CIRCULAR 118 B
Revision of nol
FLORIDA COOPERATIVE EXTENSION SERVICE
INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES
UNIVERSITY OF FLORIDA, GAINESVILLE
POTATO PRODUCTION GUIDE (Revision)
The purpose of this guide is to present general
commendations for the production of potatoes
SFlorida. For details on local application of
these practices, see your county extension agent.
Additional information on potato production can
e found in the following publications: University
f Florida, Ag. Exp. Stations Circular S-206 and
agricultural Extension Service Circulars 193, 196
nd 225. Since Extension circulars are revised
com time to time, be sure to obtain the latest
ACREAGE AND HARVEST PERIODS*
counties harvested harvest period
lagler 2,800 Apr.-June
t. Johns 17,900
illsborough 880 Apr.-May
ollier, Lee & Hendry 1,570 Jan.-Apr.
aim Beach (West) 1,050 Dec.-May
ade 7,770 Feb.-Apr.
ll Others 930
From-Fla. Ag. Statistics, 1970 Vegetable Summary.
YIELDS, COSTS AND RETURNS*
Five-Season Average (1964-65 to 1968-69)
tem Dade Hastings Lee
ags/acre (100 lbs.) 168 139 156
rowing costs $375.90 $307.83 $398.61
harvest & market costs $191.79 $137.54 $202.19
otal costs $567.69 $445.37 $600.80
,rop sales $707.46 $486.77 $667.07
leturns/acre $139.77 $ 41.40 $ 76.27
'From-Univ. of Fla., Ag. Econ. Report 15, February,
1971, by D. L. Brooke.
Good quality seed potatoes are necessary to in-
sure success in the production of this crop in
'lorida. Growers should always use certified
reed. In addition, care should be taken to protect
seed stock from cold injury, overheating, etc., dur-
ng the period between arrival on the farm and
Sebago.-Standard white variety. Excellent fi
chips. Smooth, good shape. Some disease resis
Red La Soda.-A dark red skinned, attractive
fairly smooth, white flesh, good yielding, mediu:
early variety of high quality.
Pungo.-Round, white variety, recommend(
only where corky ringspot virus is present in tl
La Rouge.-Medium to late-maturing, smoot
attractive, red skinned, white to cream color(
La Chipper.-Medium maturing Irish Cobble
type, white skin with very white flesh. Good chi]
Kennebec.-White, elliptical to oblong tube
with shallow eyes. Good chipper.
Planting Dates Days to Diggil
North Florida-Jan.-Feb. ...................... 85-110
(Hastings: Dec. 20-Feb. 15)
Central Florida-Dec.-Feb. .................. 85-110
South Florida-Sept.-Dec. ...................... 85-110
(Everglades: Jan. 10-Feb. 15 and Sept. 15-Oct. 5)
(Lee County: Oct. 10-Oct. 31)
(Dade County: Nov. 1-Nov. 20)
Spacing and Seeding
North & Central
Distance between rows
Distance between plants
36" to 42"
8" to 12"
3" to 4"
1%1 to 2 ozs.
36" to 42"
6" to 9"
3" to 4"
1% to 1% oz
Potatoes are susceptible to nematode injury
Planting in infested soils should be avoided when
ever possible. Fallow cultivation, crop rotations
flooding, etc., are possible means of controlling
nematodes. If soils heavily infested with plan
parasitic nematodes must be used, they should b
fumigated as suggested in the following table.
Nematicides-Rates and Use
Fl. oz./ 1000
chisel linear ft.
per 1000 Gal./Acre3 (Any Row
lematicide Gal./Acre linear feet (36" Row) Spacing:
hidden D 20-25 59-73 8-10 73-90
lone 15-20 43-59 6- 8 53-73
DB4 4.5-6.0 13-18 1.5-2.0 13-18
orlex5 20-25 59-73 8-10 73-90
overalll rate per acre based on 12-inch chisel spacing.
or organic (peat and muck) soils, rates should be in-
these gallonages are given as a guide to determine total
mount of chemical needed for a field. Closer row spacing
ill require more chemical per acre; wider row spacing
May cause injury to seedlings in some areas under certain
rhe rates listed are for root-knot nematode control. Ef-
ective control of sting nematodes can be obtained with
0 gal./A overall. Vorlex at rates of 35-40 gal./A overall
effective against a complex of soil diseases, insects and
Chemical treatment for breaking the "rest pe-
iod" of the potato tuber is not recommended,
except for the fall-planted crop in the Everglades.
In those cases where need for breaking dor-
ancy has been established, the following is one of
several methods recommended: Dip freshly cut
eed-pieces in a solution of 3 pounds of ammonium
hiocyanate in 50 gallons of water; allow them to
rain and stack loosely in well ventilated sheds.
lant treated seed-pieces following day.
The use of potassium gibberellate is suggested
or trial purposes in breaking dormancy on pota-
oes. Dip freshly cut seed-pieces in a solution of
potassium gibberellate (1 ppm for all varieties,
except 2 ppm for Red La Soda). Potassium gib-
erellate may be combined with the formaldehyde
treatmentt for scab or seed-piece decay treatments.
Plant seed immediately after treatment.
Placement.-Fertilizer, applied at seeding or
luring early stages of growth, should be placed in
bands 2 to 3 inches to each side and at the level o
the seed-piece or the growing tips of roots.
Timing.-The basic application of fertilizer ma:
be applied before planting, during planting, short
ly after planting or in split application at any tw
or all three of these times. Supplemental fertili2
er may be applied whenever needed during th
growing season and especially after heavy, leach
Soil pH and Minor Elements.-Optimum pl
range for potato production is between 5.5 and 6.
If possible, pH should be maintained below 5.5 i:
those areas where scab is a problem. Minor ele
ments may be needed on certain soils, especially
on those with pH 6.0 or above. Manganese an
zinc, as well as the other minor elements, may b
applied to the soil in fertilizer or to the foliage a
fungicidal or nutritional sprays or dusts.
On the high pH soils in Dade County, magnet
sium and manganese are usually added to the fer
tilizer at planting. In addition to manganese
other minor elements may also be needed.
Basic Application Supplemental Applications
Actual lbs./acre1 Each application No. of
Soil N-PO,-KO N-P,0O-K,O Application
(Irrigated) 150-200-200 30- 0-30 1 to 3
(Unirrigated) 120-160-160 30- 0-30 0 to 2
Muck & Peat4 0-160-240 -
Marl 60-120-120 30- 0-30 0 to 2
Rockland5 30- 60- 60 15-30-30 1 to 2
1Amounts of N-P-K suggested here should be reduce
proportionately when soil tests show high residuals in th
2Includes all mineral soils (except marl and rockland'
having a dependable supply of moisture.
3Includes all mineral soils (except marl and rockland.
not having a dependable supply of moisture.
40n new peat, make a broadcast application of 15 lbs
of CuO, 10 lbs. of MnO and 4 lbs. of B203 per acre before
any crop is planted.
5Production of potatoes is not recommended on Rock
6Where leafroll has been observed, increase proportion
of nitrate-nitrogen to 30-35 percent of total nitrogen. A!
an alternative, make supplemental application of nitrate
nitrogen as a sidedress. Supply 50 percent of the tota
potash in a form other than muriate.
CHEMICAL WEED CONTROL
Before attempting wide-scale use of a new her-
icide, test it on a small scale for one or more
For preemergence weed control, it is especially
important that the seedbed be prepared properly
beforee treatment with herbicides. The seedbed
should be firm, smooth and free of crop residues.
xood soil moisture is necessary for most herbicides
;o be effective.
After the herbicide is applied, treated soil
should not be disturbed unless otherwise specified
ror the herbicide. Cultivate with care to prevent
untreated soil from being moved to a treated area.
Herbicides-Rates and Use
Time of Ingredients)2
Application Sandy Muck
herbicides to Crop' Soils Soils Remarks
)alapon Pre- 7.4 For control of
Dowpon) planting perennial
grasses. Apply to
weed foliage and
then plow under
2 weeks later.
PTC Preemer- 4 to 6 Incorporate and
Eptam) gence plant immed-
iately or incor-
porate just before
use on marl soils,
CDAA+ Preemer- 3 + 3 3 + 3 If not used pre-
CDEC gence emergence, this
(Randox combination may
and be used at lay-by.
Vegadex) CDAA and CDEC
may be used
separately pre- or
DCPA Preemer- 10 1/ -
Dinoseb Preemer- 3 to 6 3 to 6 Apply at least
(Premerge, gence one day before
Sinox PE) crop emerges.
Diphenamid Preemer- 4 to 6 -
Dalapon3 Postemer- 3.7 Apply after last
are a problem.
ally to base of
crop plants. Do
not apply to red
EPTC Postemer- 4 Incorporate im-
(Eptam) gence mediately after
ply after last
cultivation or n<
later than 45
days before har-
for marl soils,
Meta- Preemer- 2 Single applica-
bromuron3 gence tion per season.
(Patoran) Do not apply
within 90 days
1All treatments are "preemergence" to weeds unles
stated otherwise under "Remarks."
2The amounts (active ingredients) listed here are fo
overall applications. For band treatments, reduce th
SThese chemicals are suggested for use on a trial basi
The amount of insecticides and fungicides rec
ommended as sprays under "Insect Control" an<
"Disease Control" are for 100 gallons of water
"Minimum Days to Harvest" means the minimun
number of days that should be allowed between
last foliar application and harvest.
Spraying is recommended over dusting for pes
control. The amount of spray or dust required
for adequate coverage varies according to size o
the plants. Generally, 75 to 150 gallons of spra:
or 20 to 35 pounds of dust are sufficient for gooi
coverage. Pressure in spraying should not exceed
250 psi. Nozzles should be arranged to give goo4
coverage of all surfaces of the leaves and stems.
PRECAUTIONS: Read pesticide label:
thoroughly before opening container, and observe
all safety precautions. Dispose of empty con
tainers promptly and safely. Information is give
on recommended pesticides and minimum days be
tween last application and harvest. There will bi
changes and cancellations; therefore, the grower
is urged to keep abreast of developments through
county agents, experiment stations, industry, etc
Insecticides-Rates and Use
Insects Spray Dust Harvest
Aphids' Azodrin 5E, 13 fl. ozs. 7
Demeton (Systox) 2E,
11/ pts. 21
11/ pts. NTL5
11/2 pts. 7
Armyworms, Parathion 4E, 1 pt. Parathion 5
Loopers, Azodrin 5E, 13 to 2%
26 fl. ozs. 7
theirr Phosdrin 2E, 1 pt. 1
Cater- Thiodan 2E, 1-2 qts. NTL
pillars Toxaphene 8E, 1-2 pts. Toxaphene
Cucumber Guthion 2E, 1 qt. 7
beetle Thiodan 2E, 1-2 qts. NTL5
Potato Sevin 80% WP, 1'4 lbs. NTL
Beetle Thiodan 2E, 1-2 qts. NTL
leaf-Footed Guthion 2E, 1 qt. 7
Plant Bug, Parathion 4E, 1 pt. Parathion 2% 5
5reen Phosdrin 2E, 1 pt. 1
Stinkbug Thiodan 2E, 1-2 qts. NTL
Leaf Azodrin 5E, 13 fl. ozs. 7
Miners2 Diazinon 4E, %-1 pt. Diazinon 14
Dimethoate 2.67E, 2%
%/-1 pt. NTL
Guthion 2E, 1 qt. 7
Cutworms3 Chlordane-See footnote (3) below.
Wire- See footnote (1) and (4).
1Systemic Insecticides for Soil Application.-Phorate
Thimet) and Di-Syston will give some control of aphids
m potatoes. Di-Syston is more effective, however, neither
material will give control for the full-growing season.
Apply Thimet or Di-Syston at the rate of 30 pounds of
0% granules per acre at planting in the seed piece
In tests against Conoderus wireworms in the Hastings
rea, these materials applied as above in the seed piece
urrow have given satisfactory control. In limited tests
against light infestations of Melanotus wireworms in the
homestead area, phorate (Thimet) applied as above in
;he seed piece furrow has given satisfactory control.
2 Leaf Miners. -Watch closely for leaf miners. Apply
insecticides twice a week to small plants when there are
heavy migrations of adult leaf miners from nearby aban-
doned host vegetable fields, or on older plants when
weekly applications are not giving control. Diazinon has
not been effective in the Homestead and Lower East
Coast areas in recent years. Parathion will usually give
control in Central and North Florida.
3 Cutworms.-Apply chlordane at 2 pounds active in-
gredients (5 pound of 40% WP or 20 pounds of 10% dust
or granules) per acre to the soil surface before planting
if cutworms are known to be present. Do not disturb soi
for three to five days. A 2% chlordane bait can be used a
above at 20 to 40 pounds per acre. If cutworm damage
to young plants is noted, baits should be used at once
Regular applications of approved pesticides, including
parathion, toxaphene, etc., for control of foliage insect
will prevent the establishment of cutworms.
A home-made bait can be prepared by thoroughly mix
ing 5 pounds of 40% chlordane WP with 100 pounds o
wheat bran. Moisten bait slightly with water and appl:
in late afternoon. Use freshly mixed baits.
4 Wireworms.-Apply parathion or diazinon at 2 pound
active ingredient per acre on mineral soils; on the mai
soils of Dade County use 4 pounds of parathion or diaz
inon; on organic soils apply parathion at 5 pounds o
diazinon at 4 pounds active ingredient per acre. Dis
tribute evenly over the soil surface 2 or 3 weeks before
planting and immediately mix into the upper 6 inches o
SNTL.-No time limitation.
Numerous viral, bacterial and fungal disease
are controlled by always planting certified seed.
Seed-piece treatment.-Potato seed-piece treat
ments are often helpful in obtaining better stand:
and yields. Effective materials for seed treat
Polyram, 7% dust 1-1.5 lbs. per 100 lbs.
seed, or Captan, 71/2% dust 1 lb. per 100
lbs. of seed or Dithane M-45 or Manzate
200, 8% dust 1 lb. per 100 lbs. of seed.
NOTE. Potato seed pieces should be planted ai
soon as possible after cutting and treating.
CAUTION: Do not use treated seed for food o0
Corky Ringspot.-This disease is caused by
soil borne virus that is transmitted by nematodes
Pungo is highly resistant to corky ringspot and ii
suggested for planting in infested soil.
Disease Spray to Harves
Early Blight, Maneb 80% 1/2 lbs., or NTL
(Alternaria Dithane M-45 80% 112 lbs., or NTL
Late Blight, Manzate 200 80% 1/2 lbs., or NTL
(Phytophthora Polyram 80% 11/ lbs. NTL
In South Florida, begin spraying for late bligh
when plants have emerged and continue at foul
to five-day intervals.
In the Hastings area, begin spraying when the
ants are 6 to 8 inches high, if late blight does
t show earlier, and continue at five- to seven-
y intervals; or use a more economical method
control by spraying the plants following eight
nsecutive days when the seven-day average
ily temperatures range from 50 to 770F. and
e ten-day total rainfall is 1.01 inches or greater.
Then the latter method is used, intervals between
rayingg may vary from 5 to 14 days or more de-
nding upon the severity of late blight and the
ration of periods when temperatures and rain-
ll favor its development.
Scab (Streptomyces scabies).-Use of certified
eed and crop rotation, and holding soil pH below
.0 will assist in controlling scab.
Sclerotinia (Sclerotinia sclerotiorum).-Flood-
ig fields for five or six weeks during summer
months will reduce the number of sclerotinia in
On marl soils where sclerotinia has attacked the
previous crop, apply 400 to 600 pounds of calcium
yanamid per acre at least 30 days before plant-
g. Distribute evenly and thoroughly mix with
e surface soil. Cyanamid is not necessary if
oil has been flooded three or more weeks during
Potatoes are harvested in Florida before the
plants (vines) have died down completely. If
otato tubers are harvested from such plants, the
ubers are likely to "skin" badly during the pro-
ess. To avoid this problem, the vine should be
illed ten to twenty days before harvesting. The
ines can be killed by:
1. Mechanical means-Vines can be killed by
rotary mowing or rotobeating.
2. Flame-Fuel oil or manufactured gas can be
used to flame the vines.
3. Chemicals-The most common method of
vine-killing in Florida is the use of materials as
vine-dessicants (vine-killers). The three most
-ommonly recommended materials are ametryne,
paraquat and DNBP. Use these materials as rec-
ommended on the label.
Materials such as petroleum solvents and others
labelled for potatoes in Florida may also be used.
HARVESTING AND HANDLING
Potatoes must be harvested and handled pro]
early to maintain quality and appearance. Vinm
should be killed at least ten to twenty days befoi
harvest to allow skins to set. Avoid bruising i
the harvesting operation. Bruising during hai
vest can be significantly reduced by slowing tt
forward speed of the mechanical harvester an
covering the chain links with a cushioning mi
Potatoes should be handled rapidly from th
harvester to the packing house. Avoid long ei
posure to hot, drying conditions. Check packin
house equipment carefully and eliminate cond
tions responsible for scuffing and bruising during
washing, grading and bagging.
The use of trade names in this publication is solely fq
the purpose of providing specific information. It is not
guarantee or warranty of the products named and doi
not signify that they are approved to the exclusion 4
others of suitable composition.
James Montelaro, and M. E. Marvel with cooperatic
of the faculty of the Institute of Food and Agriculturn
Sciences. Special assistance was provided by Mr. J. I
Brogdon, Dr. R. S. Mullin and Dr. D. W. Dickson.
COOPERATIVE EXTENSION WORK IN
AGRICULTURE AND HOME ECONOMICS
(Acts of May 8 and June 30, 1914)
Cooperative Extension Service, IFAS,
University of Florida and
United States Department of Agriculture, Cooperating
Joe N. Busby, Dean