• TABLE OF CONTENTS
HIDE
 Copyright
 Front Cover
 Table of Contents
 Introduction
 Location and soils
 Varieties
 Sources of bulblets
 Hot-water treatment
 Preparation of bulblets for...
 Preparation of bulbs for plant...
 Preparation of soil for planti...
 Methods of planting bulblets
 Culture of planting stock
 Fertilization
 Control of weeds
 Drainage and irrigation
 Sanitation
 Frost and wind damage
 Control of wireworms
 Diseases and other disorders
 Spraying
 Harvesting
 Curing and grading bulbs
 Bulb yields
 Prepation of bulbs for storage
 Back Cover






Group Title: Bulletin - University of Florida. Agricultural Experiment Station - no. 664
Title: Gladiolus corm production in Florida
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027491/00001
 Material Information
Title: Gladiolus corm production in Florida
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 47 p. : ill. ; 23 cm.
Language: English
Creator: Magie, R. O ( Robert O )
Overman, Allen R., 1937-
Waters, W. E ( Will E )
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1964
 Subjects
Subject: Gladiolus   ( lcsh )
Corms   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: R.O. Magie, A.J. Overman, W.E. Waters.
General Note: Cover title.
Funding: Bulletin (University of Florida. Agricultural Experiment Station) ;
 Record Information
Bibliographic ID: UF00027491
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: aleph - 000929046
oclc - 18353565
notis - AEN9810

Table of Contents
    Copyright
        Copyright
    Front Cover
        Page 1
    Table of Contents
        Page 2
    Introduction
        Page 3
        Page 4
    Location and soils
        Page 5
    Varieties
        Page 5
    Sources of bulblets
        Page 6
    Hot-water treatment
        Page 7
        Page 8
        Page 9
    Preparation of bulblets for planting
        Page 10
    Preparation of bulbs for planting
        Page 11
    Preparation of soil for planting
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
    Methods of planting bulblets
        Page 21
    Culture of planting stock
        Page 22
        Page 23
    Fertilization
        Page 24
        Page 25
        Page 26
    Control of weeds
        Page 27
    Drainage and irrigation
        Page 27
    Sanitation
        Page 28
    Frost and wind damage
        Page 29
    Control of wireworms
        Page 29
    Diseases and other disorders
        Page 30
    Spraying
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
        Page 36
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
    Harvesting
        Page 42
    Curing and grading bulbs
        Page 43
        Page 44
    Bulb yields
        Page 45
    Prepation of bulbs for storage
        Page 45
        Page 46
        Page 47
    Back Cover
        Page 48
Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida




February 1964


Revised. See no.
664-A ^ I ^ 44









Gladiolus

Corm

Production

in Florida


R. O. Magie


A. J. Overman


Agricultural Experiment Stations
university of Florida. Gainesville
J. R. Beckenbach. Director


Bulletin 664


W. E. Waters

















CONTENTS
Page

INTRODUCTION ........................................... 3
LOCATION AND SOILS .........................................................................----------......... 5
VARIETIES .-...............-.......................------.... 5
SOURCE OF BULBLETS .......................................-----. ------ 6
HOT-WATER TREATMENT ....-.-.......................-------- ------- 7
PREPARATION OF BULBLETS FOR PLANTING ....................----------------.---. 10
PREPARATION OF BULBS FOR PLANTING ......----............----------------------- 11
PREPARATION OF SOIL FOR PLANTING ......................---------------------------- 12
METHODS OF PLANTING BULBLETS ............ ---........-----------------------...... 21
CULTURE OF PLANTING STOCK .........................-.. ---------. .----- 22
FERTILIZATION .................--..----.. ---- ---------------------- 24
CONTROL OF W EEDS ............................................ ......... 27
DRAINAGE AND IRRIGATION .....................-- ------------ ------- --...... 27
SANITATION ..........---.......-----.. -------------------------- 28
FROST AND WIND DAMAGE ...............--......----- ------- ------------- 29
CONTROL OF WIREWORMS ......................... .--- .---------------- 29
DISEASES AND OTHER DISORDERS .........................------....-----------........ 30
SPRAYING ......................... ---........................ 31
HARVESTING .......---................ ------ ----- ---------- --------------- 42
CURING AND GRADING BULBS .................................--------.---- 43
BULB Y IELDS ...........................-.................................. -- ................ 45
PREPARATION OF BULBS FOR STORAGE ....................... ....... .................. 45











To simplify the information in this bulletin it is sometimes necessary
to use trade names of products. No endorsements of named products are
intended nor is criticism implied of similar products which are not men-
tioned.









GLADIOLUS CORM PRODUCTION

IN FLORIDA

R. O. MAGIE, A. J. OVERMAN, AND W. E. WATERS


INTRODUCTION

Gladiolus flower growers need a continuous supply of healthy
bulbs 2 in order to obtain high yields of excellent quality flowers
year after year. Some bulbs have been grown from bulblets in
Florida for several years; however, prior to the advent of hot-
water treatment of bulblets many of the plantings were fre-
quently severely damaged by diseases. Also, bulb production
from bulblets is generally unsatisfactory on farms that special-
ize in flower production. Therefore, the flower growers have
relied on bulbs produced in northern and western United States
and Holland. Presently an estimated 50 million bulbs are pur-
chased annually for use in Florida. By adhering to the recom-
mended procedures (Fig. 1), Florida growers can compete suc-
cessfully in this market.
Several factors favor the production of healthy gladiolus
bulbs in Florida. (1) Summer-harvested bulblets can be treated
effectively in hot water for disease control; whereas, those dug
in cool soils will not usually tolerate the high temperatures re-
quired for disease control. (2) Summer-harvested bulbs are
dormant enough to be stored several months longer than similar
bulbs from cool soils. (3) Spread of virus diseases in gladiolus
is not a major problem in Florida, even though bulbs infected
with cucumber mosaic, virus stunt, and western aster yellows
have been introduced frequently. (4) Florida is the major source
of bulbs that may be planted in the fall for winter flower pro-
duction; whereas, bulbs from other sources are usually dug in
the fall and planted in the winter.
Many factors are involved in successful bulb production in
Florida. Among these are (1) location and time of planting,
(2) choice of varieties, (3) handling of bulblet stocks, (4) soil
management, and (5) pest control. The availability of ready
1 Pathologist, Assistant Soils Microbiologist, and Assistant Horticultur-
ist, respectively, Gulf Coast Experiment Station, Bradenton, Florida. The
authors acknowledge the assistance of Charlotte Stanton with artwork.
2 Not a true bulb but a corm, the bulbous base of a stem. The term
"bulb" is used here as it is in the trade.







Florida Agricultural Experiment Stations


PLANTED
North Florida: Feb. Mar.
Peninsular : Oct. Nov.


Fig. 1.-Seasonal steps in propagating glaaiolus bulbs from bulblets.







Gladiolus Corm Production in Florida


markets for quality bulbs encourages growers to control all of
these operations carefully.

LOCATION AND SOILS
Bulbs can be grown from bulblets in most sections of Florida
and in most soil types. Full sun is required. In frost-protected
locations bulblets are planted in October and November and har-
vested seven to eight months later. In other locations bulblets
may be planted about three weeks before the average date of
the last frost, or from January 15 to March 15. If frost kills
the young leaves, the plants may recover to produce a good crop,
because the growing point lies below the soil surface. In areas
with little frost protection bulbs should be planted three or four
weeks later than bulblets because they emerge sooner and may
be damaged. In all locations bulbs and bulblets may be planted
later in spring or summer and harvested in early winter.
The most important consideration in choosing land for grow-
ing bulbs is whether gladiolus was previously grown in the soil.
If a previous crop was grown, the soil should be fumigated to
control diseases and volunteer bulblet plants as well as nema-
todes and weeds. The next most important factors to consider
are weed control and soil moisture. New land with few weed
seeds is preferred for growing bulblets. Overhead irrigation and
well-drained soils help insure good germination and growth from
bulblets.
Sandy and sandy loam soils are generally preferred to certain
clay soils which occur in some areas of northern Florida, because
clay tends to cling to bulbs and makes harvesting more difficult.
Bulblets from muck soils and those from bulbs given high nitro-
gen nutrition are less dormant and may not tolerate the standard
hot-water treatment. Bulbs grow very well in muck soils, but
flower growers discriminate against muck-grown bulbs because
they are often more susceptible to diseases than those grown in
mineral soils. High nitrogen nutrition increases susceptibility
to Fusarium and certain other diseases.

VARIETIES
Varieties most in demand are those grown in Florida for com-
mercial production of flowers. A listing of varieties used on one
farm seldom is the same as that on another farm, and the quan-
tity needed of any variety changes from year to year. Plantings







Gladiolus Corm Production in Florida


markets for quality bulbs encourages growers to control all of
these operations carefully.

LOCATION AND SOILS
Bulbs can be grown from bulblets in most sections of Florida
and in most soil types. Full sun is required. In frost-protected
locations bulblets are planted in October and November and har-
vested seven to eight months later. In other locations bulblets
may be planted about three weeks before the average date of
the last frost, or from January 15 to March 15. If frost kills
the young leaves, the plants may recover to produce a good crop,
because the growing point lies below the soil surface. In areas
with little frost protection bulbs should be planted three or four
weeks later than bulblets because they emerge sooner and may
be damaged. In all locations bulbs and bulblets may be planted
later in spring or summer and harvested in early winter.
The most important consideration in choosing land for grow-
ing bulbs is whether gladiolus was previously grown in the soil.
If a previous crop was grown, the soil should be fumigated to
control diseases and volunteer bulblet plants as well as nema-
todes and weeds. The next most important factors to consider
are weed control and soil moisture. New land with few weed
seeds is preferred for growing bulblets. Overhead irrigation and
well-drained soils help insure good germination and growth from
bulblets.
Sandy and sandy loam soils are generally preferred to certain
clay soils which occur in some areas of northern Florida, because
clay tends to cling to bulbs and makes harvesting more difficult.
Bulblets from muck soils and those from bulbs given high nitro-
gen nutrition are less dormant and may not tolerate the standard
hot-water treatment. Bulbs grow very well in muck soils, but
flower growers discriminate against muck-grown bulbs because
they are often more susceptible to diseases than those grown in
mineral soils. High nitrogen nutrition increases susceptibility
to Fusarium and certain other diseases.

VARIETIES
Varieties most in demand are those grown in Florida for com-
mercial production of flowers. A listing of varieties used on one
farm seldom is the same as that on another farm, and the quan-
tity needed of any variety changes from year to year. Plantings







Florida Agricultural Experiment Stations


of each variety should be revised yearly according to the needs
of the market.
Approximately 28 percent of the flower production is from
white varieties, mainly 'June Bells', 'White Excelsior', and
'White Friendship'; 27 percent from pink varieties, predom-
inately 'Spic and Span', 'Friendship', and 'Traveler'; 20 percent
from red varieties, principally 'Valeria'; 10 percent from yellow
varieties, primarily 'Hopmans Glory'; 10 percent from lavender
and rose varieties, mainly 'Elizabeth the Queen', 'Rose Spire',
'Wild Rose', and 'Van Zantens Glory'; and 5 percent from varie-
ties of other colors.

SOURCE OF BULBLETS

Bulbs are propagated from bulblets which grow in clusters
at the base of maturing bulbs (Fig. 2). Bulblets are usually
graded into four sizes: large-over 3/8 inch diameter; medium-
1/4 to 3/8 inch; small-3/16 to 1/4 inch; and very small-less
than 3/16 inch (Fig. 3). Bulblets may be as large or larger
than small bulbs (Fig. 2). The number of bulblets per bushel
ranges from 25,000 to 40,000 for large size; 40,000 to 100,000 for
medium; 100,000 to 150,000 for small; and as many as 250,000
for the very small size. The weight of bulblets per bushel aver-
ages 45 pounds.
STEM
I NEW BULB


BULBLETSS
---OLD BULB
NE i ? CONTRACTILE
BULB ROOTS







S"c- -,. (C 6= 2JYEAR
PLANTING FLOWERING
BULBLETS STOCK STOCK
9 SMALL d NO 6 NO 3
g MEDIUM o g o CJ 2
LARGE 4 4 I

Fig. 2.-Vegetative reproduction of gladiolus. c JUMBO







Gladiolus Corm Production in Florida


Fig. 3.-Revolving cage for sorting bulblets into various sizes.
Trash is deposited from the lower end.

Bulblets may be purchased from flower growers or from
other bulb growers. Arrangements to purchase them should
be made before harvesting begins. In order to find the best
stocks available, the fields should be inspected while plants are in
bloom to determine virus disease content and variety purity.
Bulb growers should save bulblets for propagation only from
their best stocks.
Bulblet stocks should be chosen carefully, since disease or-
ganisms which occur in the parent bulbs also may occur in the
bulblets. These organisms include viruses, fungi, and rootknot
nematodes. One method of obtaining a good stock of any va-
riety is to collect bulblets from several sources, keeping each
stock separately identified. The best of these stocks, chosen for
variety purity, health, and flower production, should be used for
future propagation and gradually improved by roguing. When-
ever possible, bulblets should be obtained from "mother" blocks.
To grow quality bulbs, it is also necessary to use hot water-
treated bulblets.

HOT-WATER TREATMENT
The hot-water treatment reduces the disease organisms, in-
sects, and nematodes carried in the bulblets. The treatment is







Florida Agricultural Experiment Stations


more effective against Curvularia and Stromatinia disease in-
fections than against Fusarium infection. The latter has not
been eliminated from bulblets even in carefully controlled tests.
The "corms" of nut-grass weeds, commonly carried from field to
field with gladiolus bulblets, are usually reduced by the treat-
ment.
The hot-water treatment is a 30-minute soaking in water
held at the highest temperature which the bulblets or small bulbs
can survive. The high temperatures of the hot-water treatment
are needed to control the Fusarium fungus carried in bulblets
and bulbs as latent infections. The high degree of dormancy
required for bulbs and bulblets to tolerate high temperatures is
developed best in those grown and harvested in warm weather.
Small bulblets and small bulbs tolerate the heat treatment better
than large ones. Intact bulblets withstand the hot water much
better than cracked or shelled bulblets. Planting stock bulbs
have been successfully treated, but should first be tested as sug-
gested below.
Preliminary Test.-A preliminary test should be made on
small samples of bulblets or bulbs about two weeks before they
are to be treated. Bulblets need to be soaked in cool water for
two days just before testing. Using a laboratory water bath or
other device to hold constant temperature, soak a handful of
bulblets or bulbs wrapped in mesh bags or cheesecloth for 30
minutes at 1360 F and another handful at 1330 F. Cool them
quickly and hold in a warm, moist place at least five days. If the
sample bulblets or bulbs treated at 1360 are white and firm, treat
the rest at this temperature. Superficial browning of bulb may
not affect growth if the bulb remains hard. If the interior of
many bulbs or bulblets turns brown or soft after treatment at
1360 and those at 133 remain white and firm, treat the entire
lot at 133 F. The lower temperature is generally effective
against nematodes, Curvularia, and Stromatinia. The best tem-
perature is the one that will kill not more than 10 to 20 percent
of the bulblets. Small bulblets with tight husks should be treat-
ed at 137 to 139 for best results. Those temperatures are usu-
ally safe with bulblets harvested in hot-weather and handled as
recommended.
Bulblets or bulbs, held loosely in suitable containers, may be
treated in any water tank with a steady source of heat, provided
that (1) the water is pumped or forced vigorously so as to flow
through the bulblets continuously, (2) the heat source can be
regulated to hold the desired temperature within 10 F, and (3)







Gladiolus Corm Production in Florida


the temperature is checked by the attendant every 5 minutes,
using accurate thermometers hung in two or more locations in-
side the tank. The Bureau of Plant Industry of the Florida De-
partment of Agriculture maintains equipment to treat growers'
bulblets at central locations. The Department has excellent hot
water tanks for this service.
Each step of the treatment procedure is important:
1. Use bulblets or bulbs harvested May through October
in Florida or similar climate. In southern Florida
bulblets harvested in November or during March and
April have been successfully treated, but the prelim-
inary test should always be made when harvesting
occurs in a cool month (average temperature below
70 F).
2. Hold bulblets in warm air (preferably between 75 and
850 F) for two to three months following harvest.
Make a preliminary test in hot water with small sam-
ples.
3. Two days before the treatment, cover the bulblets with
water and discard the floaters, which consist mainly
of diseased and injured bulblets. Many of the good
ones will also float if they were excessively dried.
Place the good bulblets in screen boxes or mesh sacks,
one-half to two-thirds filled, and soak in water for two
days. Screen boxes are preferable to bags for treat-
ing bulblets. Soaking is not necessary for bulbs.
4. About one-half hour before the box or bag is to be
placed in the hot water tank, attach a numbered float
and place the package of bulbs or bulblets in a tank
of warm water (100 to 1100 F). (The warm water
soak is not necessary unless the bulblets were soaked
in cold water.) The number of floats required equals
the number of packages accommodated by each tank.
The floats are numbered consecutively so that one
package at a time may be added to the tanks and re-
moved in the same order. If there are six packages
in one tank at a time, remove the one which has been
treated 30 minutes and add a new one every five min-
utes. With 10 packages in the tank, remove and add
one every three minutes. Two sets of floats are re-
quired when bulblets are placed in warm water before
the hot water treatment.






Florida Agricultural Experiment Stations


5. Submerge bulblets or bulbs in the hot water for 30
minutes. Hold the water as closely as possible to the
temperature which was found to be relatively safe in
the preliminary test. Turn bags frequently if flow of
water is uneven.
6. As each package is removed in order from the hot wa-
ter, plunge it into water which is cooled by fresh water
running continuously into the container. After 20
minutes or more, remove package from cool water and
drain.
7. Dry bulblets in seed driers with warm air or pour them
in thin layers in sterilized trays with screen bottoms
and dry them thoroughly with fans. Unless layers
are very shallow, turn bulblets several times to expose
wet bulblets to air. Dry bulbs in partly-filled, treated
trays or in seed driers. (Trays may be "sterilized"
in hot water or as suggested in section on sanitation.)
8. Dry bulbs and bulblets thoroughly prior to cold stor-
age. Place bulbs in cold storage within two weeks
after treatment; bulblets within three or four weeks.
Do not allow depth of bulbs or bulblets to be over 2
to 3 inches in storage trays, especially when they are
to be stored for more than four to six weeks. Do not
store in sacks because trapped moisture may result
in mold growth and dead bulblets.

PREPARATION OF BULBLETS FOR PLANTING
Hot-water-treated bulblets should be stored at 35 to 450 F
for a period of four months or more to break dormancy prior to
planting. If the desired planting date is less than four months
after the hot-water treatment, samples should be tested for germ-
ination after eight to 10 weeks in cold storage. Whenever pos-
sible, during the three weeks just before planting, bulblets
should be held in a warm room to condition them to sprout
promptly. Care must be taken to allow movement of air through
the bulblets which are held in screen-bottom trays. A tempera-
ture of 800 F and a relative humidity of 80 percent are very
effective in accelerating development of root swellings and
sprouts. Smaller bulblets seldom show root swellings, but when
they show on larger bulblets, the smaller'ones of the same lot
are usually ready to plant.
Bulblets should be soaked in cool water for two days just






Gladiolus Corm Production in Florida


prior to planting. A water-resistant label is put inside the bag
and another is attached to the outside of each bag for identifica-
tion. After draining overnight, bulblets should be soaked one
hour in 2 pints of Elcide 73 per 100 gallons water plus 11/2
ounces (3 tablespoons) Triton X-100 and drained overnight be-
fore planting.
The Elcide solution must be kept in a clean tank and made
up fresh each day. In order to control rootknot nematodes car-
ried in bulblets that were not hot-water-treated, soak them 15
minutes in a parathion dip one day prior to the Elcide dip treat-
ment (see Table 1).
Instead of placing bulblets in a warm room for several weeks,
some growers keep them moist, but well aerated, until roots be-
gin to appear. Bulblets may be held in bags or trays, in shallow
layers, and sprinkled daily. Examine every other day for signs
of sprouting; have soil ready to plant. Bulblets are then treated
with Elcide 73 and planted immediately. If 5 percent or more
of the larger bulblets show root swellings, they should not be
held wet for more than three days.

PREPARATION OF BULBS FOR PLANTING
Bulbs should not be planted unless most of them show signs
of breaking dormancy, because susceptibility to diseases and soil
pests is increased by planting dormant bulbs. One of the first
signs of dormancy breaking in large bulbs is the swelling of the
small bud near the base (Fig. 4). When harvested in warm
weather, bulbs do not break dormancy for several months un-
less placed in cold storage for several weeks and then held in
warm air for about two weeks. Cold weather bulbs may show
signs of root growth before they are placed in cold storage.
Temperatures of 70 to 800 F and a relative humidity of 60 to
70 percent are effective in accelerating root development. Gen-
erally, large bulbs develop root buds one to two weeks after re-
moval to warm air, but small bulbs may require three to four
weeks.
Roots develop first on bulbs near the center of the tray or
box, where the humidity tends to be highest. Air should move
through the bulb masses continuously to prevent premature root-
ing on bulbs removed from storage. The enclosed bulbs should
be examined three times per week in sample t-ays so that at
the first signs of soft root growth the bulbs may be poured into
shallow layers or planted. The goal is to develop hard root swell-







Florida Agricultural Experiment Stations

TABLE 1.-BULB TREATMENT CHART.


Kind of Stock Treatment After Harvest


Bulblets
Cure two to three months at 75-85 F. Treat in
hot water at highest safe temperature. (See sec-
Planting stock bulbs tion on hot water treatment.) Then break dorman-
harvested in spring, cy in cold storage.
summer, or fall


Small and large Within one day after harvest dip 20 minutes in
bulbs not treated in 5 lbs. Thylate + 5 lbs. Captan Seed Protectant +
hot water 1 pt. parathion EC4** + 2 qts. Plyac per 100 gals.
water. Captan Seed Protectant may be used alone
as a dip at 7 lbs. per 100 gals. water. Captan may
be used as a dust to coat the bulbs; the concentra-
tion of captain in the dust should be 10 to 15 per-
cent.

Dowicide B dip is often used on large farms instead of captain or captain
+ Thylate. Dowicide B is available in 100 lb. drums. Use 12 lbs. per 100
gals. water for post-harvest dip; use 2 lbs. per 100 gals. water for pre-
storage treatment; or use 4 lbs. per 100 gals. water for pre-planting dip.
All dips are for 20 minutes. Parathion EC4 may be added as recommended
with captain. Dowicide B is superior to captain or captain + Thylate in
that it is less expensive and makes a true solution (does not need to be
stirred off the floor of the vat); however, Dowicide B tends to delay sprout-
ing 2 or 3 days and can be used either before or after storage, not both
times.

ings without soft roots. Before planting, treat bulbs as recom-
mended in Table 1, if not adequately treated previously.

PREPARATION OF SOIL FOR PLANTING
In order to produce a healthy crop of bulbs, the hot-water-
treated bulblets should be set in soil free of disease organisms,
nematodes, and weeds which damage gladiolus. Though land
may be "new" to gladiolus and free of Fusarium and Stromatinia
disease, previous crops or the native cover may have contributed
populations of weeds, diseases, and nematodes that complicate
bulb production. Soil pests must be controlled before planting,
because there is little that can help a crop after it has become
infected with soil-borne diseases and nematodes. Even though
bulb production may proceed normally during the season, root-







Gladiolus Corm Production in Florida


Treatment Just Before Planting

Dip for one hour in Elcide 73 just before planting, using 2 pts. of Elcide
73 per 100 gals. water. Use clean tank and make fresh solution each day
of use.

Dip for 20 minutes in 5 lbs. Thylate + 5 lbs. Captan Seed Protectant per
100 gals. water. Keep powders stirred into suspension. Hold bulbs in
trays, not in bags which strain out the powders. Dowicide B* may be
used instead of the Thylate + Captan mixture.

If not treated after harvest, dip bulbs for 20 minutes in 5 lbs. Thylate +
5 lbs. Captan Seed Protectant 1 pt. parathion EC4** per 100 gals. water.
(Plyac is not needed as "sticker" when treated bulbs are not to be stored
and not handled dry.) Bulbs treated after harvest with Thylate + Cap-
tan + parathion may be dipped in Dowicide B* before planting. The
double treatment is recommended only for old stocks of susceptible varie-
ties and those grown on "diseased" soil.


** Parathion emulsifiable, xylene-base concentrate, 4 lbs. active ingredient
per gallon. Do not use the water-base (flowable) parathion concentrate.
One-half pint of parathion EC8 would be equal to 1 pt. of EC4. Whenever
the dip is re-used an additional day, add another pint of parathion EC4
for each 100 gals. of dip preparation. Follow the manufacturer's directions
and precautions regarding the use of parathion. Monthly blood tests for
workmen, starting before contact with chemical, are advised. Only re-
sponsible, trained workmen should be allowed to handle parathion or work
around the dip mixture. To reduce the hazard of disposing of the parathion
dip, stir in 4 lbs. of hydrated lime per 100 gals. before dumping into a ditch.

knot nematodes may invade the tissue of the new bulb and be
carried through curing and storage to affect crop growth the
following season. Therefore, some type of preplanting soil fumi-
gation is generally necessary.
Management Practices.-Certain management practices can
preserve the production value of gladiolus land. Regardless of
whether chemical soil treatment is to be used, growers should
control soil conditions of the field for as long before the planting
date as possible. Plowing and disking to clean-fallow the soil
for at least two months prior to planting will starve out many
organisms that attack gladiolus. Moisture should be maintained
in the soil during this period to germinate weeds, which are then
killed by cultivation. Moisture and cultivation also assist in
rotting old plant debris, which harbors many plant pests.







Florida Agricultural Experiment Stations


Soil Fumigation.-Where soil fumigation is to be used, all
handling of the soil should be completed before time to treat.
Drainage, irrigation, and roadways should be established. Soil
amendments should be applied several months before planting
time, and seedbed tilth and moisture should be maintained con-
sistently for at least two weeks before fumigation. At the time
the fumigant is applied, fertilizer may be included as the bed is
formed. The soil should not be disturbed after placement of the
fumigant. This is important in order to obtain maximum bene-
fit from the chemical.
At the time that the need for fumigating the soil is estab-
lished, growers must make several decisions: (1) which pests
must be controlled; (2) which chemical is to be used; (3) which
planting pattern is to be used for the crop, since the placement
of the chemical depends on how gladiolus are to be planted; and
(4) which method of application is suitable. Choice can be made
from the recommendations found in Table 2. Since so many
factors influence the results obtained with any fumigant, precau-
tions to be observed during preparation of the soil for treating
and planting are included for the growers' convenience (Table 3).






















Fig. 4.-Bulbs ready to plant. Root "buds" are well-developed. Ar-
rows point to swollen shoot buds near base of bulbs. Swelling of these un-
covered buds may be the first sign that dormancy is broken.







Gladiolus Corm Production in Florida 15





R,
Illl~~rrl;~.. glow1


/


kii


- w


Fig. 6.-Two-row bed press used to shape and firm soil for
in-the-row fumigation.








16 Florida Agricultural Experiment Stations


TABLE 2.-SOIL FUMIGATION PROCEDURES.

Pests Material Rate Method* Waiting
Controlled Period
Methyl 3 Ibs. per Gas released under plastic 48 hours
bromide 100 sq. ft. cover.




Vapam Broadcast as a drench in 1:5 2 weeks in
(VPM) dilution followed by %/ inch warm, dry
75 gals. overhead irrigation. weather;
per acre Injected in bands 6 inches 3 weeks in
Fungi, apart 5 inches below finished cold, wet
Nematodes (compact) bed. weather.
Weeds 1% pts. Injected in single band 5
per 100 ft. inches below planned crop
furrow row. Soil compacted.
300 lbs. Broadcast and rototilled to
active depth of 6 inches followed by
Mylone per acre /4 inch overhead irrigation. Same as
% lb. ac- Single band in planned crop Vapam
tive per row 6 inches below surface
100 ft. of compacted beds.
furrow

50 gals. Broadcast. Injected in
per acre streams 8 inches apart
Vorlex 6 inches below compacted Same as
surface. Vapam
1 pt. per Injected in single band 8
100 ft. inches below planned crop
furrow row. Soil compacted.
Fungi, Allyl 25 gals. Broadcast as a drench in 3 days
Weeds alcohol per acre 1:200 dilution.


Nematodes


Ethylene
dibromide
(EDB W85)


6 gals.
per acre

1% oz.
per 100 ft.
furrow


Injected in bands 12 inches
apart 8 inches below com-
pacted soil surface.
Injected in single stream 8
inches below planned crop
row. Soil compacted.


10 days in
warm, dry
weather;
3 weeks in
wet, cold
weather.


The benefits derived from Vapam, Mylone, Vorlex and EDB should be insured in warm
weather by daily overhead irrigation with % inch water for the first 3 days following soil
treatment or by covering the soil for 5 days with a plastic sheet.







Gladiolus Corm Production in Florida


Advantages Disadvantages For
Bublets Bulbs
Excellent control of glad- Hazardous to handle. Cannot be Yes
iolus pests. Short waiting used at temperatures below 50"
period. F. Expensive because hand labor
is required unless special equip-
ment is available to lay plastic
cover.

Excellent control of gladi- Control of soil moisture and com- Yes
olus pests. Less costly action is critical to prevent pre-
than methyl bromide. mature escape of gases from the
soil. In hot weather difficult to Yes
obtain maximum control.

Yes



Formulated as granular ma- Requires moisture to fumigate. Yes
trial for easy handling. Not effective in excessively dry
In hot weather more de- soil.
pendable than Vapam. Yes
Special equipment avail-
able but not required for
application.

Excellent control of gladi- Waiting period may be increased Yes
olus pests. by cold, wet weather following ap-
plication.
Yes



Short waiting period. Does not kill nutgrass. Hazard-
Leaves no toxic residues ous to handle; it is a lachrymator. Yes Yes
in soil.

Low in cost. Excellent Stimulates growth of nutgrass. Yes Yes
nematode control.
Yes






Florida Agricultural Experiment Stations


TABLE 3.-RECOMMENDED MANAGEMENT OF SOIL FUMIGATION.


1. By one or a combination of
the following operations keep
populations of soil pests as
low as possible between glad-
iolus crops: a) clean culti-
vation, b) crop rotation, c)


alternate flooding and drying.


DO destroy plants after harvest. DO remove infected plant
parts from the field where practical.
DO NOT expect these short term cultural operations to re-
place fumigation.


2. Recognize the pests which
must be controlled (fungi,
nematodes, weeds).


/ I DO consult your county ag-
ricultural agent, State Bu-
reau of Plant Industry or Experiment Stations for diagnosis
of problems.
DO NOT assume that abandoning "old" land infested with
nematodes or disease organisms to weeds for several seasons
eliminates the problem.


3. Choose the proper fumigant
for the job.
DO base choice on pests to
be controlled, cost related to
crop value, method of appli-
cation and equipment avail-
able. DO consider desirability of controlling as many pests
as possible in one operation: i.e., money invested in nematode
control can be lost if crop is destroyed by Stromatinia dis-
ease.
DO NOT expect elimination of soil pests with present day
fumigants; rather, expect an economic degree of temporary
control.


e""^ Qlg







Gladiolus Corm Production in Florida


TABLE 3.-RECOMMENDED MANAGEMENT OF SOIL FUMIGATION.
(cont.)


q0
0


4. Prepare soil in advance so
old plant debris will be well
rotted at treatment time.


-- DO establish uniform porosi-
ty to 8-10 inch depth to permit uniform passage of fumigant
vapors through soil.
DO NOT expect fumigant to penetrate deeply into masses of
unrotted plant debris.


5. Add fertilizers and soil con-
ditioners before or at the
same time as the fumigant.


DO complete all operations
except planting by time of treating.
DO NOT mulch area with untreated materials after initial
treatment. DO NOT combine fumigants with other chem-
icals.


6. Maintain a good soil mois-
ture for at least 2 weeks
prior to treatment.


DO wet to surface to encourage germination of weed seed,
spores, sclerotia, and hatching of nematode eggs.
DO NOT waterlog the soil.

7. Test the soil temperature at a 4 inch depth to be sure it is
above 600 F. DO NOT fumigate when soil is below 600 F.

8. Choose the proper method
of application.
DO use in-the-row for widely
spaced crops. DO use broad-
cast for bulblets. DO use
drenches where feasible
when maximum control of disease organisms and weeds are
essential.
DO NOT treat in-the-row shallower than 5 inches or deeper
than 8 inches.


JM
77/\


~li~: I \\\\\'\\'






Florida Agricultural Experiment Stations


TABLE 3.-RECOMMENDED MANAGEMENT OF SOIL FUMIGATION.
(cont.)
9. Use recommended rates of fumigants for the method of ap-
plication to be used.
DO insure maximum benefit of dose by employing a water
seal, soil compaction, or plastic cover (Fig. 6).
DO NOT increase recommended dosage; toxic residues may
injure crop.
S10. Observe proper waiting pe-
riod before planting.
DO increase waiting period
if soil is consistently below
650 F, or if excessive rain-
fall follows treatment. DO
check soil for odor of chemical before planting.
DO NOT plant as long as odor of chemical remains in soil.
DO NOT till soil to dissipate fumigant vapors.

11. Plant disease- and nema-
tode-free bulblets and bulbs.
DO dip diseased and nema-
tode-infected stocks.
DO NOT contaminate treat-
ed area at planting with
plant containers, contami-
nated tools or workers' feet, etc.

12. Retain the treated soil volume during and after planting.
DO recognize boundaries of zone of control so that recon-
tamination can be held to minimum.
DO NOT mix untreated soil into treated soil by breaking
up beds or cultivating deeply.
WITH IN-THE-ROW TREATMENT:
DO plant over injection point. DO press a bulb furrow
in the bed and press bed back together to cover bulbs
(Fig. 7).
DO NOT plant between two lines of fumigant. DO NOT
throw untreated soil on top of the bed.







Gladiolus Corm Production in Florida


TABLE 3.-RECOMMENDED MANAGEMENT OF SOIL FUMIGATION.
(cont.)

WITH BROADCAST TREATMENT:
Do construct beds at time of treatment.
DO NOT expect maximum control if beds are constructed
after treatment.


METHODS OF PLANTING BULBLETS
For row culture, one, two, or three rows are planted per bed.
High beds are not desirable unless drainage is poor. Rows should
run north and south if possible, so that both sides receive full
sun, and should be spaced 8 to 12 inches apart on beds. Fur-
rows should be made in moist soil just before planting. The
moist bulblets may be spread out in a wide, flat furrow (3 to 6
inches) in "new" land and in fumigated soil. A narrower fur-
row may be used where close cultivation is necessary to control
weeds. Usually bulb planters or modified onion-set planters are
used (Fig. 7). Bulblets should be covered with about 3 inches
of soil, which is then leveled and compressed so that bulblets
have a final covering of 2 to 21/2 inches of soil. Where it is diffi-
cult to keep the soil surface moist, bulblets may be covered with
about 5 inches of soil. Before sprouts have grown an inch, some
of the soil should be scraped off, leaving bulblets with about 2
inches of soil cover. This method of culture would be practical
only where mechanized equipment makes level furrows. The
weed-killing spray should be applied to the freshly scraped bed
surface.
About 120 small bulblets (1/4 inch diameter) or 40 large ones
(over %/ inch) are usually planted per foot of 3-inch-wide fur-
rows. About 2 quarts of large bulblets are needed per 100 feet;
or 18 bushels per acre of double row beds on 3-foot centers. Only
8 to 12 bushels of small bulblets are needed for a similar planting.
The number of bulblets per foot of row is increased in propor-
tion to the percentage of dead bulblets found in a sample from
which the husks have been removed.
Good germination of bulblets is obtained by keeping the bed
moist for several weeks after planting. Overhead irrigation
should be applied as frequently as necessary to prevent drying
of the soil surface; or a high water table can be held by seep
ditches and tile. After the first four weeks in plantings of large







Florida Agricultural Experiment Stations


bulblets, or after eight weeks in small bulblet plantings, soil
moisture should be gradually reduced to a moderate level mid-
way through the season and to only a fair moisture level during
the last month of growth.
The soil surface is generally not cultivated except to control
weeds. Soil is swept to the base of larger gladiolus plants in
order to kill weeds, but plants from bulblets would be pushed
over by such cultivation. Chemical or hand weeding is there-
fore necessary on weedy soils.
A less expensive way to grow bulblets is to plant rows closely
in fumigated soil. This intensive culture reduces costs of con-
trolling nematodes, weeds and diseases; also costs of fertilizer
and labor may be reduced. By planting rows 8 to 12 inches
apart on beds 4 feet wide, growers may produce 16,000 to 25,000
bulbs in 100 linear feet of bed. Extra care must be given to
fertilization and control of water where close culture is used.

CULTURE OF PLANTING STOCK
Small bulbs grown for bulb production are generally planted
in one or two rows per bed with rows running north and south.
Depth of planting is 21/2 to 3 inches. The number of bulbs planted
per foot of row varies from 30 in a wide furrow to 18 in a narrow
furrow. The larger planting stock bulbs are planted more thinly,
from 12 to 20 per foot of row. Bins may be used to scatter bulbs
in the furrow (Fig. 8). Bulbs smaller than 3/ inch in diameter
are only strewn, while those larger than 3/4 inch are placed up-
right by hand after being strewn.
The soil should be irrigated to maintain adequate moisture
for good growth, but wet soil should be avoided. Frequent irri-
gations are not needed to increase germination as for bulblets.
A moderate moisture level promoting good soil aeration and a
1 inch dust mulch should be maintained until three weeks before
harvest, when irrigations are ended. Excessive moisture or poor
soil aeration, especially when bulbs are maturing, may lead to
rotting of bulbs.
The control of weeds by cultivation alone is about as difficult
as with bulblets until the third month, when the plants become
strong enough to have' soil worked up into the row. The use of
herbicides is recommended under the section on weed control.
Removal of immature flower heads improves bulb size; how-
ever, one or two florets are usually allowed to open before cut-
ting of stem so that observations of variety purity and of flower







Gladiolus Corm Production in Florida 23


Fig. 7.-Machine for planting bulblets and small bulbs.


Fig. 8.-Bins for distributing bulbs in two furrows for planting.
Furrows are opened by wedges at base.


,"FEW'







Florida Agricultural Experiment Stations


symptoms of virus infection may be made. Off-type and virus-
infected plants are then removed by pulling up the entire plant.
Care is taken to remove bulblets along with the bulb if harvest-
ing machinery will be used to recover all bulblets from soil. Mow-
ing off flower heads to improve bulb size is not recommended un-
less a bulb stock and variety is free or practically free of viruses
which cause troublesome leaf or flower symptoms. These viruses
may be spread from plant to plant by knives and mower blades;
therefore, when going from one variety or stock to another, allow
mower blades to dry off for about an hour, run them in air for
15 minutes, or swab them with denatured alcohol. Discarded
flowers should be removed from the field when Botrytis or Cur-
vularia disease is present.

FERTILIZATION
Liming.-The optimum soil pH for gladiolus is in the acid
range of 5.5 to 6.5. Slowly soluble sources of lime such as dolo-
mite or high calcic lime should be applied, if needed, at least three
months in advance of planting. If the soil is low in magnesium,
dolomite should be applied. Where fast reaction is desired, hy-
drated lime may be used. In soils with a desirable pH, but a low
calcium level, gypsum should be used. A soil test is recommended
well in advance of planting to determine the specific lime needs
of each field. These tests are available through the county agri-
cultural agent's office.
Major Elements.-The fertilization program for gladiolus de-
pends upon several factors, including bulb size, variety, soil type,
and rainfall. Planting stocks and bulblets require more ferti-
lizer than large flowering bulbs. Bulbs have a much larger
stored reserve of nutrients and develop more extensive root sys-
tems than bulblets. More fertilizer is required in light, sandy
soils than on heavier loamy soils. Heavy rains leach much of
the applied fertilizer from sandy soil; therefGae, frequent appli-
cations of moderate amounts of fertilizer are desirable.
Tests on bulblets grown on sandy soils indicate that 250 to
350 pounds of a mixed fertilizer per 1,000 linear feet of bed (with
two to three rows per bed) are necessary during the growing sea-
son. The fertilizer is supplied in about six equal applications.
The first application should be mixed with the beds prior to
planting. The remaining applications may be applied about
every three weeks and after heavy rains (2 inches or more).
The amount of fertilizer needed will depend on the number of







Gladiolus Corm Production in Florida


bulblets planted per acre and the amount of rainfall. During
the first part of the growing season an 8-8-8 fertilizer may be
used; whereas, during the last half of the season the nitrogen
content of the fertilizer should be decreased. Either a 4-8-8
or 6-8-8 is recommended. Generous nitrogen fertilization pro-
duces large bulbs from bulblets, but the trade considers them
less desirable for flower production than large bulbs grown more
slowly from planting stock. Excessive nitrogen fertilization
also increases the severity of Fusarium bulb rot.
Minor Elements.-The minor elements most likely to be need-
ed for gladiolus plantings on sandy soils are boron, iron, and cop-
per. Sufficient quantities of zinc and manganese are usually in-
cluded in fungicidal sprays. Boron deficiency occurs most often
in bulblets and planting stocks. The deficiency appears as a
horizontal cracking of the leaves beginning at the margins and
extending inward toward the midrib, and as a blunt curving
leaf tip (Fig. 9). In some varieties the upper portion of the
new leaves, including the apex, may become translucent, with
the veins growing together. For soils low in boron, the fertilizer
should contain 0.2 percent B203. If boron deficiency occurs,
spray the crop three or four times at one or two-week intervals
with 1.5 pounds of borax or 1 pound of Solubor per 100 gallons
water per acre. Borax or Solubor may be added to the regular
pesticide spray. The total boron applied per season should not
exceed 15 to 20 pounds of borax per acre.
Iron deficiency usually results from a combination of factors
including high soil pH and the accumulation of copper and phos-
phates in the soil. Iron deficiency appears at first as a yellowing
between the veins of new leaves. In severe cases the new leaves
may be completely yellow. Control measures include liming
old land high in copper to pH 6.0 to 6.5 and including 20 to 30
pounds of chelated iron concentrate per ton of fertilizer. If
iron deficiency occurs, the crop may be sidedressed immediately
with 20 pounds of chelated iron concentrate per acre and sprayed
several times at five-day intervals with 1 pound of iron oxalate
(Nu-Iron) per 100 gallons of water.
Copper deficiency may occur in new sand land. The deficiency
is manifest by abnormal wilting of the leaves. New sand land
to be planted in gladiolus requires approximately 20 pounds of
copper sulfate broadcast per acre. Larger amounts will be nec-
essary on heavier soil types. If a deficiency develops after plant-
ing, the crop may be sidedressed with 8 to 10 pounds of copper
sulfate per acre. Copper sprays are harmful to gladiolus plants.







26 Florida Agricultural Experiment Stations


i^t"j
It ^)


, '





V.
I


Fig. 9.-Leaf symptoms of boron deficiency. Blunt, slightly hooked leaf
tips may be the only symptom on less severely affected plants.


A

it







Gladiolus Corm Production in Florida


CONTROL OF WEEDS
Chemical weed control for gladiolus bulblets planted on old
agricultural land is essential. Dacthal at the rate of 18.5 pounds
of 75W powder per acre of treated area is recommended for bulb-
lets and planting stock. The first application should be made
immediately following planting or when the top 2 inches of
the beds are removed (boarded-off) just prior to emergence. The
treatment may be repeated in 8 to 10 weeks.
Diuron is recommended for bulbs of size 4 or larger and
should be applied immediately following planting, or after the
beds are boarded-off, at the rate of 1.25 pounds of diuron 80W
per acre of treated area. A lay-by application of 1.25 pounds
of 80W diuron may also be applied when the spikes first appear.
If no preemergence treatment is applied, 2.5 pounds of diuron
80W may be applied as a lay-by treatment. Lay-by applica-
tion of diuron should be directed to the base of plants.
Dacthal and diuron are more effective when applied to moist
soil; therefore, these herbicides should be applied immediately
following overhead irrigation or rain. Sufficient water should
be applied to wet the upper 3 or 4 inches of soil. Before any of
these herbicides are applied, the field should be freed of all weeds.
The chemicals are effective only against germinating seeds.
These herbicides may be applied with a knapsack sprayer or
with a power sprayer, using not less than 30 gallons of water per
acre of treated area; the sprayer pressure should not exceed
70 pounds per square inch. The spray equipment should be
thoroughly cleaned after use.

DRAINAGE AND IRRIGATION
Good aeration of soil and uniform moisture conditions pro-
mote maximum growth of gladiolus. With seep irrigation the
water table should be held at a uniform level as much as pos-
sible. For sandy soils, this level ranges from about 12 inches
for bulblets to 18 inches for flowering stock. Good soil drainage
is necessary to remove any excessive rainfall before roots are
damaged.
Overhead irrigation is applied as necessary to maintain a
moderate soil moisture. During prolonged dry periods over-
head irrigation is also, applied to seep-irrigated soils in order
to avoid troublesome accumulations of soluble salts in the soil
surface. Excessive salts kill roots when washed down by the
first rainfall.







Gladiolus Corm Production in Florida


CONTROL OF WEEDS
Chemical weed control for gladiolus bulblets planted on old
agricultural land is essential. Dacthal at the rate of 18.5 pounds
of 75W powder per acre of treated area is recommended for bulb-
lets and planting stock. The first application should be made
immediately following planting or when the top 2 inches of
the beds are removed (boarded-off) just prior to emergence. The
treatment may be repeated in 8 to 10 weeks.
Diuron is recommended for bulbs of size 4 or larger and
should be applied immediately following planting, or after the
beds are boarded-off, at the rate of 1.25 pounds of diuron 80W
per acre of treated area. A lay-by application of 1.25 pounds
of 80W diuron may also be applied when the spikes first appear.
If no preemergence treatment is applied, 2.5 pounds of diuron
80W may be applied as a lay-by treatment. Lay-by applica-
tion of diuron should be directed to the base of plants.
Dacthal and diuron are more effective when applied to moist
soil; therefore, these herbicides should be applied immediately
following overhead irrigation or rain. Sufficient water should
be applied to wet the upper 3 or 4 inches of soil. Before any of
these herbicides are applied, the field should be freed of all weeds.
The chemicals are effective only against germinating seeds.
These herbicides may be applied with a knapsack sprayer or
with a power sprayer, using not less than 30 gallons of water per
acre of treated area; the sprayer pressure should not exceed
70 pounds per square inch. The spray equipment should be
thoroughly cleaned after use.

DRAINAGE AND IRRIGATION
Good aeration of soil and uniform moisture conditions pro-
mote maximum growth of gladiolus. With seep irrigation the
water table should be held at a uniform level as much as pos-
sible. For sandy soils, this level ranges from about 12 inches
for bulblets to 18 inches for flowering stock. Good soil drainage
is necessary to remove any excessive rainfall before roots are
damaged.
Overhead irrigation is applied as necessary to maintain a
moderate soil moisture. During prolonged dry periods over-
head irrigation is also, applied to seep-irrigated soils in order
to avoid troublesome accumulations of soluble salts in the soil
surface. Excessive salts kill roots when washed down by the
first rainfall.







Florida Agricultural Experiment Stations


The appearance of gladiolus leaves does not indicate when
to irrigate. Other kinds of plants which wilt readily may be
grown singly in several locations among the gladiolus to serve as
indicator plants; when the indicator plants wilt, irrigate the
gladiolus. Enough water should be applied at each sprinkling
to wet the soil thoroughly without causing puddling.
Overhead irrigation is applied before late afternoon so that
leaves will dry quickly. Prolonged periods of wetting provide
favorable conditions for disease spread. Pesticide sprays should
be applied after irrigating and only when plants are dry. To
be safe, irrigate the day before spraying.

SANITATION
The application of sanitary measures helps to avoid intro-
duction or spread of some important disease, weed, and nema-
tode pests. The cost of practicing sanitation is generally minor
compared to the benefits obtained. Two primary factors in sani-
tation are growing bulblets that were treated in hot water and
avoiding the introduction of untreated bulblets or planting stocks.
Also important is the destruction of diseased stocks and the im-
provement of good stocks by roguing. Stocks showing more
than 1 percent of virus-infected plants should not be used for
propagation if healthier stock is available. If the percentage
of infected plants is low, and if roguing is done both before and
during the flowering period, the stock can usually be cleaned
up in two or three years. Healthy "mother-block" stocks should
be isolated and maintained carefully.
All refuse from cleaning and sorting of bulbs should be de-
stroyed by burning or deep burial. Before re-using trays or
bags in which bulbs were stored, soak them for 10 minutes in a
solution of 4 pounds of Dowicide B per 100 gallons of water or
in a solution of 1 gallon of commercial formaldehyde in 20 gal-
lons of water. Cover with plastic or keep wet until the odor of
formaldehyde is gone.
Bulblets or bulbs to be planted in fumigated soil should not
be contaminated with soil or refuse. Machinery and tools must
be cleaned and sterilized by dipping or spraying with the form-
aldehyde solution mentioned above, so that untreated soil is
not carried to treated beds. Sieves and graders should be steril-
ized between bulb lots. If bulblets are soaked in water, treat
them promptly with Elcide 73, unless they are to be hot-water
treated.







Gladiolus Corm Production in Florida


FROST AND WIND DAMAGE
Overhead irrigation equipment should be set up and should
be in working condition for all plantings subject to frost. Irri-
gation should be started when the air temperature reaches 320
F. As the water freezes on leaves, much heat is released.
The ice itself does not protect leaves from freezing; there-
fore, sprinkling must be continued until the ice melts from
leaves. At the approach of frosty weather, avoid cultivating
the soil. Moisten the soil, preferably by overhead irrigation,
and also moisten a 100-foot strip of soil surrounding gladiolus
plantings. Warming of air by the earth's heat rays is more
effective when soil is moist to the surface. Running water down
the rows or in rim ditches during freezing weather is effective
in warming the surrounding air.
Wind-blown sand may cut off plants. Wind may also blow
the soil off the tops of beds, uncovering bulblets and bulbs. Thin
stands of bulblets are especially liable to wind-blown sand in-
jury. The sand may be held in place by keeping the soil surface
moist and by using herbicides to control weeds without cultiva-
tion. Windbreaks around bulblet plantings are recommended.

CONTROL OF WIREWORMS
One of the most important cultural practices is the treatment
of soil to control wireworms. Although wireworms are seldom
found feeding on the plants, the characteristic bulb scars (Fig.
14A) and holes in leaves and leaf distortion (Fig. 10) made by
wireworms are usually present unless adequate control measures
are applied. Wireworms cut off small leaves below ground and
cause scabby bulbs which may be difficult to sell. Wireworms
penetrate to the inner leaves in the "necks" of large plants caus-
ing injuries which initiate internal neck rot by bacteria and fungi
during warm, wet weather (Fig. 12B).
Chlordane and similar chlorinated insecticides have been used
successfully in the past, but are no longer very effective in some
areas. Parathion mixed into the soil before planting is recom-
mended for controlling wireworms. Di-Syston applied in the
furrow is most promising as a control measure in some areas.
Since control recommendations vary in the different bulb-grow-
ing areas, growers should obtain the latest information from the
county agricultural agent or from the nearest agricultural ex-
periment station.







Gladiolus Corm Production in Florida


FROST AND WIND DAMAGE
Overhead irrigation equipment should be set up and should
be in working condition for all plantings subject to frost. Irri-
gation should be started when the air temperature reaches 320
F. As the water freezes on leaves, much heat is released.
The ice itself does not protect leaves from freezing; there-
fore, sprinkling must be continued until the ice melts from
leaves. At the approach of frosty weather, avoid cultivating
the soil. Moisten the soil, preferably by overhead irrigation,
and also moisten a 100-foot strip of soil surrounding gladiolus
plantings. Warming of air by the earth's heat rays is more
effective when soil is moist to the surface. Running water down
the rows or in rim ditches during freezing weather is effective
in warming the surrounding air.
Wind-blown sand may cut off plants. Wind may also blow
the soil off the tops of beds, uncovering bulblets and bulbs. Thin
stands of bulblets are especially liable to wind-blown sand in-
jury. The sand may be held in place by keeping the soil surface
moist and by using herbicides to control weeds without cultiva-
tion. Windbreaks around bulblet plantings are recommended.

CONTROL OF WIREWORMS
One of the most important cultural practices is the treatment
of soil to control wireworms. Although wireworms are seldom
found feeding on the plants, the characteristic bulb scars (Fig.
14A) and holes in leaves and leaf distortion (Fig. 10) made by
wireworms are usually present unless adequate control measures
are applied. Wireworms cut off small leaves below ground and
cause scabby bulbs which may be difficult to sell. Wireworms
penetrate to the inner leaves in the "necks" of large plants caus-
ing injuries which initiate internal neck rot by bacteria and fungi
during warm, wet weather (Fig. 12B).
Chlordane and similar chlorinated insecticides have been used
successfully in the past, but are no longer very effective in some
areas. Parathion mixed into the soil before planting is recom-
mended for controlling wireworms. Di-Syston applied in the
furrow is most promising as a control measure in some areas.
Since control recommendations vary in the different bulb-grow-
ing areas, growers should obtain the latest information from the
county agricultural agent or from the nearest agricultural ex-
periment station.









r1


Fig. 10.-Effect of early wireworm damage on leaves from large bulbs.

DISEASES AND OTHER DISORDERS
Gladiolus plants grown from bulblets and planting stock are
more often injured by diseases and insects than the larger plants
grown for flowers. The Curvularia disease made the growing
of bulblets a hazardous business in Florida until the hot-water
treatment of bulblets was generally practiced. The best and
least expensive control programs depend for their success on
early and correct diagnosis of the trouble and prompt applica-
tion of the recommended spray schedule. Check lists of plant
and bulb symptoms have been designed to help in the diagnosis
of most disorders of gladiolus (Tables 4 and 5).







Gladiolus Corm Production in Florida


Special precautions in gladiolus culture are necessary because
the plants react differently than most crops to certain chemicals.
1. The use of any of the following compounds on gladiolus
should be avoided, because they usually burn the leaves
severely: (a) copper fungicides as spray or dust, (b)
calcium cyanamide, (c) all fluorine compounds including
cryolite and fluoride baits.
2. Superphosphate fertilizer should not be spread where the
dust may drift on to wet gladiolus leaves.
3. Recommendations developed for gladiolus culture on sand
lands should be used with caution in other soil types and
areas of Florida. Concentrations of chemicals that are
safe and effective in light sandy soils may be injurious
or ineffective in heavier soils.

SPRAYING
The Curvularia fungus, living over in the soil and carried on
bulblets and bulbs, damages small plants severely by rotting the
roots and leaves and attacking the new bulbs. Curvularia is
the main disease problem in hot and warm weather. Curvularia
neck rot that kills the older leaves one at a time on small plants
may occur when few spot infections are seen on leaves (Fig. 11).
The fungus spreads below ground as well as in the air. Regular
spraying, started before the disease appears, is fairly effective
in preventing leaf spot infections, but after the infections have
spread to many leaves, the disease is difficult to control.
During winter months spray once each week but, beginning
about April 1, spray twice weekly with maneb, 11/2 pounds per
100 gallons. When plants are wet or when the spray may not
dry off promptly, substitute 2 pounds zineb for the maneb. These
fungicides are wettable powders sold under various trade names,
including Dithane, Manzate, and Parzate. After leaf spots ap-
pear, three or four sprayings per week may be necessary during
wet weather.
A warm weather disease, bacterial leaf spot, may be found
in one or two small areas of the field (Fig. 12F). Streptomycin
(a formulation without copper) is recommended at 200 ppm as
a weekly spray. Fungicides are ineffective.
Stemphylium leaf spot may develop in cool weather on older
plants of certain varieties (Fig. 12E). To control this leaf spot,
Dyrene is used at 112 pounds per 100 gallons as a spray once each






Florida Agricultural Experiment Stations


week. A separate application of maneb should also be made
once each week, or twice a week if Curvularia infections should
be controlled.
Cutworms are difficult to control on plantings made in warm
weather unless chlordane is applied to the soil around the plants
as the sprouts emerge. Usually two or three sprays or a soil
application of granular chlordane (10 percent) are needed to
control these large worms. Dusts are not recommended because
they may injure young leaves.
"Worms" which chew leaves and stalks are usually controlled
by spraying once each week with 3 pounds DDT 50 WP plus 2
pounds parathion 15 WP per 100 gallons. These insecticidal pow-
ders are added to the fungicidal spray. In rainy weather 4
ounces of a spreader-sticker may be added to each 100 gallons.
A grower who has little experience in using parathion, or whose
sprayer operator is careless, should use 6 pounds chlordane
40 WP per 100 gallons in place of DDT plus parathion. In hot,
dry weather spider mites should be controlled, either by using
the parathion spray or by dusting with sulfur. Kelthane is
also used.
All the precautions and safety measures given on the manu-
facturers' labels for all compounds should be followed carefully
to avoid the hazard of poisoning or gradual sensitization to chem-
icals.
Note: Before using a sprayer for gladiolus, rinse out resi-
due of any chemicals used on other crops.

Fig. 11.-Bulblet plants killed by Curvularia disease.


4
i

II d ,: ,-k~;?~

i


A. K :{-. tL*


- -


































II








P 4




Fig. 12.-Disease symptoms on gladiolus leaves.
A. Yellow bands in young leaves, a temporary effect of bright sun on new
growth.
B. Neck rot associated with wireworm injuries in warm, wet weather.
Young leaves rot as they grow through neck regions where wireworms
feed. Note feeding holes near base.
C. Curvularia spots on leaf. New small spots are typically rectangular with
the greater dimension perpendicular to leaf veins.
D. Botrytis spots on leaves may be small to very large. The small dark
brown spots usually show only on upper side of leaf. Gray mold on
large spots helps to identify Botrytis.
E. Stemphylium spots may be identified by the small, round, yellowish
translucent spots with reddish brown centers. Large, light brown
spots may also be present.
F. Bacterial leaf spot, showing the dried bacterial ooze that glistens like
varnish.








TABLE 4.-CHECK LIST OF SYMPTOMS ON GROWING PLANTS.


Abnormal Appearance of Plants Cause of Trouble Comments


1. Yellow bands across young leaves, often
marking daily growth (Fig. 12A).



2. Isolated holes in leaves plus underground
damage and leaves cut off at soil sur-
face. Dark brown rot or yellow-brown
spotting of inner leaves of large plants
(Fig. 12B). Late-season neck rot.
3. Diseased leaf spots:
A. Brown oval spots on younger leaves;
spots enlarge, especially along edge
of leaf (Fig. 12C).
B. Numerous round brown spots of all
sizes, mostly small; the smallest are
visible only on top side of leaf (Fig.
12D).
C. Brown, medium-size spots scattered
with black, pimple-like spore bodies.


Bright sun after
cool night with
good growing
conditions.
Wireworms.






Curvularia
fungus.

Botrytis fungus.




Septoria fungus.


Yellow areas usually turn green after
several days, but occasionally leaf is
"pinched" in at yellow band and does
not recover.
Vertical row of holes is caused by daily
(or successive) feedings on emerging
leaf. The very small wireworms cause
neck rot of mature plants in warm, wet
weather.

This is a hot weather disease. Note the
groups of spores similar to coarse black
pepper near center of spots.
Note gray mold (spores) on dead flow-
ers, on rotted necks, and on the large
leaf spots (easily seen when wet with
dew). Cool weather disease.
Not found in central or south Florida;
occasionally seen in north Florida.




D. Small, reddish brown spots surround-
ed by ring of clear (translucent) yel-
lowish tissue; usually numerous.
Also large, oval, light brown spots
found on some varieties (Fig. 12E).
E. Watersoaked streaks between veins
(Fig. 12F). Older lesions are brown.


4. Yellow older leaves; bulbs or bulblets
with soft brown rot. (Top is easily
pulled off of bulb.) (Fig. 13A).

5. Short spikes from large plants, occasion-
al neck rot, and roots mostly rotted.
Sclerotia seen in dead roots and neck.
(Fig. 13B).
6. Neck rot spreading along row of bulblet
plants, not spreading much in large
plants. Very small, black, pimple-like
sclerotia found in dead tissue (Fig.
13C).
7. Light green mosaic or yellowish flecking
on leaves; flower petals blotched or
flecked with lighter or darker colors;
short plants (Fig. 13D).


Stemphylium
leaf spot fungus.



Bacteria.



Fusarium fungus
carried in bulbs
or bulblets.

Stromatinia
(Sclerotinia)
dry rot fungus.

Stromatinia
(Sclerotinia)
dry rot fungus.


Virus diseases.


Attacks older leaves of a few varieties.
This is a cool to warm weather disease.



Rarely found in north or central Flor-
ida; not yet found in south Florida.
Limited to small plants bulbletss or
planting stock).
Usually found scattered uniformly
through plantings, or more severely in
wet areas. Does not usually seem to
spread from bulb to bulb.
Infection comes from fungus residue in
soil. Occurs on "old" gladiolus soil in
cool weather. Symptoms more severe
in wetter parts of planting.
In "clean" soil (soil in which gladiolus
not previously grown) infection comes
from bulbs; in "old" gladiolus soil, in-
fection usually comes from soil.

Stocks with much virus disease infec-
tion should be discarded, or carefully
rogued for at least two years, especially
at blooming time.








CHECK LIST OF SYMPTOMS (continued)


Abnormal Appearance of Plants Cause of Trouble Comments


8. Leaf tip burn and scorch.











9. Silvery scars on leaves and flower buds;
inactive, small butter-yellow thrips un-
der leaf folds (Fig. 13E).
10. Small brown spots on side of leaf where
spray and dew collect, and where leaf
faces sun more directly.


Many causes, in-
cluding: low soil
pH, drying wind
+ dry soil or
poor roots, ferti-
lizer salts concen-
trated in dry soil,
superphosphate
fertilizer clinging
to wet leaves, and
fluorine scorch.
Gladiolus thrips.



Undetermined.


Data indicate a minor "tip burn" is cor-
related with soil pH: little at pH 6.0 or
higher, and progressively more severe
below pH 5.8, but seldom deeper than
1 inch from tip. When burn or scorch
appears below tip 1/2 inch in many va-
rieties, other factors such as poor roots
or fluorine contamination may be re-
sponsible.



Seen in cool weather, seldom after May
in south Florida.

Does not spread.











































." I -




Fig. 13.-Pest damage on gladiolus plants.
A. Fusarium infection of bulbs, causing small, curved plants and yellow
outer leaves. Healthy plants on left.
B. Early and late stages of Stromntinia neck rot.
C. Stromatinia (Sclerotinia dry rot) infection killing planting stock.
D. Cucumber mosiac virus infection.
E. Flowers scarred and deformed by thrips.








TABLE 5.-CHECK LIST OF SYMPTOMS ON HARVESTED BULBS.


Abnormal Appearance of Bulbs Cause of Trouble Comments


1. Discolored areas, especially around the
base and where bulb is not protected
by husk. Underlying tissue is often
chalky.

2. Small round scabs that, when lifted,
leave a smooth, bowl-shaped depression
(Fig. 14A).

3. Light brown tissue progressing from
rubbery to leathery texture. Sometimes
covered with black mold.


4. Jelly-like rot at base of small bulbs, later
becoming chalky (Fig. 14B).
5. Cores either rotted out or depressed
("doughnut bulbs").


Bruises and cuts.





Bacterial scab:
usually results
where wireworms
injured bulbs.
Sunburn of bulbs.




Rootknot nema-
todes.
Fusarium, Peni-
cillium and prob-
ably other fungi
and bacteria.


Bruises do not significantly reduce value
of bulbs unless followed by fungus in-
fection and rotting. However, bruising
of small bulbs may result in extreme
drying and death.
Value of bulbs for flower production not
materially reduced by scab infection.


Usually seen on bulbs exposed to sum-
mer sun; but may occur just before dig-
ging when bed top is cleaned off, leav-
ing 1 to 2 inches of dry hot soil to cover
bulbs.
Jelly-like condition disappears rapidly
after harvest.
Commonly seen when bulbs are dug
from wet soil in summer, especially
where harvesting was delayed.





6. Dark-stained husks, sometimes shredded
at top; small black spots or shallow rot-
ted areas grouped along the lines of husk
attachment on top and shoulders of bulb
(Fig. 14C).
7. A soft watery rot which changes into a
spongy rot. Found in core, in vascular
tissues or in whole bulb; eventually caus-
ing lightweight, unshriveled bulb (Fig.
14D).
8. Small to medium-size, dark brown rot
spots, mostly shallow, but often invad-
ing vascular tissue (Fig. 14E).
9. Dull or dark husks.





10. Stringy, white mold that kills plants and
bulblets before harvest (Fig. 14F).

11. Firm, tough rot extending into bulb,
often along vascular tissue. Mostly
found around base or core of bulb, re-
ducing entire bulb to stone-like "mum-
my" while in storage (Fig. 14G).


Stromatinia dry
rot.



Botrytis soft rot.





Curvularia infec-
tion.

Delay in digging
mature bulbs
from moist soil;
also bulb dis-
eases.
Southern blight
(Sclerotium
rolfsii).
Fusarium brown
rot.


Bulbs usually smaller than others in
same lot because tops died early from
neck rot.


Appears only after bulbs have been in
cool storage (below 55F) for a few
weeks or more.


Spots may be small or indistinct at har-
vest time.

Often an indication of diseased or poor
bulbs.



Occasionally found in dry, hot weather.
The brown sclerotia resemble radish
seed.
There are several kinds of Fusarium
infections and symptoms. The most
troublesome kind is not visible but lies
dormant near core and causes poor flow-
er production or later bulb rot.








TABLE 5.-CHECK LIST OF SYMPTOMS ON HARVESTED BULBS (continued)

Abnormal Appearance of Bulbs Cause of Trouble Comments


12. Greenish rot sometimes extending into
core or vascular tissues.


13. Bulbs partly or completely soft and wa-
tery.
14. Moldy bulbs in storage, usually a green
mold.






15. Light-colored, spongy or chalky pits,
shallow or deep in bulb.


Penicillium fun-
gus.

Freezing injury.


Common molds
that grow at
higher humidi-
ties in cold stor-
age and where air
movement is re-
duced.
Physiological
breakdown that
may be caused by
bruising and
close confinement
of bulbs during
shipping and
storage.


Seen only in bulbs harvested in cool,
moist weather and cured under poor
drying conditions.
Found on outer bulbs of packages
shipped in freezing weather.
Soft root sprouts are killed by the
molds.






May occur spontaneously in very large
bulbs; similar to bitter pit in apple.








Gladiolus Corm Production in Florida


SJ~~


Fig. 14.-Disease symptoms on gladiolus bulbs.
A. Bacterial scab initiated by wireworm injuries. Note dark husks of in-
jured bulbs.
B. Galls on roots caused by rootknot nematode infection. Such roots may
be associated with jelly-rot of small bulbs.
C. Stromatinia dry rot. Husks (below) are typically stained by fungus
growth.
D. Botrytis infection of bulbs, showing internal browning (below) and
white mold.
Fig. vula4.-Disease symptoms on gladolus bulbs.
A. Bacterial scab initiated by wireworm injuries. Note dark husks of in-
jured bulbs.
B. Galls on roots caused by rootknot nematode infection. Such roots may
be associated with jelly-rot of small bulbs.
C. Stromatinia dry rot. Husks (below) are typically stained by fungus
growth.
D. Botrytis infection of bulbs, showing internal browning (below) and
white mold.
E. Curvularia infection of small bulbs.
F. Sclerotium rolfsii (southern blight) fungus has killed the bulblets.
G. Fusarium rot. Internal infection shown on sectioned bulb (right).


25:







Florida Agricultural Experiment Stations


HARVESTING
Bulbs are usually dug before the leaves turn yellow, since
they are more susceptible to disease infections when left in the
soil after the roots or tops die. Maximum bulb size is generally
attained in six to seven months from bulblets planted in winter.
A shorter growing season (five to six months) is sufficient for
late spring plantings. Bulbs maturing in cool weather "size
up" rapidly as compared to warm-weather bulbs. Bulbs from
planting stock as well as from bulblets are usually ready to har-
vest three weeks after the larger bulblets darken but while the
smaller bulblets are still white. Do not irrigate during the last
few weeks.
For best utilization of labor and equipment, harvesting may
be started early, before maximum bulb size is made, or about
51/ months after a winter planting of bulblets. Although bulb
size is increased if harvest is delayed another month, more of
the bulblets would be lost by shattering unless special digging
equipment is used. Vibrating sieves or screens that separate
bulbs from bulblets and allow the soil to pass through are valu-
able in saving bulblets as well as labor (Fig. 15).



:--2-
















Fig. 15.-Harvesting of small bulbs and bulblets. The digger under
tractor lifts soil with bulbs onto shaker sieves made of stainless steel sheets.
Bulbs come off top sheet and bulblets off second sheet. Dry sand falls
through both. Top sheet has 1/2 x 3/4 inch holes and second sheet has
3/16 x 3/4 inch holes stamped out.







Gladiolus Corm Production in Florida


Modified potato diggers or specially-designed bulb diggers are
used to harvest large bulbs unless the bulblets are to be saved,
in which case hand-labor or the sieves are used. Turning the
bulbs out with a small plow or half sweep and picking them up
by hand reduces bruising and decreases the loss of bulblets.
Many flower growers reduce the cost of handling bulbs by clean-
ing them immediately after digging. (See section on Curing
and Grading Bulbs.)
The summer sun scorches bulbs quickly; therefore, plow up
no more bulbs than can be picked up in 10 minutes and placed in
the shade. Harvesting, grading, and cleaning operations cause
small bruises and punctures that may result in rotting even
though the injuries may be unnoticed. Slowly cured bulbs are
most susceptible to infections. Captan, as a dust or dip applied
within a day after harvesting, controls these infections and pro-
tects the bulbs later when they are bruised in the cleaning and
grading operations. Follow the recommendations given in Ta-
ble 1.

CURING AND GRADING BULBS
Curing is the drying of bulbs after harvest. Prompt curing
reduces disease losses. Optimum conditions for drying bulbs
are temperatures of 80 to 90 F and a relative humidity between
40 and 50 percent. Bulbs can be killed or injured by drying too
rapidly, especially after the second day of curing. The heating
of air may be unnecessary (except at night) in modern forced-air
driers. Bulbs cannot be cured well in bulk unless air is forced
through them. When cured in stacked trays with air circulated
by a fan, bulb layers should be only three bulbs deep.
Quick curing allows cleaning of the bulbs about one week
after digging unless they were cleaned at harvest time. "Clean-
ing" involves removal of the roots and the "mother" bulb. Large
bulbs are cleaned by hand, but only the roots and bulblets need
to be removed from bulblet-grown bulbs. When very dry, the
roots may be broken off by running the bulbs over screens or
over a shaker sieve used in harvesting. If not previously treated,
dip or dust bulbs with captain plus Thylate after the roots or old
bulbs are removed (see Table 1).
Immediately after bulbs are cleaned they are run through
grading machines (Fig. 16) or sieves and separated into the fol-
lowing sizes:








Florida Agricultural Experiment Stations


'p


J


'V


Fig. 16.-"Grader" for sorting bulbs into various sizes.


i~t ~i

I

1:;r


~h-
.~
.1. .,
r
Ir
~







Gladiolus Corm Production in Florida


Jumbo size bulbs-over 2 inches in diameter.
No. 1 bulbs-l1/ to 2 inches in diameter.
No. 2 bulbs-11/4 to 11/2 inches in diameter.
No. 3 bulbs-1 to 11/ inches in diameter.
No. 4 bulbs--/, to 1 inch in diameter.
No. 5 bulbs--/2 to /4 inch in diameter.
No. 6 bulbs-3/8 to 1/ inch in diameter.
Planting stocks are No. 4, 5, and 6 bulbs grown from bulblets;
flowering stocks are No. 3 bulbs and larger. Bulbs to be sold are
counted either by hand or by mechanical or electronic counters
with an endless-belt conveyor. The number of small bulbs is
approximated by applying the average weight per thousand bulbs
to the total weight.
In handling bulbs and bulblets much care must be taken to
avoid mixing of varieties or mixing of different stocks of the
same variety. Carelessness or lack of supervision at each step
of planting, harvesting, curing, and storing often results in
variety mixing. One variety or stock should be handled at a
time. Bulb trays and bags should be tight enough to prevent
escape of the smallest bulblets into another package. Labels
which are placed inside and outside of each package, as well as
field stakes, should be marked with weather-proof pencils or
special water-proof ink markers.

BULB YIELDS
About 30 bulbs larger than 1/2 inch in diameter can be dug per
foot of row in a well-managed bulblet planting (Fig. 17). With
some varieties planted in single rows on 3-foot centers, about
500,000 bulbs are harvested per acre; with double rows, about
1 million bulbs; and from closely planted seedbeds, about 2
million bulbs. The size of bulbs produced depends mainly on
variety, season, and growing conditions. The number of flower-
ing-size bulbs produced per acre from bulb sizes No. 5 and 6 is
about 175,000 for single rows to 350,000 for double-row beds
with 3-foot centers.

PREPARATION OF BULBS FOR STORAGE
Cold treatment of large bulbs serves either of two purposes:
(1) to break dormancy of hot-weather bulbs or (2) to delay
sprouting of cold-weather bulbs that often have very little or
no dormancy after a few weeks of curing. Dormancy is broken







Gladiolus Corm Production in Florida


Jumbo size bulbs-over 2 inches in diameter.
No. 1 bulbs-l1/ to 2 inches in diameter.
No. 2 bulbs-11/4 to 11/2 inches in diameter.
No. 3 bulbs-1 to 11/ inches in diameter.
No. 4 bulbs--/, to 1 inch in diameter.
No. 5 bulbs--/2 to /4 inch in diameter.
No. 6 bulbs-3/8 to 1/ inch in diameter.
Planting stocks are No. 4, 5, and 6 bulbs grown from bulblets;
flowering stocks are No. 3 bulbs and larger. Bulbs to be sold are
counted either by hand or by mechanical or electronic counters
with an endless-belt conveyor. The number of small bulbs is
approximated by applying the average weight per thousand bulbs
to the total weight.
In handling bulbs and bulblets much care must be taken to
avoid mixing of varieties or mixing of different stocks of the
same variety. Carelessness or lack of supervision at each step
of planting, harvesting, curing, and storing often results in
variety mixing. One variety or stock should be handled at a
time. Bulb trays and bags should be tight enough to prevent
escape of the smallest bulblets into another package. Labels
which are placed inside and outside of each package, as well as
field stakes, should be marked with weather-proof pencils or
special water-proof ink markers.

BULB YIELDS
About 30 bulbs larger than 1/2 inch in diameter can be dug per
foot of row in a well-managed bulblet planting (Fig. 17). With
some varieties planted in single rows on 3-foot centers, about
500,000 bulbs are harvested per acre; with double rows, about
1 million bulbs; and from closely planted seedbeds, about 2
million bulbs. The size of bulbs produced depends mainly on
variety, season, and growing conditions. The number of flower-
ing-size bulbs produced per acre from bulb sizes No. 5 and 6 is
about 175,000 for single rows to 350,000 for double-row beds
with 3-foot centers.

PREPARATION OF BULBS FOR STORAGE
Cold treatment of large bulbs serves either of two purposes:
(1) to break dormancy of hot-weather bulbs or (2) to delay
sprouting of cold-weather bulbs that often have very little or
no dormancy after a few weeks of curing. Dormancy is broken







Florida Agricultural Experiment Stations


Fig. 17.-Production of bulbs from 1 foot of a row planted to bulblets.

by one to three months' storage at temperatures between 36
and 45' F. The longer period is usually needed for smaller bulbs
and bulblets. To improve uniformity of sprouting after plant-
ing and to shorten the blooming period all bulbs need at least
two weeks of cold treatment, even though some of them are
ready to sprout.
To avoid premature sprouting in prolonged storage of cool-
weather bulbs, hold at a temperature of about 40 F or some-
what lower and a relative humidity of 65 to 75 percent and cir-
culate the air uniformly. With warm-weather bulbs, storage
temperature may be from 36 to 450 and relative humidity from
75 to 85 percent, provided air circulation is adequate and storage
period is under four months. For longer periods hold tempera-
ture at 40 or lower and humidity at 65 to 75 percent. To keep
bulbs from freezing in cold climates, warehouses should be heated
when necessary.
Circulation of air to all parts of the storage room and through
all containers of bulbs or bulblets is very important. Insufficient
air movement causes localized build-up of humidity, resulting in
bulb rot, mold, and sprouting. Stacks of bulb trays should be
separated by at least 2 inches from walls, floor, and other stacks.
Ventilation or occasional renewal of air is also important to pre-
vent accumulation of respiration by-products of the bulbs, espe-







Gladiolus Corm Production in Florida 47

cially of bulbs that are rotting or sprouting. These gaseous by-
products are poisonous to bulbs, predisposing them to rotting
and physiological breakdowns such as chalky pit. Storage room
doors should be opened for an hour or two once or twice per
week, especially during the first two weeks and the last two
weeks of storage period. Severe crop losses have occurred due
to effects of toxic gases produced by sprouting bulbs in a closed
room when refrigeration failed for several days.







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