.C.












1 tsp.

50% W.P. 2 tbs.

25% E.C. 2 tsp.
50% W.P. 2 tbs.

15.6% E.C. 11/2 tbs.

Follow label

50% W.P. 2 tbs.

25% E.C. 2 tsp.

18.5% E.C. 1 tbs.

25% W.P.

25% W.P.

301% W.P.

1 tbs.

1 tbs.

41/2 tsp.

2% Granules

When only a few plants or
insects are involved,
they can be hand picked.

Most troublesome on flower
buds. Treat promptly as
small larvae are much
easier to kill than large
ones; occasional specimens
can be hand picked.

Occasional specimens can
be hand picked.

Weeds and annual flowers
are also hosts for spider
mites. Destroy or treat
neighboring hosts to prevent
reinfestation. Usually feed
on lower leaf surface,
sprays should be so
directed. Make two ap-
plications 5 to 7 days apart.

*These compounds are sold under several names. Several general purpose mixtures are available which contain 2 or more of
the above insecticides and miticides. Also, fungicides are included in many general purpose sprays.
**WP = Wettable Powder; EC = Emulsifiable Concentrate (Liquid). The most commonly available formulations are given.
Other formulations are available. Follow label directions!
***A spreader-sticker should be added to all spray mixtures.


Amount/25 sq ft
Pesticide* Formulation When to apply of soil surface Procedure



Water soluble
liquid, 33%
active ingredient.

17 '

50% EC****

3 to 4 weeks before
planting or longer
if soil is cold or
very wet. Soil must be
between 60 and 90F
at 3 inches deep when
SMDC is applied.

At time of

7 to 14 days
before planting
or at least 12
months after

/2 pt.

5 ozs.

1 tbs.

Prepare soil as outlined.** The required amount
of SMDC can be applied with a sprinkling can
(mix each pint of SMDC in at least 2 gallons of
water and sprinkle uniformly over the area), a
hose proportioner (mix each pint of SMDC with 3
pints of water and apply to the area uniformly
with a hose proportioner), or a rotary tiller
(spray or sprinkle diluted SMDC immediately in
front of tiller and follow tiller with a roller
to compact and seal the soil). Immediately
after application, sprinkle with water until
soil surface is sealed or cover with a plastic
tarp for 48 hours.
Prepare soil as outlined.** Sprinkle granules
uniformly over the area, then mix them into the
top 4 to 6 inches of soil. Wet the soil to the
depth to be treated.***
For preplant use, prepare soil as outlined.**
Before treating established roses, loosen the
soil in the root zone as much and as deeply as
possible without damaging roses. Liquid DBCP
may be applied in the same ways that SMDC is
applied. Immediately afterward, irrigate with
enough water to wet the soil to the depth to
be treated.***

For roses planted 6 1 tbs.
to 12 months ago.

*Other pesticides useful for control of nematodes in roses are restricted to use by qualified personnel for commercial use only.
Among these are Temik and Vorlex. For more information, contact the office of the Florida Cooperative Extension Service in
your county.
**Preparation of soil: Thoroughly till the soil to the depth to be treated at least 1 week before application. Break up all clods
and remove undecomposed plant roots. Wet the soil to the depth to be treated (at least 1 ft.) a week before application, after
it has been prepared as described.
***In very sandy soils, 1 inch of water (15 gallons/25 sq ft) will wet the soil to about 12 inches deep; finer textured soils require
****Other concentrations of DBCP may be available; read the label and adjust the dosage accordingly.

Abbreviations used on the preceding pages are:
WP-Wettable powder
EC-Emulsifiable concentrate
sq ft-square feet


Fungicide Amount/gallon
Diseases Description sprays of water* Remarks

Black spots or patches
with irregular or fea-
thery margins on leaves.
Leaves turn yellow and
fall from plant.



Whitish irregular blot-
ches on leaves, twigs
and flower buds. Roll-
ing or distortion of
leaf edge. Infected
areas covered with pow-
dery growth.


1 lb/100 gal Remove infected and fallen leaves.
(% tbs/gal) Spray at weekly intervals;
use sprayer that will produce fine
12 oz mist and adequate pressure for
100 gal covering both leaf surfaces thoroughly
(% tbs/gal) and uniformly. Bi-weekly applications
of Daconil or Benlate should be
1 V1 lb/100 gal adequate except during periods
(1 tbs/gal) of frequent rainfall or when
infection is heavy.
1% lb/100 gal
(% tbs/gal)

Daconil 2787
(75 W)
benomyl (50 W)

Phaltan (75 W)

Fore (80 W)

Actidione PM

benomyl (50 W)

Sulfur wettablee)

12 oz
100 gal
(% tbs/gal)
4-6 lbs/100 gal
(2 tbs/gal)

Brown spots with gray
centers, regular

Effective as a mildew eradicant.
Can be used to clean up heavy
infection. Four to 6 applications at
weekly intervals usually sufficient.
Repeat if mildew again becomes
a problem.

Spray at weekly intervals when
mildew is a problem. Do not apply
if temperature will exceed 850F.
This disease is most serious on
poorly grown plants. Improve
growing conditions. Regular
spraying for black spot usually

3 lb/100 gal
(2 tbs/gal)

Fungicide Amount/gallon
Diseases Description sprays of water* Remarks


zineb (75% WP)

zineb (75% WP)

Somewhat rounded galls,
with rough, irregular
surfaces on stems near
ground line, on roots,
occasionally on aerial
Light yellow spots, sur-
rounded by green halo
on upper leaf surface.
Powdery reddish orange
masses of spores formed
on lower leaf surface.
Browning and dying of
leaves, often from
edges. Large irregular
blotches. May show gray
fungal growth on under-
side of leaves during
periods of very high
humidity. Reddish
streaks on flower stems.
Browning or blackening
of stems and dying back
from tip or pruning cut.
Sometimes wilting of

1%-2 lbs/100
(l-1/: tbs/

1%-2 lbs/100
(1-1 tbs/

4 lbs/100 gal
(2 tbs/gal)

Control by exclusion. Plant only
gall-free new plants. Remove
infected plant, dig out
surrounding soil and replace
with new. Use plants grafted
on Rosa fortuniana.
Remove infected leaves. Spray
at weekly intervals as long as
disease is a problem.

Remove infected leaves if practical.
Spray at 5-7 day intervals
as long as disease is a

Remove by pruning, cutting well
below infected wood. Paint cut
with pruning compound. Spray plants
with basic copper sulfate following
any major pruning, especially
after late winter pruning.

basic copper
sulfate (48-
53%; )




Fungicide Amount/gallon
Diseases Description sprays of water* Remarks

CANKER Localized diseased areas Same as DIEBACK. A regular spray
on stems. Gray lesions program for black spot control
with reddish, regular will help keep these diseases
margins or indefinite in check.
light brown areas.
MUSHROOM Slow or rapid dying of Remove and destroy plant and as
ROOT ROT part or all of plant. much of the root system as possible.
Layer of white fungal Remove soil of root area (without
growth between bark and scattering) and dispose of or treat it to
wood primarily in upper destroy fungus. Treat sides and
roots and lower stem. bottom of hole with Vorlex
(commercial growers) or
SMDC (Vapam, VPM) and refill
with uninfested soil.

Rose spraying should be done carefully. Follow recommendations. Measure pesticides accurately.
Plant injury may occur from the use of a pesticide. Some varieties are more sensitive than others.
If injury is excessive, reduce pesticide rate or try other materials.
*A few drops of wetting agent or spreader-sticker may be added to a spray solution to improve wetting of plant foliage and
distribution of pesticide.
Do not add wetting agents to Phaltan sprays.

Single copies are free to residents of Florida and may be
obtained from the County Extension Office. Bulk rates are
available upon request. Please submit details of the re-
quest to C.M. Hinton, Publication Distribution Center,
IFAS Building 664, University of Florida, Gainesville,
Florida 32611.

This public document was promulgated at an an-
nual cost of $1,657.47, or 11 cents per copy to
inform rose growers on diseases and insects in

Universit of Flor


(Acts of May 8 and June 30, 1914)
Cooperative Extension Service, IFAS, University of Florida
and United States Department of Agriculture, Cooperating
K. R. Tefertiller. Director

University of Florida Home Page
© 2004 - 2010 University of Florida George A. Smathers Libraries.
All rights reserved.

Acceptable Use, Copyright, and Disclaimer Statement
Last updated October 10, 2010 - - mvs