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Group Title: Bulletin - University of Florida. Agricultural Experiment Station ; no. 291
Title: Relative susceptibility of some annual ornamentals to root-knot
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027128/00001
 Material Information
Title: Relative susceptibility of some annual ornamentals to root-knot
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 15 p. : ill., chart ; 23 cm.
Language: English
Creator: Goff, C. C
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1936
 Subjects
Subject: Annuals (Plants) -- Diseases and pests -- Florida   ( lcsh )
Flowers -- Diseases and pests -- Florida   ( lcsh )
Root-knot   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: by C.C Goff.
General Note: Cover title.
Funding: Bulletin (University of Florida. Agricultural Experiment Station) ;
 Record Information
Bibliographic ID: UF00027128
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000924369
oclc - 18210187
notis - AEN4987

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    Credits
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Full Text

February, 1936


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA
WILMON NEWELL, Director










RELATIVE SUSCEPTIBILITY

OF SOME ANNUAL ORNAMENTALS

TO ROOT-KNOT





By C. C. GOFF












Bulletins will be sent free to Florida residents upon application to
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA


Bulletin 291







EXECUTIVE STAFF

John J. Tigert, M.A., LL.D., President of the
University
Wilmon Newell, D.Sc., Director
H. Harold Hume, M.S., Asst. Dir., Research
Harold Mowry, M.S.A., Asst. Dir., Adm.
J. Francis Cooper, M.S.A., Editor
Jefferson Thomas, Assistant Editor
Clyde Beale, A.B.J., Assistant Editor
Ida Keeling Cresap, Librarian
Ruby Newhall, Administrative Manager
K. H. Graham, Business Manager
Rachel McQuarrie, Accountant

MAIN STATION, GAINESVILLE

AGRONOMY
W. E. Stokes, M.S., Agronomist**
W. A. Leukel, Ph.D., Agronomist
G. E. Ritchey, M.S.A., Associate*
Fred H. Hull, Ph.D., Associate
W. A. Carver, Ph.D., Associate
John P. Camp, M.S., Assistant
ANIMAL HUSBANDRY
A. L. Shealy, D.V.M., Animal Husbandman**
R. B. Becker, Ph.D., Dairy Husbandman
W. M. Neal, Ph.D., Asso. in An. Nutrition
D. A. Sanders, D.V.M., Veterinarian
M. W. Emmel, D.V.M., Asst. Veterinarian
N. R. Mehrhof, M.Agr., Poultry Husbandman
W. W. Henley, B.S.A., Asst. An. Husbandman
Bradford Knapp, Jr., M.S., Asst. An. Hush.
P. T. Dix Arnold, B.S.A., Assistant Dairy
Husbandman
L. L. Rusoff, M.S, Laboratory Assistant
Jeanette Shaw, M.S., Laboratory Technician
CHEMISTRY AND SOILS
R. W. Ruprecht, Ph.D., Chemist"
R. M. Barnette, Ph.D., Chemist
C. E. Bell, Ph.D., Associate
R. B. French, Ph.D., Associate
H. W. Winsor, B.S.A., Assistant
ECONOMICS, AGRICULTURAL
C. V. Noble, Ph.D., Agricultural Economist"
Bruce McKinley, A.B., B.S.A., Associate
Zach Savage, M.S.A., Associate
A. H. Spurlock, M.S.A., Assistant
ECONOMICS, HOME
Ouida Davis Abbott, Ph.D., Specialist"
C. F. Ahmann, Ph.D., Physiologist
ENTOMOLOGY
J. R. Watson, A.M., Entomologist"
A. N. Tissot, Ph.D., Associate
H. E. Bratley, M.S.A., Assistant
HORTICULTURE
A. F. Camp, Ph.D., Horticulturist"
G. H. Blackmon, M.S.A., Horticulturist and
Associate Head of Department
A. L. Stahl, Ph.D., Associate
F. S. Jamison, Ph.D., Truck Horticulturist
R. J. Wilmot, M.S.A., Specialist, Fumigation
Research
R. D. Dickey, B.S.A., Assistant Horticulturist
PLANT PATHOLOGY
W. B. Tisdale, Ph.D., Plant Pathologist"
George F. Weber, Ph.D., Plant Pathologist
R. K. Voorhees, M.S., Assistant***
Erdman West, M.S., Mycologist
Lillian E. Arnold, M.S., Assistant Botanist
Stacy O. Hawkins, M.A., Assistant Plant
Pathologist
SPECTROGRAPHIC LABORATORY
L. W. Gaddum. Ph.D., Biochemist
L. H. Rogers, M.A., Spectroscopic Analyst


BOARD OF CONTROL
Geo. H. Baldwin, Chairman, Jacksonville
A. H. Wagg, West Palm Beach
Oliver J. Semmes, Pensacola
Harry C. Duncan, Tavares
Thomas W. Bryant, Lakeland
J. T. Diamond, Secretary, Tallahassee

BRANCH STATIONS
NORTH FLORIDA STATION, QUINCY
L. O. Gratz, Ph.D., Plant Pathologist in
Charge
R. R. Kincaid, Ph.D., Asso. Plant Pathologist
J. D. Warner, M.S., Agronomist
Jesse Reeves, Farm Superintendent
CITRUS STATION, LAKE ALFRED
A. F. Camp, Ph.D., Horticulturist in Charge
John H. Jefferies, Superintendent
W. A. Kuntz, A.M., Assoc. Plant Pathologist
B. R. Fudge, Ph.D., Associate Chemist
W. L. Thompson, B.S., Asst. Entomologist
EVERGLADES STATION, BELLE GLADE
A. Daane, Ph.D., Agronomist in Charge
R. N. Lobdell, M.S., Entomologist
F. D. Stevens, B.S.. Sugarcane Agronomist
Thomas Bregger, Ph.D., Sugarcane Physiologist
G. R. Townsend, Ph.D., Assistant Plant
Pathologist
J. R. Neller, Ph.D., Biochemist
R. W. Kidder, B.S., Assistant Animal
Husbandman
Ross E. Robertson, B.S., Assistant Chemist
B. S. Clayton, B.S.C.E., Drainage Engineer
SUB-TROPICAL STATION, HOMESTEAD
H. S. Wolfe, Ph.D., Horticulturist in Charge
W. M. Fifield, M.S., Asst. Horticulturist
Geo. D. Ruehle, Ph.D., Associate Plant
Pathologist
W. CENTRAL FLA. STA., BROOKSVILLE
W. F. Ward, M.S.A., Asst. An. Husbandman
in Charge*

FIELD STATIONS
Leesburg
M. N. Walker, Ph.D., Plant Pathologist in
Charge
W. B. Shippy, Ph.D,. Asso. Plant Pathologist
K. W. Loucks, M.S., Asst. Plant Pathologist
J. W. Wilson, Ph.D., Associate Entomologist
Plant City
A. N. Brooks, Ph.D., Plant Pathologist
Cocoa
A. S. Rhoads, Ph.D., Plant Pathologist
Hastings
A. H. Eddins, Ph.D., Plant Pathologist
Monticello
G. B. Fairchild, M.S., Asst. Entomologist***
Bradenton
Davi.l G. Kelbert, Asst. Plant Pathologist
C. C. Goff, M.S., Assistant Entomologist
Sanford
E. R. Purvis, Ph.D., Assistant Chemist.
Celery Investigations
Lakeland
E. S. Ellison, Ph.D., Meteorologist*
B. H. Moore, A.B., Asst. Meteorologist*
W. 0. Johnson, B.A., Asst. Meteorologist*
R. T. Sherouse, Asst. Meteorologist*
M. L. Blanc. Asst. Meteorologist*

*In cooperation with U.S.D.A.
** Head of Department.
*** On leave.









RELATIVE SUSCEPTIBILITY
OF SOME ANNUAL ORNAMENTALS
TO ROOT-KNOT

By C. C. GOFF

Root-knot is a very important factor in the growing of annual
ornamentals, for both the commercial grower and for the person
who grows a few flowers for the home. Generally the ground
for the annual garden is a small plot used year after year, and
it is in this type of plot that the root-knot nematodes become
most abundant. In a small area of this sort it is comparatively
easy to treat the soil and reduce the infestation. The grower,
however, may not be able to afford the cost of the materials
for controlling the infestation, or may not care to go to the
trouble of treating. In that case it is of interest to know what
flowers can be grown on the land and be free of root-knot or
little affected by it. Since little was known about the relative
susceptibility to the root-knot nematode of the various annual
ornamentals commonly grown in Florida, experiments were car-
ried out to determine this.

EXPERIMENTAL PLANTINGS

Four plantings were made near Leesburg on Blanton fine sand.
Two of these were made in the late fall and winter of 1932-33
and 1933-34, and two in the spring of 1933 and 1934. Most of
the plants used were started in flats from which the young
plants were set in the field. In the cases where the plants were
not of the type that could be transplanted easily, the seed was
planted directly in the experimental plot.
For the most part the plants tested were annuals and perenni-
als commonly grown as annuals in Florida gardens.
Planting No. 1.-The plants and seeds were placed in the field
from November 4, 1932, to January 9, 1933, and the plants taken
up from March 16, 1933, to March 21, 1933. The great variation
in time of planting of the different plants might be expected
to cause considerable variation in the infestation. However,
from the results, it seems to have had very little effect.






Florida Agricultural Experiment Station


The planting was made on heavily infested soil, and, to make
doubly sure that the plants were exposed to the attack of the
nematode, infested roots of whip-poor-will cowpeas and tomatoes
were placed in the rows at time of planting. Triplicate plots
were used, 11 plants being set out in each plot. In a few cases
where seed was planted in the field more than 33 plants were
raised. In some cases the mortality was high due to unfavorable
field conditions. This plot was on h gh, sandy ground, contain-
ing very little humus and with no protection from the sun.
During dry periods the plants were irrigated by shallow ditches
between the rows, the water being pumped to the higher side
of the plot and turned into the ditches.
Planting No. 2.-This planting was made from March 28 to
April 10, 1933, and the plants were taken up on July 19 and 20.
Because of a change in the irrigation system, it was necessary
to change the location of the plot. Again infested ground was
selected and infested roots from the first planting were cut up
and worked into the soil. Nevertheless, the infestation of root-
knot in this planting was lighter than in the preceding one.
Due to damage in the irrigation system which could not be
immediately repaired, a number of plants were lost during dry
weather. In this planting duplicate plots were used, starting
with 26 plants of each variety tested in each plot.
The plot on which these plants were grown was of the same
soil type as that used in the first planting. When the plants
were taken up the plot was plowed and sowed to whip-poor-will
cowpeas to maintain the infestation of root-knot for the next
planting.
Planting No. 3.-This planting was made on December 1,
1933, and January 1, 1934, and the plants were taken up from
April 19 to April 26, 1934. Five plots were used with five plants
of each variety in each plot. The infestation seemed to be uni-
form throughout.
Planting No. 4.-This planting was made from March 5 to
March 27, 1934, and the plants were taken up from June 2 to
June 6, 1934.
With this planting which was practically the same as No. 3,
the most satisfactory method of laying out the plot was found.
Five plots were used with seven plants in each. Each row was






Relative Susceptibility of Ornamentals to Root-Knot 5

521/9 feet long and divided into seven parts, each 71/2 feet long.
Seven plants were placed in each part. The rows were 18 inches
apart and as there were 49 kinds of plants each plot consisted
of seven rows. Thus, the whole area covered by the five plots
lying side by side was a 521/2 foot square. This eliminated the
chance of the wide variation of infestation that might occur
in large areas and made the plots easier to irrigate.

TABLE 1.-TOTAL NUMBER OF EACH KIND OF PLANT, DEGREE OF INFESTA-
TION BY ROOT-KNOT, AND NUMBER AND PERCENTAGE OF PLANTS IN EACH
GROUP FOR PLANTING NO. 1, WINTER OF 1932.


Plants


-3
E- Z


Blue laceflower............. 32
Calendula........................ 29
Gypsophila ...................... 22
Helichrysum ................ 33
Pansy ............................. 21
Cynoglossum ............. 28
Ann. sweet pea.............. 27
Lobelia ...................- 31
Snapdragon .................... 32
Centaurea...............--...--.. 33
Radio calendula............ 14
Salpiglossis ................... 15
Hollyhock........................ 20
Matricaria................ 15
Nasturtium .................... 45
Aquilegia ....................... 20
Linaria ... .......... 32
California poppy............ 32
Sunflower........................ 56
Acroclinium .................. 19
Verbena .......................... 31
Marg. carnation............ 30
Physalis ............... ..... 18
Petunia-----.--.-------30
Godetia............................ 22
Godetia ............................ 22
Shasta daisy....... ...... 13
China aster-.................... 21
Phlox...........................-..-- 33
Candytuft...................... 30
Pinks .............................. 33
Stock ....................---......--...... 33
Zinnia--- ........................... 27
Gerbera daisy................ 9
Arctotis..........................- 32
Calliopsis....................... 33
Sweet alyssum---................ 25
Cosmos ............. -- ............. 26
Coreopsis ........................ 32
Michaelmas daisy.......... 33
African marigold .......... 65


Number of Plants and Percentages Infested
Very Heavily Mod. Lightly Very Not
Heavily Infested Infested Infested Lightly Infested
Infested Infested
No. %INo. % No. % No. % No. _% No. %

32 100
29 100
21 95 1 5
30 91 3 9
19 90 2 10
25 89 3 11
23 85 4 15
22 71 9 29
25 78 3 9 4 13
16 49 15 45 2 6
9 65 2 14 2 14 1 7
4 26 10 67 1 7
7 35 10 50 2 10 1 5
15 100
2 4 31 69 12 27
1 5 13 65 5 25 1 5
6 19 13 40 7 22 5 16 1 3
7 22 11 34 8 25 4 13 2 6
35 62 12 22 9 16
1 5 7 37 5 26 6 32
14 45 8 26 9 29
14 45 3 10 9 30 3 10 1 3
3 17 1 5 7 39 7 39
1 3 7 23 12 40 10 34
3 13 1 5 11 50 6 27 1 5
2 15 6 46 5 39
8 38 3 14 7 34 3 14
4 12 1 3 2 6 10 30 5 15 11 34
2 7 5 17 6 20 10 33 7 23
1 3 4 12 3 9 7 21 3 9 15 46
27 82 6 18
2 8 3 11 22 81
1 11 8 89
1 3 31 97
1 3 32 97
25 100
26 100
32 100
33 100
65 100


- -






Florida Agricultural Experiment Station


EXPERIMENTAL RESULTS
As 25 plants seemed quite adequate for the data, the original
planting of 35 plants gave a leeway for loss of some of them.
Where all seven plants in a plot survived the data were taken
on the five middle plants. Shortly after the plants were set in
Plantings No. 3 and No. 4, infested roots and soil were spread
and cultivated into the ground.
When the plants were taken up they were examined and
classified as follows: (1) not infested, (2) very lightly infested,
(3) lightly infested, (4) moderately infested, 5) heavily infested,
and (6) very heavily infested. This classification was based
on the number and size of the galls. In the first group no galls
were found; in the second group were placed the plants which
showed one or a few scattering galls; in the third the plants
that had a number of small galls; in the fourth group the galls
were either more numerous or larger than in the third; in the
fifth a large percentage of the roots were infested with large
galls; and in the sixth group practically all roots had a large
number of large galls.
Tables 1 to 4 show the total number of each kind of plant
used in the four plantings and the number of plants and per-
centages that come in the classifications just described.
TABLE 2.-TOTAL NUMBER OF EACH KIND OF PLANT, DEGREE OF INFESTA-
TION BY ROOT-KNOT, AND NUMBER AND PERCENTAGE OF PLANTS IN EACH
GROUP FOR PLANTING NO. 2, SPRING OF 1933.
Number of Plants and Percentages Infested
Plants I Very Heavily Mod. Lightly Very Not
SHeavily Infested Infested Infested Lightly Infested
Infested Infested
SNo. % No. % No. % No. % No. % No. %
Celosia ........................... 50 50 100
Morning-glory................ 50 36 72 9 18 3 6 2 4
Centaurea...................... 19 12 63 4 21 3 16
Scarlet climber............50 6 12 17 34 12 24 15 30


Sunflower........................ 50
Moonflower .................... 25
Arctotis............................ 35
Blue laceflower............. 28
Portulaca.................... 50
Vinca................................ 50
Giant zinnia ................ 42
Cosmos ........................... 39
Phlox................................ 50
Verbena ....................... 15
Torenia.......................... 22
Four o'clock................... 50
Small zinnia .................. 50
Calliopsis ........................ 10
Thunbergia ....... ......... 14
Gaillardia........................ 35
African marigold.......... 50


15 30
6 24
5 14
4 14


1 3


15 30
6 24
6 17
8 20
8 16
1 2
1 2
1 3
3 6


-------- '






Relative Susceptibility of Ornamentals to Root-Knot


TABLE 3.-TOTAL NUMBER OF EACH KIND OF PLANT, DEGREE OF INFESTA-
TION BY ROOT-KNOT, AND NUMBER AND PERCENTAGE OF PLANTS IN EACH
GROUP FOR PLANTING NO. 3, WINTER OF 1933.


Number of Plan
Plans -i Very Heavily
Plants j Heavily Infested
I :3 Infested
Z No. % No. % 1

Ann. sweet pea.............. 25 19 76 6 24
Lobelia .......................... 25 16 61 7 30
Centaurea...................... 25 17 68 5 20
Larkspur ...................... 4 3 75
Schizanthus................... 25 12 48 11 44
Calendula...................... 25 12 48 9 36
Gilia .............................. 25 9 36 7 28
Cynoglossum .................. 21' 3 14 10 48
Pansy ............................ 251 9 36 7 28
Snapdragon .................. 22 14 64 4 18
California poppy.......... 25 9 36 7 28
Dianthus......................... 25 11 44 2 8
English daisy .............. 251 4 16 5 20
Candytuft...................... 25 3 12 5 20
Dimorphotheca ............. 251 2 8 6 24
Hunnemannia ................ 17 3 18 4 23
Shasta daisy ............. 25 3 12 8 32
Nicotiana ...................... 25 2 8 5 20
Poppy ......................... 25 1 4 7 28
Gypsophila........ ........ 25 3 12 5 20
Petunia......................... 25 4 16
Mignonette....................i 25 6 24
Acroclinium.................. 25 I 4 1 4
Gerbera daisy............... 24 1 4
Stock................................ 25 1 4 2 8
Per. sweet pea.............. 25 2 8 3 12
Linaria ..........................1 23 2 9 2 9
Carnation........................ 25 3 12 2 8
Godetia......................... 241 1 4
Leptosyne.............. ... 16 1 6
Statice........................... 251
Phlox......................... 251
Calliopsis ........................ 25
Arctotis........................... 25 1 4
Michaelmas daisy.......... 25
Lupine............................. 15
Clarkia ....................... 3
Coreopsis ........................ 10
Four o'clock.................... 23
Alyssum .......................... 25
Gaillardia....................... 25 _


ts and Percentages Infested


Mod.
Infested
No. %C


Lightly
Infested
No. %


1 4


Very
Lightly
Infested
No. %


Not
Infested
No. %
























5 20
1 4
10 40
4 17
2 13
10 40
12 48
10 40
20 80
23 92
14 93
3 100
10 100
23 100
25 100
25 100






Florida Agricultural Experiment Station


TABLE 4.-TOTAL NUMBER OF EACH KIND OF PLANT, DEGREE OF INFESTA-
TION BY ROOT-KNOT, AND NUMBER AND PERCENTAGE OF PLANTS IN EACH
GROUP FOR PLANTING NO. 4, SPRING OF 1934.

Number of Plants and Percentages Infested


Plants



Gourd ............................
Balsam .......................
Dolichos .........................
Celosia .........................
Lobelia ........................
Nasturtium ..................
Amaranthus...................
Helichrysum ..................
Blue lace flower ..........
Morning-glory ................
Sunflower-..................-
Cardinal climber...........
Coleus ...........................
Moonflower ..................
Dimorphotheca ..............
Ann. chrysanthemum....
Petunia............................
Per. chrysanthemum....
Portulaca .........-............
Artemisia ......................
Cypress vine .................
Cynoglossum .................
Clarkia .......................
Liatris spicata ..............
Vinca.............................
China aster...................
Pentstemon ....................
Phlox nana comp...........
Blue torenia... .........
Phlox drm. stell.............
Globe amaranth ............
Big drum. phlox............
Dianthus....................
Alyssum ........................
Thunbergia ....................
Scarlet sage --.............
White torenia.............
Verbena ......................
Four o'clock....................
Blue sage.................
Zinnia -......................
Cosmos .......................
Ageratum......................
Evening primrose..........
Rudbeckia..................
Argemone........................
French marigold............
African marigold..........


2,S Very Heavily Mod. Lightly Very
E Heavily Infested Infested ed Infest Lightly
Ii Infested Infested
No. % No. % No. % No. % No. %

14 14 100
25 25 100
8 8 100
25 21 84 4 16
25 21 84 4 16
25 20 80 2 8 2 8 1 4
25 17 68 7 28 1 4
25 18 72 5 20 2 8
25 18 72 4 16 1 4 2 8
20 13 65 4 20 3 15
25 13 52 9 36 2 8 1 4
20 8 40 5 25 5 25 1 5
25 5 20 9 36 6 24 5 20
20 8 40 3 15 3 15 3 15 3 15
25 6 24 8 32 5 20 4 16 2 8
8 3 38 4 50 1 12
25 3 12 10 40 5 20 4 16 3 12
13 1 8 3 23 5 39 2 15 2 15
25 7 28 10 40 6 24 2 8
251 4 16 8 32 10 40 3 12
20' 6 30 6 30 2 10 4 20
151 2 13 3 20 8 53 2 13
13 1 8 5 38 3 23 4 31
9 1 11 2 22 4 44 2 22
25 2 8 8 32 8 32 7 28
25 2 8 3 12 14 56 5 20
25 1 4 1 4 4 16 8 32 11 44
25 1 4 6 24 3 12 11 44
25 13 52 10 40
25 1 4 3 12 5 20 10 40
25 2 8 1 4 2 8 16 64
25 1 4 1 4 7 28 9 36
25 1 4 1 4 5 20 10 40
25 5 20 18 72
25 1 4 7 28 10 40
20 20 100
25 21 84
25 1 4 1 4 11 44
15 8 53
10 5 50
25 1 4 7 28
25 2 8
25
25
25
21
25
25


Not
Infested
No. %


1 5







2 10



1 4

4 16
2 8
6 24
4 16
7 28
8 32
2 8
7 28

4 16
12 48
7 47
5 50
17 68
23 92
25 100
25 100
25 100
21 100
25 100
25 100














0* N
V 0 aV 0 io xee 7
.0 oin~ o. c.

Very g00 4 E 0 t Very
SInfeted Infested

e Ully fHeavily "




od. Mod
Infested MoInted.





Veryery
Lightly Lightly
Infested



Fig. 1.-Relative susceptibility of some ornamental plants to root-knot, as determined by four experimental plantings on
infested soil.
C-5





Florida Agricultural Experiment Station


The following method was used in summing up and rating
the plants for comparison. Arbitrary numbers were assigned
for each degree of infestation. They were: 0-not infested,
20-very lightly infested, 40-lightly infested, 60-moderately
infested, 80-heavily infested, and 100-very heavily infested.
Each plant was rated and the average for each kind of plant
found. Table 5 shows the rating for the different kinds of plants
for each of four plantings. Figure 1 shows the relative suscepti-
bility of the plants to root-knot as determined by the four
plantings.
A great variation in degree of infestation of the various plants
was noted. A few kinds of plants such as the marigolds seemed
to be 100 percent resistant to the root-knot, while in the cases
of gourd and celosia all the plants were heavily or very heavily
infested under the same conditions. Between these extremes
there was a great variation. In some species most of the plants
were free of infestation but a few were very lightly infested.
In other species, all degrees from no infestation to heavy infes-
tation were found. Some of this may have been due to the
degree of infestation of the nematodes in the soil, as there
seemed to be a great variation in numbers even in small areas.
However, there were cases of uninfested plants with heavily
infested ones on each side of them.


Fig. 2.-Whip-poor-will cowpeas, grown on the same area as experimental
planting No. 3, were dead within two and a half months after the highly
susceptible ornamentals were removed. In places where less susceptible
ornamentals were grown, the cowpeas had survived.






TABLE 5.-RATE* OF THE ROOT-KNOT INFESTATION IN THE FOUR PLANTINGS.


Scientific Name
Common Name (After "Hortus", L. H. Bailey)


Acroclinium ............-....................... Helipterum roseum ....................
Ageratum............................. .. Ageratum sp...... .........
Alyssum, sweet.......... ................. Lobularia maritima .......... ......
Amaranthus (molten fire)............... Amaranthus sp. -.....~.........-.... ..
Arctotis...................... ....... ................ Arctotis stoechadifolia ..... ... ...-.....
Argemone ........................................... Argemone sp. ......... .............
Artemisia ............................ ... Artemisia sacrorum viride .............
Aster, China ..-.......-- ...................... Callistephus chinensis -............
Balsam ....... ...... ........ ..... Impatiens balsamina ....-........-..
Blue lace flower (Didiscus).............. Trachymene caerulea ..-..............
Butterfly flower............................... Schizanthus sp. .................. .-
Calendula ......... ............. .......... Calendula officinalis ................
Calendula, radio................................. Calendula officinalis .-...... .......
Calliopsis ............. .................. .. Coreopsis tinctoris ...................
Candytuft......................................... Iberis umbellata .................... -...
Carnation .................................... Dianthus sp ................- ...............
Carnation, Marguerite ...................... Dianthus sp. ..........-................
Celosia........................................ ........... Celosia argentea var ............. ...
Centaurea................ ................ Centaurea cyanus ...............
Chinese forget-me-not ......................... Cynoglossum sp. ...................
Chrysanthemum, annual ..................... Chrysanthemum coronarium .........
Chrysanthemum, perennial---............... Chrysanthemum sp. ................
Clarkia ................................. .............. Clarkia sp. ..... ....................
Coleus ............................Coleus sp .................. ...........
Columbine.......... .......................... Aquilegia sp. ....................
Coreopsis...................................... Coreopsis lanceolata ......................
Cosmos .................................................... Cosmos bipinnatus .............................
Cypress vine............................................ Quamoclit pennata .................
Daisy, English.. ...................... Bellis perennis ...........................
Daisy, Gerbera ........................................ Gerbera jamesoni .........................
Daisy, Michaelmas .................................. Aster tradescanti .......................


Plantings
Winter Spring Winter Spring
of '32 of '33 of '33 of '34 Average

63 47 55
| 0 0
0 0 22 7.3
93 93
1 34 6 13.7
0 0
50 50
35 40 37.5
100 100
100 28 90 72.7
87 87
100 86 93
87 87
1 0 12 4.3
30 62 46
36 36
57 57
100 97 98.5
89 90 91 90
98 75 47 73.3
-- 65 65
59 59
0 45 22.5
S- 71 71
74 -- 74
0 0 0
O 10 2 4
50 50
67 67
2 46 24
S 2 1








TABLE 5.-RATE* OF THE ROOT-KNOT INFESTATION IN THE FOUR PLANTINGS.-Continued.

Scientific Name Plantings
Common Name (After "Hortus", L. H. Bailey) Winter Spring Winter Spring
________of'32 of'33 of'33 of'34 Average

Daisy, Shasta ....................................... Chrysanthemum maximum ........... 35 60 47.5
Dianthus................Dianthus sp ........................................ 68 22 45
Dimorphotheca ....... .............. ........... Dimorphotheca aurantiaca .............. 61 70 65.5 2.
Dolichos ................... .............. ... Dolichos sp .......................................... 100 100
Evening primrose........................... Oenothera lamarkiana ..................... 0 0
Four-o'clock ............. ............... Mirabilis jalapa ........................... 2 0 11 4.3
Gaillardia............................................... Gaillardia sp. ................................. 0 0 0 I
Gilia....................................................... Gilia sp. ... ......................... ........ ...... 77 77 1.
Globe amaranth......................... Gomphrene globosa ............................ 25 25
Godetia ..............................Godeta sp........... ........... ............... 39 33 36
Gourd ...................................... Cucurbita sp ..................................... 100 100
Gypsophila (Baby'sbreath)................ Gypsophila sp. .................................. 99 54 76.5
Helichrysum............... ....... Helichrysum sp............................... 98 93 95.5
Hollyhock ........... .................. Althaea rose ...................... 82 82
Hunnemannia ................... .............. Hunnemannia fumariaefolia ............ 60 60
Lantern ground cherry..................... Physalis francheti ............................ 40 40
Larkspur..................................... .... Delphinium sp. .................................... 90 90
Leptosyne ........................................... Coreopsis sp. ................................. 29 29
Liatris.......................... Liatris spicata .............. ........ 44 44
Linaria ................................................... Linaria sp ......................... .......... 71 41 56
Lobelia............. ........... ........ ........... Lobelia erinus ...................................... 94 91 97 94
Lupine.............. ...................... Lupinus sp ..... ............................. 1 1
Marigold, African............... ........... Tagetes sp. .................................... 0 0 0
Marigold, French .................................. Tagetes sp. .......................... 0 0
Matricaria ....................................... Matricaria sp .............................. 80 80
Mignonette ...................................... Reseda odorata .................................. 50 50
Moonflower ..................................... Calonyction sp. .............................. 46 70 58
Morning-glory .......................... ......... Ipomoea sp. ................................. 92 90 91
Nasturtium................................... Tropaeolum sp. ....................... 76 93 84:5
Nicotiana ......................................... Nicotiana alata ................................ 59 59
Pansy........................................................ Viola tricolor ....................... ........ 98 75 86.5







TABLE 5.-RATE* OF THE ROOT-KNOT INFESTATION IN THE FOUR PLANTINGS.-Continued.

Scientific Name Plantings _
Common Name (After "Hortus", L. H. Bailey) Winter Spring Winter Spring
of'32 of'33 of '33 of '34 Average

Pentstemon...... .............................. Pentstemon sp. ................................... 38 38 C
Periwinkle ---......................... ..... .... Vinca rose ........ ---.. ................- 16 44 30
Petunia ....................................... Petunia hybrida ............................... 39 51 65 51.7 S
Phlox, Big Drummond........................ Phlox drummondi ........................... 33 6 14 24 19.3 2
Phlox, Dwarf........................................... Phlox nana compact .....--....--...... -- 31 31
Phlox, Starred .............. .................... I Phlox drummondi stellaris -- 26 26 .
Pink---- ------- ................................ Dianthus sp. ...................................... 29 29 Z.
Poppy ....................................................... Papaver sp. ........................................ 56 56 .
Poppy, California......................... Eschscholtzia californica ............... 69 72 70.5 Z
Portulaca .............................. ...... Portulaca sp. ........ .... ......-- 21 58 39.5
Rudbeckia......... .......... ................... Rudbeckia sp. --..-................... 0 0 "
Sage, blue ............................ ................ Salvia farinacea ......... --.. -..-.. -------- 10 10 )
Sage, scarlet ........................................... Salvia splendens ...........- --..........- 20 20 -
Salpiglossis ...................... ............ ..... Salpiglossis sinuata ................84 84
Scarlet climber ................................ .... Quamoclit sloteri ............. ................. -66 76 71
Snapdragon .................................... Antirrhinum majus .......................... 93 74 83.5 M
Statice................................ .................. Lim onium sinatum ........................... 18 -- 18
Stock ......................................................... Matthiola sp. ------- --16 45 30.5 P
Sunflower........................................... Helianthus annuus .. ........... 69 62 87 72.7
Sweet pea, annual.................................. Lathyrus odoratus .--..- ....----------.. 97 95 96
Sweet pea, perennial ............................ Lathyrus latifolius ..--....................... 42 42
Thunbergia................... .................. Thunbergia sp. ..............--.--- 22 22
Torenia, blue............................................ Torenia fournieri ...-.......................... 4 29 16.5
Torenia, white....................................... Torenia sp. ............. .....-- -.... ---- 17 17
Verbena................................ .. ......... Verbena sp ...........-............................ 63 5 13 27
Zinnia, giant ............................................ Zinnia elegans ................................... 11 11 s
Zinnia, small ............................................ Zinnia elegans .................................... 5 2 7 4.7 0
0 = not infested, 20 = very lightly infested, 40 = lightly infested, 60 = moderately infested, 80 = heavily infested,
and 100 = very heavily infested.






Florida Agricultural Experiment Station


FACTORS OF INFESTATION
In some of these cases there was indication that wide varia-
tion in susceptibility to nematode attack may exist within the
same kind of plant. In the Dianthus group there was a wide
range of susceptibility, either between different types or indi-
viduals of the same type. By careful selection, highly resistant
strains might be found or developed with some of these plants.
Some types of plants seem to exhibit considerable tolerance
to the attacks of the nematodes. The roots may have great
masses of galls and yet the plant may be quite vigorous. How-
ever, with plants of this type the supply of water seems to be
a very important factor. If the ground becomes dry these plants
wilt very badly. Snapdragons and Centaurea are examples.
Temperature is important in the root-knot problem. There
are at least two factors involved. The development of the nema-
tode is greater in spring and summer than in winter, so that
a plant which may not be heavily infested during the winter
may be so heavily attacked as to be greatly injured or killed
during warmer seasons. The warmer weather is, also, unfavor-
able to some kinds of plants so that their vitality is lowered
and they are more readily injured by root-knot.
RELATIVE SUSCEPTIBILITY
Below is a list of ornamentals grown during the four plant-
ings. These plants have been listed in the order of their suscep-
tibility to the attack of the nematode as shown by the plantings,
taking into consideration the damage to the plants. For the
most part they are listed according to the method of rating
discussed previously. However, that order is changed in some
cases where one kind of plant shows more damage than a more
heavily infested one, i.e., less tolerance.

Not infested Cosmos
Marigold Zinnia
Coreopsis Sweet alyssum
Argemone Torenia
Rudbeckia bicolor Thunbergia
Ageratum sp. Blue sage
Evening primrose Arctotis
Gaillardia Phlox
Phlox
Very lightly infested Statice
Michaelmas daisy Scarlet sage
Lupine Globe amaranth
Calliopsis Gerbera daisy
Four-o'clock Vinca







Relative Susceptibility of Ornamentals to Root-Knot


Stock
Leptosyne

Lightly infested
Godetia
China aster
Pentstemon
Dianthus
Portulaca
Verbena
Lantern groundcherry
Perennial sweet pea
Liatris spicata
Clarkia
Shasta daisy
Candytuft
Mignonette
Cypress vine
Artemisia
Petunia

Moderately infested
Acroclinium
Linaria
Poppy
Moonflower
Perennial chrysanthemum


Very heavily infested
Schizanthus
Morning-glory
Larkspur
Lobelia
Helichrysum
Amaranthus
Calendula
Balsam
Blue lace flower
Annual sweet pea
Celosia
Dolichos
Gourd


Nicotiana
Hunnemannia
Annual chrysanthemum
Dimorphotheca
English daisy
Scarlet climber or
Cardinal climber
California poppy

Heavily infested
Coleus
Aquilegia
Helianthus
Chinese forget-me-not or
Cynoglossum
Gypsophila
Gilia
latricaria
Nasturtium
Snapdragon
Hollyhock
Salpiglossis
Pansy
Centaurea
Under dry conditions heavily in-
fested plants of the last 6 in this
group wilt seriously.


Some plants very badly damaged


Some plants greatly stunted
Most plants greatly stunted


Plants very badly stunted
Most of plants badly damaged, some killed
.' 44 '' "t




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