From: Brian Lo <dragon@csulb.edu>
Newsgroups: rec.gardens
Subject: FAQ: Carrots
Date: Wed, 1 Mar 1995 14:50:36 -0800
CARROTS (Western Oregon)
Daucus carota
Types
Paris market (approximately 60 days): Round to "top-shaped" roots
averaging 2-3" in diameter. Grown for specialty fresh markets.
Amsterdam forcing (approximately 65 days): Roots are small to medium in
size (ave. 5"), slender cylindrical shape, blunt tipped, small core and smooth
skinned. Foliage and crown are small. Grown for bunching and as a quick
maturing crop for market or cello-paking. Also used for freezing and canning
especially for "baby carrot" packs.
Nantes (approximately 70 days): Roots are medium in size (ave. 6"),
cylindrical, generally with a slight shoulder, blunt tipped but sometimes
tending to taper. Intermediate in foliage and crown size. Quality is between
Amsterdam forcing and Berlicum. Because of its high sugar content and
tenderness, some varieties of this type have a tendency to split under late
season western Oregon conditions. Grown for cello-paking, bunching and
processing.
Imperator (approximately 100 days): Very long (ave.9-10"), tapered,
slender roots, small core, excellent color, smooth skinned. Foliage is
intermediate with a small crown. Grown for market, often bunched, and
sometimes for processing, primarily for sliced packs.
Berlicum (approximately 100 days): Roots are large (ave. 8-9"),
cylindrical or only slightly tapering, resembling a large Nantes. Grown
mainly for processing.
Danvers (approximately 80 days): Roots average 7", intermediate between
conical and cylindrical. Upper portion of the root is tapered toward the
crown. Pointed or somewhat stumped root tip. Matures about the same time as
the Chantenay group.
Chantenay (approximately 80 days): Roots are medium size (ave. 5"),
conical stump -rooted. Generally good core and flesh color. Moderate skin
texture. Usually shorter than Nantes but foliage size is between Berlicum and
Autumn King. Used widely for canning, freezing and dehydrating. Processed
where a multipurpose carrot is needed for slicing and dicing. Not generally
used for fresh market.
Autumn King (approximately 100 days): Roots are very large (ave.
10-12"), tapering, usually with broad shoulders. Core and flesh color are
generally inferior. Skin texture is rough. Late ripening and heavy yielding.
Foliage and crowns are large and vigorous. Strong flavored. Grown mainly for
certain fresh markets.
VARIETIES
Fresh market:
Bunching: Royal Nantes, Scarlet Nantes (Nantes types), Pioneer; Gold
Pride (long). For trial: Favor F1 (nantes type), Parano, Merida, Starca,
Primo, Tip Top (see note below), Imperator 58 (for deep soils only).
Cello-pack or storage: Six-Pak (cylindrical), Six-Pak II (slightly
tapered), Pak Mor, Gold Pride (long). For trial: Caropak, Orlando Gold,
Merida, Starca, Primo.
Baby carrot: Cello bags of fresh baby carrots are becoming popular.
These are primarily "manufactured" (cut and peeled) from undersized carrots,
or pieces of carrots intended for other packs. Because of the large demand
for this product, growers are planting high density carrots for this purpose
also. True whole "baby" carrots are more costly and difficult to produce,
harvest and handle. Varieties used for baby whole are Amsterdam strains:
Minicore, Grace, Indu, Amca, Amstel, Verona, Colora.
Specialty (high vitamin A): BetaIII (3-5 times higher in beta carotene,
the precursor of vitamin A); Ingot (long Nantes type, also with high beta
carotene, suggested for bunching).
Processing: Processors specify varieties. Some that have been grown are:
Baby whole - Amsterdam strains: Minicore, Baby Spike, Grace, Indu, Amca,
Amstel, Verona, Colora.
Slicing - Gold Pride, Orlando Gold, Hipak, Sixpak, Pioneer. For trial:
Lucky B, Merida, Starca, Primo.
Dicing - Royal Chantenay, Red Cored Chantenay, Danvers 126 and the
hybrids Spartan Bonus 80 and Chantenay Supreme. For trial: Sytan (see note
below).
Multipurpose - Danvers 126, Royal Chantenay and the hybrids Spartan
Bonus 80, Hipak, Lucky B, Mark II and Chantenay Supreme.
Novelty: Thumbelina, Orbit (round "Paresian market" types).
NOTE: Research reported in England indicates that the Nantes type
variety Tip Top (Breeders Seed Ltd.) and the Danvers type variety Sytan
(Clause Ltd.) showed resistance to carrot rust fly.
SEED COMPANIES
Abbott & Cobb Inc. POB F307, Feasterville, PA 19047
Asgrow Seed Company, POB 5038, Salinas CA 93915
Bejo Seeds, 1323 E. Fir St. Mount Vernon WA 98273
Breeders Seeds Ltd, Summerwood Lane, Halsall, Ormskirk, Lancs. L39 8KQ, U.K.
Clause Ltd, Charvil Farm, New Bath Road, Charvil, Reading RG10 9RU, U.K.
Daehnfeldt Inc. POB 947, Albany, OR 97321
Elsoms Seeds Ltd. Spalding, Lincolnshire, England PE11 1QG
Enza Seeds POB 7, 1600AA, Enkhuisen, The Netherlands
Ferry-Morse Seed Co. POB 4938, 555 Codoni Ave. Modesto, CA 95352
Harris Moran Seed Co. 3670 Buffalo Rd. Rochester, NY 14624
Nunhems Zaden, Canners Seed Corp. 221 E. Main St. Lewisville, ID 83431
Petoseed Co. Inc. P.O.Box 4206, Saticoy, CA 93007-4206
Rijk Zwaan POB 40 2678 ZG DeLier, The Netherlands
Rogers NK Seed Co. POB 4727, Boise, ID 83711-4727
Royal Sluis Inc. 1293 Harkins Rd. Salinas, CA 93901
Stokes Seeds Inc. POB 548, Buffalo, NY 14240
Territorial Seed Co. POB 157, Cottage Grove OR 97424
Vilmorin Inc. 6104 Yorkshire Ter. Bethesda, Maryland 20814
W. Osborne Seed Co. Int'l. 1679 Highway 99 South, Mount Vernon, WA 98273
Zenner Bros. Seed Co., Inc. 1311 S.E. Gideon St. Portland, OR 97202
SOILS
Deep well drained, sandy loam and muck soils of pH 5.5 to 7.0 are
desirable. A chisel plow is recommended to work these soils to a depth of 12
to 15 inches for good root penetration. Soils should be bedded to obtain
optimum drainage and maximum root length and smoothness.
SEED TREATMENT
Carrot seed numbers approximately 368,000 per pound. Use high quality
size graded and fungicide treated seed for optimum uniformity and performance.
Pelletized carrot seed is commonly used with precision spacing, and has been
found to be useful in improving size uniformity. A number of pelletizing
materials are available, differing in weight, cost and response to soil
moisture. Primed and coated seed is also becoming popular. Consult your seed
dealer about the availability of primed seed.
SEEDING
First fields of processing carrots may be seeded as early as mid-March
and the last about the first of July. Carrots for fresh market may be seeded
as late a July 20.
Generally 2-4 lbs. of seed are needed per acre for fresh market or
slicing carrots for processing. For dicing carrots for processing, 1-2 lbs of
seed are needed.
Plant populations per lineal foot of bed containing 2 scatter rows (or
4-6 lines), should be 12-(24) for dicing and 30-(40) for slicing or fresh
market carrots.
Ideally, raised beds 4-6 inches high, on 40 to 42 inch centers should be
used. Two scatter rows, or two multiple-line sets of 2 or 3 lines each, are
planted l2-l4 inches apart per bed (depending on bed width). Seeds are placed
1.3 to 2 inches apart. The lines of each set are spaced 1.5 to 2 inches
apart. In some cases, beds 72 inches apart, with 54 inch tops are used. In
such configurations, 4 double or triple-line sets are planted across the bed
top. When triple line sets are used increase the distance between seeds in
the center row. Wide beds can only be used in conjunction with overhead
irrigation.
Schematics of planting configurations described above:
__/!!!---!!!\___/!!!---!!!\__ __/!!!--!!!--!!!--!!!\__
two rows of triple-line sets four rows of triple-line
on 2 beds on 40 inch centers sets on a 70 inch bed
Where overhead irrigation and 40-42 inch beds are used, and where
modified potato diggers are used for harvest, it may be better to place the
line sets closer together and further from the edge of the bed. This would
reduce exposure of carrots in the outside lines to sunlight as the edges of
the beds erode, and reduce the necessity to cultivate between the sets. The
distance between the sets would be limited only by the distance needed between
planters as depicted below:
__/-!!!-!!!-\___/-!!!-!!!-\__
two rows of triple-line sets on
2 beds on 40 inch centers with
the sets placed closer together
Seeding with a precision seeder is recommended. Vacuum seeders such as
Stanhay or Gaspardo are becoming popular. The Stanhay belt planter has a
special shoe that plants 3 lines l.5 in. apart with each planter unit. The
seed belt is punched to drop 7 to 8 seeds per foot of line in the two outside
lines and 5 to 6 seeds per foot in the middle line. The Shanhay vacuum
planter also has the capability of planting 3 rows per planter unit. Each
vacuum plate meters seed to three separate lines. Lines are generally 1.5 to
2 inches apart and seeds are dropped about 1.5 to 2 inches apart down the
line, resulting in 4-6 seeds per foot of seed-line for dicers and 6-8 plants
for slicers. When triple line sets are used increase the distance between
seeds in the center row.
For non-bedded plantings use row spacings of l6 to 30 inches apart and
in-row stands of 10-20 plants per foot for dicing, or 20-30 plants per foot of
row for slicing (or fresh market) carrots. Use the lower plant populations
when planting single rows and the higher populations when planting scatter-
rows or multiple sets of rows.
The use of raised beds has been reported to reduce the incidence of
cavity spot, a complex disorder recently attributed to Pythium violae and
possibly Pythium ultimum. Outbreaks of these fungi are favored by excessive
soil moisture and temperatures of 61-72 F. Alfalfa, wheat, cauliflower,
broccoli, celery, cucumber, sugarbeet and watermelon also serve as hosts and
so should not preceed carrot, or be in rotation with it. Long rotations (3-4
years), good water management and prompt harvest are other suggested cultural
control measures.
BABY-WHOLE CARROTS
Although most "baby" carrots are manufactured from standard carrots as
noted above, whole baby carrots may also be produced. To obtain a uniform
size and shape of whole baby carrots, seed should be sown at high density and
distributed evenly in wide bands or solid beds. The seed need not be pelleted
but should be size-graded by the supplier.
A precision seeder is not necessary for planting this type of carrot.
Adequate results have been obtained by planting with a plate seeder at the
rate of 80 to 100 seeds per square foot. At these spacings as much as 20 lbs.
of seed per acre may be required. Planting multiple, staggered, scatter-rows
4 inches apart results in a "solid" stand when a 4 inch scatter shoe is used.
Staggered planters capable of planting multiple lines per unit (such as Beck
or Stanhay) might also be used. 30 or more lines would be needed on a 54 inch
wide bed. Beds are generally 72 inches center-to-center.
Schematic of spacing for whole baby carrots as described above:
/!!!!!!!!!!!!\___/!!!!!!!!!!!!\
Lines placed 1.5-2 inches apart on
beds that are 72 inches "on center"
FERTILIZER
A soil test is the most accurate guide to fertilizer requirements.
Good management practices are essential if optimum fertilizer responses
are to be realized. These practices include use of recommended varieties,
selection of adapted soils, weed control, disease and insect control, good
seed bed preparation, proper seeding methods, and timely harvest.
Because of the influence of soil type, climatic conditions, and other
cultural practices, crop responses from fertilizer may not always by accurate-
ly predicted. Soil test results, field experience, and knowledge of specific
crop requirements help determine the nutrients needed and the rate of appli-
cation.
Fertilizer applications for carrots should insure adequate levels of all
nutrients. Optimum fertilization is intended to produce top quality and yield
commensurate with maximum returns.
The following recommendations are general guidelines for Western Oregon
muck soils: the crop can use the following:
Nitrogen: 50-100 (N) lb./acre.
Phosphate: 100-160 (P2 05) lb/acre.
Potash: 80-150 (K2 0) lb/acre.
Sulfur: 30-50 (S) lb/acre.
For the early crop, band half the nitrogen and all the phosphate and
disc in the potash. Side dress the balance of the nitrogen after the crop is
6 to 8 inches tall. For the later plantings one may broadcast all the
fertilizer before seeding.
The following are recommendations for Western Oregon mineral Soils:
For carrots, fertilizer materials are usually broadcast and worked into
the seed bed ahead of planting.
The suggested fertilizer applications are based on a 24" row spacing and
20-25 plants per linear foot of row.
Recommended soil sampling procedures should be followed in order to
estimate fertilizer needs. The Oregon State University cooperative extension
agent in your county can provide you with soil sampling instructions and soil
sample bags and information sheets.
NITROGEN (N)
Rates of 75 to 120 lb of N/A are suggested. Broadcast N before planting
or part of the N can be applied as an early season top dressing. excess N can
cause splitting.
PHOSPHORUS (P)
Carrots require adequate available P for satisfactory growth. Broadcast
P and work into the seed bed before planting.
If the OSU soil test Apply this amount of
for P reads (ppm): of phosphate (P2 O5) (lb/A):
0 - 20 120 - 150
20 - 50 90 - 120
50 - 75 60 - 90
Over 75 0
POTASSIUM (K)
For optimum growth carrots require a good supply of available K.
Broadcast K and work into the seed bed before planting.
If the OSU soil test Apply this amount of
for K reads (ppm): potassium(K2 O) (lb/A):
0 - 75 120 - 180
75 - 150 90 - 120
150 - 225 60 - 90
Over 225 None
SULFUR (S)
Include 15-20 lb/A of S in the fertilizer pro gram for carrots. S is
sometimes contained in fertilizers used to supply other nutrients such as N,
P, and K, but may not be present in sufficient quantity.
Plants absorb S in the form of sulfate. Fertilizer materials supply S
in the form of sulfate and elemental S.
Elemental S must convert to sulfate in the soil before the S becomes
available to plants. The conversion of elemental S to sulfate is usually
rapid for fine ground (less than 40 mesh) material in warm moist soil.
Sulfur in the sulfate form can be applied at planting time. Some S
fertilizer materials such as elemental and ammonium sulfate have an acidifying
effect on soil.
The S requirements of carrots can be provided by:
1. The application of 15-20 lb S/A in the form of sulfate before plan-
ting.
2. Applying 30-40 lb S/A as fine ground (finer than 40 mesh) elemental
S the preceding year.
3. Applying coarser ground elemental S at higher rates and less fre-
quently.
MAGNESIUM (Mg)
To date, there have been no observed indications of yield response from
applications of Mg to carrots in the Willamette Valley. Trial applications of
10 to 15 lbs Mg/A are suggested with soil test values below 1 meq Mg/100g
soil.
Magnesium can also be supplied in dolomite which is a liming material
and reduces soil acidity to about the same degree as ground limestone.
Dolomite should be mixed into the seed bed at least several weeks in advance
of seeding and preferably the preceding year.
BORON (B)
Carrots require an adequate supply of B.
Apply 2 to 4 lbs of B/A (broadcast and disk in before planting).
Do not exceed the recommended rate of application. Excess B can be
toxic to carrots.
Boron should be broadcast uniformly on the soil. Never place boron in a
side-band close to the seed at planting.
OTHER NUTRIENTS
Responses of carrots to nutrients other than those discussed in this
guide have not been observed in western Oregon.
LIME
At present, lime is not generally recommended for carrots, as commonly
carrots are grown on sandy river bottom soils which usually have adequate
levels of calcium and magnesium.
A lime application is suggested where the soil pH is below 5.6.
If the OSU SMP Buffer Apply this amount
test for lime reads: of lime (T/A):
Below 5.2 4 - 5
5.2 - 5.6 3 - 4
5.5 - 5.9 2 - 3
5.9 - 6.2 1 - 2
Over 6.2 0
The liming rate is based on 100-score lime.
Lime should be mixed into the seed bed at least several weeks before
seeding and preferably the preceding year. A lime application is effective
over several years.
Some soils may have a fairly high OSU SMP buffer value (over 6.2) and a
low pH (below 5.3). This condition can be caused by the application of
acidifying fertilizer. In this case the low pH value is temporary and the pH
of the soil will increase as the fertilizer completes its reaction with the
soil. This temporary "active" acidity from fertilizer is encountered following
recent applications of most nitrogen fertilizer materials. Acidifying fertil-
izers also have a long term acidifying effect on soil which is cumulative and
leads to lower OSU SMP buffer readings.
Sandy soils to which fertilizers have not been recently applied some-
times record low pH and high SMP buffer values. In such cases, a light
application of lime (1 to 2 tons/A) should suffice to neutralize soil acidity.
For acid soils low in Mg (less than 0.5 meq Mg/100g soil) one ton/A of
dolomite lime can be used as a Mg source. Dolomite and ground lime stone have
about the same ability to neutralize soil acidity.
These recommendations are based on experiments conducted by Horticulture
and Soils departments researchers of the OSU Agricultural Experiment Station
and Extension Service as quoted form the OSU Fertilizer Guide FG 29.
ROW COVERS
Research in England and at OSU has shown that fresh market carrots re-
spond favorably to the use of floating row covers. These covers are available
in widths of up to 40 feet, and lengths suitable for most fields, allowing the
covering of about 1 acre per roll. Researchers in England have demonstrated
that the covers can be applied immediately after seeding and should be removed
at about the 7th true leaf to maximize earliness and yield without generating
too much top growth. OSU researchers have demonstrated that herbicides can be
applied through the row covers if necessary, and that herbicides applied prior
to covering are as effective as if applied without the covers.
IRRIGATION
Carrots grown in western Oregon may require 14-16 inches of water depen-
ding on seasonal variation, variety, and length of season.
Irrigation is critical during stand establishment. Frequent application
of water may be necessary to prevent crusting and also burning off of young
seedlings.
Soil type does not affect the amount of total water needed, but does
dictate frequency of water application. Lighter soils need more frequent
water applications, but less water applied per application.
HARVEST, HANDLING AND STORAGE
Processing carrots may be harvested from the first of August to the end
of November. The prime harvest period is from the end of August to October
25. For late harvest, carrot fields are limited to well-drained river bottom
soils, even so, harvest schedules are often disrupted by the weather. This is
the main reason considerable acreage of late carrots has shifted to the lower
Columbia Basin sandy soil areas.
Generally, custom-built, coulter pick-up, or modified potato harvesters,
rather than the belt pick-up Scott Viner harvesters are used in the harvest of
carrots for processing. Scott Viner types are generally used in harvesting
carrots for fresh market
Early fresh market carrots are harvested from early July to September
Late market carrots are harvested into December, and weather permitting as
late as the end of February. The prime harvest season for fresh market
carrots in western Oregon is from the first of August to the end of November.
Market, carrots must be over 5 inches long and between 3/4 and 1 1/2 inches in
diameter. Carrots harvested and handled in hot weather are more likely to
decay, and care should be exercised in handling to prevent wilting.
Processing carrtos are processed immediately after harvest, and not
usually stored. Most are scalped (tops removed) just prior to digging. A
reduction in yield of about 15-20% occurs when carrots are field scalped.
Scalped carrots, and those with inadequate, or frozen tops are harvested with
a coulter pick-up or a modified potato harvester. Carrots with intact tops
are may be harvested with a belt pick-up harvester that lifts carrots by their
foliage and allows tops to be removed in the same operation.
Average yields of fresh market and processing carrots combined were
reported to be about 500 cwt./acre for 1990, through 1992 in the Pacific
Northwest where most of the acreage is for processing. For the same period,
California carrot yields (which are mostly for fresh market) averaged about
300 cwt./acre.
For budgeting purposes, assumptions for processed carrot yields are
reported in the ENTERPRISE BUDGET section below.
STORAGE (Quoted from USDA Ag. Handbook #66):
Research in Michigan evaluating carrots that have been crowned or not,
washed or not and stored in a plastic lined bin or unlined bin found that
carrots stored best when untopped, unwashed and stored in plastic lined bins.
Ideal storage is at 32 F. and 99 % relative humidity. Carrots stored in
unlined bins can lose 6% to 10% of their weight. Topping carrots and washing
them also increased losses from decay. The worst treatment was topping,
washing and storing carrots in unlined bins.
Store carrots at 32 F. and relative humidity of 98 to 100 %. Mature
carrots are well adapted for storage and are stored in large quantities during
the fall and winter for both the fresh market and processing. Careful
handling during and after harvest to avoid bruising, cutting and breakage will
help ensure successful storage.
Mature topped carrots can be stored 7 to 9 months at 32 to 34 F. with a
very high relative humidity, 98 to 100 %. However, even under these optimum
conditions 10 to 20 % of the carrots may show some decay after 7 months.
Under commonly found commercial conditions (32 to 40 F.) with 90 to 95 %
relative humidity, 5 to 6 months storage is a more realistic expectation.
Prompt cooling to 40 F. or below after harvest is essential for extended
storage. Poorly pre-cooled roots decay more rapidly.
Carrots lose moisture readily and wilting results. Humidity should be
kept high. Carrots stored at 98 to 100 % relative humidity develop less
decay, lose less moisture, and remain crisper than those stored at 90 to 95 %
relative humidity. A temperature of 31 to 34 F. is essential if decay and
sprouting are to be minimized. With storage at 40 to 50 F., considerable
decay and sprouting may develop within 1 to 3 months.
Pre-storage washing of carrots may be desirable if they are harvested
under wet conditions. Many potential decay-causing organisms are removed by
washing. Also, clean, washed carrots allow freer air circulation. Air cir-
culation between crates of pallet boxes in which carrots are stored is desi-
rable to remove respiratory heat, maintain uniform temperatures, and help
prevent condensation. An air velocity of about 14 to 20 ft/min is adequate at
low storage temperatures.
Carrots for processing may be given a pre-storage dip treatment in a 0.1
% solution of sodium o-phenylphenate (SOPP) to effectively reduce storage
decay. The solution is not rinsed off after treatment.
Immature bunched carrot storage life is limited by the high perishabili-
ty of the tops. They should keep 2 weeks at 32 F. with 95 to 100 % relative
humidity. Contact ice is recommended to maintain freshness.
Immature or partially mature carrots should be topped and packed in
polyethylene consumer bags or 50 lb mesh bags for marketing. Most carrots for
the fresh market are of this type. If precooled promptly before packaging and
trimmed of all traces of leaf growth, they can be held 4 to 6 weeks at 32 F.
with 98 to 100 % relative humidity recommended. Film bags for carrots should
be perforated to allow ventilation and prevent development of off-odors or
off-flavors. Six 1/8th inch holes of 1 lb bags are suggested for ventilation.
Immature, topped carrots may be hydrocooled or packed in crushed ice for
cooling. Loose carrots can be hydrocooled from 75 to 40 F. in about 9 minutes
if the water is 33 F. If the carrots are in 50 lb mesh bags, the same degree
of cooling requires about 11 minutes. Sometimes top ice is used with bagged,
precooled carrots. The top ice provides some of the necessary refrigeration
and prevents dehydration.
Bitterness in carrots, which may develop in storage, is due to abnormal
metabolism caused by ethylene. This gas is given off by apples, pears, and
certain other fruits and vegetables and from decaying tissues. Bitterness can
be prevented by storing carrots away from such products. Also, development of
bitterness can largely be avoided by low-temperature storage, as it minimizes
ethylene production. Some surface browning or oxidative discoloration often
develops in stored carrots. The most immature carrots are the most suscepti-
ble to surface browning.
The highest freezing point for carrots is 29.5 F. Severe injury in car-
rots immediately after freezing is identified by lengthwise cracking and by
blistering caused by the formation of ice crystals immediately beneath the
surface. After thawing, a darkened and water-soaked skin is observed, and the
carrots are soft and flabby. Use of controlled atmospheres to extend storage
of carrots has not been promising. Atmospheres containing 5 to 10 % carbon
dioxide with reduced oxygen concentrations of 2.5 to 6 % caused a marked
increase in mold growth and rotting over that of carrots stored in air.
The most important decays of carrots in storage are gray mold rot (Bot-
rytis), watery soft rot (Sclerotinia), crater rot (Rhizoctonia), fusarium rot,
rhizopus soft rot, bacterial soft rot, black rot (Stemphylium), and sour rot
(Geotrichum). Spoilage losses will be minimized if the following precautions
are observed: Use new or disinfested storage containers, handle carefully to
prevent injuries, pre-cool carrots, maintain them at a temperature near 32 F.
and avoid temperature fluctuations.
PACKAGING
Fresh market carrots are washed, sorted, and packed in one or two pound
plastic bags packaged 48 1 lb. bags, or 24 2 lb bags per carton; or loose in
50 pound mesh or plastic sacks at a packing house.
ENTERPRISE BUDGETS
The following information has been quoted form Oregon State University
Extension publication EM 8379, April 1988, which gives costs and return
estimates for carrots grown for processing in western Oregon. The publication
should be consulted for the major assumptions and operations used in con-
structing this information. This budget is intended to be used as a guide in
estimating actual costs and does not represent any particular farm.
Budget: Total variable costs for western Oregon carrots were estimated
at $423.91 and total fixed costs at $225.26 per acre, resulting in $679.17
total cost of production per acre. The break-even price needed to cover
variable costs was $14.13 per ton, and the break-even price needed to cover
all costs was $22.63 per ton, based on an estimated yield of 30 tons per acre.
PEST CONTROL FOR CARROTS
THE PESTICIDES LISTED BELOW, TAKEN FROM THE PACIFIC NORTHWEST PEST
CONTROL HANDBOOKS, ARE FOR INFORMATION ONLY, AND ARE REVISED ONLY ANNUALLY.
BECAUSE OF CONSTANTLY CHANGING LABELS, LAWS, AND REGULATIONS, OREGON STATE
UNIVERSITY CAN ASSUME NO LIABILITY FOR THE CONSEQUENCES OF USE OF CHEMICALS
SUGGESTED HERE. IN ALL CASES, READ AND FOLLOW THE DIRECTIONS AND PRECAUTION-
ARY STATEMENTS ON THE SPECIFIC PESTICIDE PRODUCT LABEL.
USE PESTICIDES SAFELY!
Wear protective clothing and safety devices as recommended on the label.
Bathe or shower after each use.
Read the pesticide label--even if you've used the pesticide before. Follow
closely the instructions on the label (and any other directions you have).
Be cautious when you apply pesticides. Know your legal responsibility as a
pesticide applicator. You may be liable for injury or damage resulting from
pesticide use.
WEED CONTROL
Cultivate as often as necessary when weeds are small. Proper cultiva-
tion, field selection and rotations can reduce or eliminate the need for
chemical weed control.
THE WEED TREATMENTS LISTED BELOW ARE TAKEN FROM THE PACIFIC NORTHWEST
WEED CONTROL HANDBOOK, AND ARE FOR INFORMATION ONLY. CONSULT PRODUCT LABELS
FOR CURRENTLY LEGAL REGISTRATIONS, RATES, AND COMPLETE INSTRUCTIONS.
WEED MANAGEMENT GENERAL STRATEGY
Carrots suppress weeds when row spacings, population densities, cultivation,
and application of a single herbicide are combined. Cultivation also prevents
sunburned or green carrot roots by throwing soilover the roots.
______________________________________________________________________________
STALE SEEDBEDS FOR VEGETABLE PRODUCTION
Stale seedbeds are sometimes used for vegetable production when other selec-
tive weed control practices are limited or unavailable. The concept depends
on controlling the first flush of emerged weeds before planting or emergence
of the crop followed by minimal soil disturbance which reduces subsequent weed
flushes during establishment of the crop. Following establishment, other weed
control practices including cultivation or use of other herbicides can be
used.
1. Prepare a seedbed, preferably 2 to 3 weeks before planting to achieve
maximum weed seed germination near the soil surface. Soil temperatures
and moisture must be reasonable or results will be erratic.
2. Plant the crop with minimum soil disturbance. Otherwise, new weed seed
will be exposed to favorable germinating conditions.
3. Just before or after planting but before crop emergence, treat the
field by flaming or with herbicide to kill all germinated or exposed
weeds.
Weed Treatment Active Ingredient Per Acre and Application Comments
------------------------------------------------------------------------------
Flaming
Use liquid propane or similar fuel-burning equipment to quickly sear the
weeds, but not consume them with flame.
------------------------------------------------------------------------
paraquat 0.625 to 0.94 lb ai/A
Gramoxone Extra
Restricted-use pesticide. Do not ingest or inhale spray mist. Wearing
protective face shields, respirators, and clothing is advised. Apply
during or after planting, but before crop emergence. Add a non-ionic
surfactant or crop oil concentrate according to label specifications,
taking care to avoid anionic formulations that react in the tank to form
insoluble precipitates. Exposed crop plants will be killed. Do not
apply preplant or preemergence to soils lacking clay minerals, such as
peat, muck, pure sand, or artificial planting media. (Acts as contact;
absorbs energy produced by photosynthesis forming peroxides that disrupt
living cells.)
------------------------------------------------------------------------
glyphosate Consult Labels
Roundup
Roundup RT
(E. Washington and
Idaho only)
or Honcho +
nonionic surfactant
Apply to actively growing weeds either preplant in conjunction with site
preparation or preemergence crops listed on the label. Consult label
for specific rates, times of application, and perennial species control-
led. Generally 1 to 1.5 lbs ai/A should be used for annual weeds, while
perennial weeds require higher rates. Addition of a surfactant or
ammonium sulfate improves activity when weeds are stressed. Do not
apply more than 8 lbs. ai/A per year, nor plant non-labeled crops within
12 months following application. (Inhibits production of 3 amino
acids and protein synthesis.)
-----------------------------------------------------------------------
metham sodium 79.5 to 318 lb ai/A
(several brands)
Wearing protective face shields, respirators, and clothing is advised.
Metham sodium is dissolved in water for application, but activity
depends on several soil factors that enhance conversion and movement
from the liquid to gas phase. Cultivate the soil 7 to 10 in. deep
before preparing a uniform seedbed using equipment that leaves a smooth
surface. Soil moisture must be adequate forseed germination, but below
field capacity. Apply when temperatures exceed 50 degrees F with a boom
mounted on the front of a rototiller. Incorporate 3 to 4 in. deep and
seal surface of soil with a smooth roller, power-driven to travel at
same speed as tractor. Soil surface must be smooth without cracks where
fumigant may escape.
Planting may be delayed until soil is free of metham, usually 14 to 21
days. Plant radish seeds or transplant radish seedlings while pro-
tecting from wind and bright sun. Observe for 12 to 24 hours for
wilting. Before planting, till the soil surface (3 to 4 in.) while
breaking the compacted layer formed during incorporation of metham using
a small shank with the seed row. Avoid mixing soil from beneath the
treated layer. Do not contaminate water, runoff water, or fish habitat.
(Disrupts cellmembranes.)
______________________________________________________________________________
PREPLANT INCORPORATED
Weed Treatment Active Ingredient Per Acre and Application Comments
-----------------------------------------------------------------------------
trifluralin 0.5 to 1.0 lb ai/A
Treflan
Apply from 3 weeks to immediately before planting and incorporate 2 to 3
inches deep within 24 hours by cross-disking or using a PTO rotary ti-
ller. Spray only once and avoid overlaps. Consult label for restric-
tions on planting sensitive crops within 12 months. (Inhibits mitosis,
primarily in shoots).
______________________________________________________________________________
POSTEMERGENCE
Weed Treatment Active Ingredient Per Acre and Application Comments
------------------------------------------------------------------------------
linuron 0.75 to 1.5 lb ai/A
Lorox
Apply postemergence when carrots are 3 to 6 inches tall, when grass
weeds do not exceed 2 inches tall, and when broadleaf weeds do not
exceed 6 inches tall. Do not exceed 40 psi spray pressure. Poor weed
control may result when maximum day temperaturesare below 50 F. Injury
may occur if mixed with surfactants, nitrogen, or fertilizer solutions,
or when temperatures exceed 85 F. Applications may be repeated, but do
not exceed 1.5 lb ai/A per season. Do not apply on sand, loamy sands,
gravelly soils, or soils containing less than 1% organic matter. Do not
apply by air. Consult label for planting rotation crops within 12
months. (Inhibits photosynthesis).
------------------------------------------------------------------------
metribuzin 0.25 lb ai/A
Sencor
Apply after carrots have formed 5 to 6 true leaves, but before weeds are
1 inch in height or diameter. Earlier applications will result in
excessive crop injury. If needed, repeat application after at least 3
weeks, but do not apply over 0.5 lb ai/A per year. Do not apply within
60 days of harvest or within 3 days of any other chemical. Do not
apply within 3 days after periods of cool, wet, or cloudy weather, or on
very hot days. Some temporary chlorosis and burning of the leaf tissue
may occur. For carrots with unknown tolerance, treat only a small area
to determine crop safety. (Inhibits photosynthesis.)
-----------------------------------------------------------------------
fluazifop Consult Label
Fusilade 2000
Identify grasses and adjust rates depending on susceptibility and stage
of weed growth according to label instructions. Apply to actively
growing grasses as a directed spray with 1% crop oil or 0.25% nonionic
surfactant. Erratic results often occur when grasses are stressed from
lack of vigor, drought, high temperature, or low fertility. More mature
grasses and quackgrass can be controlled but may require two applica-
tions. Annual bluegrass and all fine fescues resist treatment. Do not
harvest within 45 days of treatment. Grazing is prohibited. (Inhibits
fatty acid production, cell membranes, and new growth.)
______________________________________________________________________________
______________________________________________________________________________
INSECT CONTROL
Proper rotations and field selection can minimize problems with insects.
THE PESTICIDES LISTED BELOW ARE TAKEN FROM THE PACIFIC NORTHWEST INSECT
CONTROL HANDBOOK, AND ARE FOR INFORMATION ONLY. CONSULT PRODUCT LABELS FOR
CURRENTLY LEGAL REGISTRATIONS, RATES AND COMPLETE INSTRUCTIONS.
Insect and Description Control, Active Ingredient Per Acre
---------------------------------------------------------------------------
Aphids, including the Phosdrin - 0.125 to 0.25 lb
"Carrot aphid"
Cavariella aegopodii malathion - 1 to 1.5 lb
Generally yellow in color. diazinon - 0.5 lb
Winged forms marked with
black. Willow is primary host. endosulfan - 0.5 to 1 lb
Summer hosts include carrots. Do not feed tops.
Considered a vector of certain
virus diseases. Pyrellin - 1 to 2 pt
---------------------------------------------------------------------------
Carrot rust fly diazanon - 2 lb
Psila rosae
Mature larvae are dusty, straw-colored,
maggotlike, and from l/8 to 1/4 inch long.
Worms burrow into and through roots.
Burrows are often filled with rust-red frass.
---------------------------------------------------------------------------
Cutworms trichlorfon - 0.5 to 1.0 lb
Many species
carbaryl - 2 lb bait
Small to large larvae that feed
on roots and foliage. Lannate - 0.45 to 0.9 lb
Asana - 0.03 to 0.05 lb
---------------------------------------------------------------------------
Garden symphylan diazinon - 10 lb
Scutigerella immaculata
Telone II - preplant
NOTE: Carrots planted in fields
treated with Dyfonate the previous Telone C-17 - preplant
year have shown damage or excess residues.
---------------------------------------------------------------------------
Wireworms diazinon - 4 lb
NOTE: Carrots planted in fields treated Telone II - preplant
with Dyfonate the previous year have
shown damage or excess residues. Telone C-17 - preplant
---------------------------------------------------------------------------
Six-spotted leafhopper Phosdrin - 0.25 to 0.5 lb
Macrosteles fascifrons
malathion - 1 to 1.5 lb
Grayish green leafhopper about
1/4 inch long. Six black spots on carbaryl - 1 to 1.5 lb
top of head. Transmits aster
yellows (carrot yellows). methoxychlor - 1 to 2.25 lb
Lannate - 0.45 to 0.9 lb
Asana - 0.03 to 0.05 lb
---------------------------------------------------------------------------
Slugs metaldehyde baits
---------------------------------------------------------------------------
---------------------------------------------------------------------------
DISEASE CONTROL
Proper rotations, field selection, sanitation, spacings, fertilizer and
irrigation practices can reduce the risk of many diseases. Fields can be
tested for presence of harmful nematodes. Using seed from reputable seed
sources reduces risk from seed born diseases.
THE PESTICIDES LISTED BELOW ARE TAKEN FROM THE PACIFIC NORTHWEST DISEASE
CONTROL HANDBOOK, AND ARE FOR INFORMATION ONLY. CONSULT PRODUCT LABELS FOR
CURRENTLY LEGAL REGISTRATIONS, RATES AND COMPLETE INSTRUCTIONS.
CARROT -- ASTER YELLOWS
Cause: A mycoplasm like disease that is spread by a leafhopper. The
mycoplasm-like survives through the winter on wild weed hosts. Aster yellows
also occurs in lettuce, endive, tomatoes, parsley, onion, salsify, many weeds,
and several ornamental flowering plants.
Symptoms: New leaves in the heart of the plant are yellow, reduced in size,
deformed, and dense in growth. Older leaves may have a purple or reddish
color. The carrot roots are frequently deformed and develop dense clumps of
rootlets, tufts, or hairlike rootlets. Dormant buds in the crown may develop
so the plant takes on a witches' broom appearance.
~Control:
1. Remove infected plants as soon as detected.
2. Partial control of the leafhopper vector has reduced disease in some
areas. For details of materials and application rates see the Pacific North-
west Insect Control Handbook.
---------------------------------------------------------------------------
CARROT -- BACTERIAL BLIGHT
Cause: Xanthomonas carotae, a bacterium. The disease can be damaging
particularly to carrot seed crop. The pathogen can be seed-transmitted.
Disease development is favored by warm, wet conditions. The pathogen is
spread through rain, splashing irrigation water, or mechanically by insects.
Symptoms: Leaf symptoms start as small, irregular, yellow areas which later
turn to irregular, water-soaked, brown spots. The lesion is surrounded by an
irregular yellow halo and the center becomes dry and brittle. Linear, dark
brown lesions on petioles and stems may appear, sometimes with gummy bacterial
exudate. Partial or complete blighting of umbels may result. Seed yield and
quality may be adversely affected.
~Control: Plant healthy seed. Seed treatment with hot water at 122 oF for 30
minutes is effective. A 2 to 3 year crop rotation and plowing down carrot
refuse are recommended.
---------------------------------------------------------------------------
CARROT -- CAVITY SPOT
Cause: Pythium violae P. ultimum, fungi that live in organic matter in the
soil.
Symptoms: Dark-brown to black lesions, centered on tentacles that are
elongate and relatively shallow. They are usually more numerous on the upper
portion of the carrot.
~Control:
1. Avoid growing carrots on field with a recent history of cavity spot.
2. Plant carrots on most well-drained soils available.
3. Avoid situations where water is allowed to stand between carrot rows.
4. Harvest carrots as soon as they are mature. Avoid storage of roots in the
field.
---------------------------------------------------------------------------
CARROT -- COTTONY SOFT ROT
Cause: Ssclerotinia sclerotiorum, a fungus. The disease is sometimes severe
on stored carrots. The fungus overwinters as sclerotia in the soil.
Other host plants include lettuce, beans, parsnips, cabbage and other
crucifers, and cucurbits.
Symptoms: Cottony white mycelium on surface of soft lesions on the root.
~Control: In the field: Crop rotation. Grow nonsusceptible crops--onions,
grasses, cereals--for 2 years before planting susceptible crops--beans,
lettuce, parsnips, crucifers, celery.
In storage: When not in use, keep containers outside in a dry place exposed to
the sun.
Storage temperature should be near freezing, humidity near 85 percent.
Store carrots in crates to allow air circulation.
---------------------------------------------------------------------------
CARROT -- DAMPING-OFF
Cause: Rhizoctonia sp. and Pythium sp., fungus organisms. These soil-infesting
fungi are widespread and attack young and germinating seedlings of many
plants.
Symptoms: Seedlings that are attacked at the ground level develop a water-
soaked, discolored stem and topple over. Infected plants seldom recover.
~Control: (1) Treat the seed with captan or Thiram 4 oz actual/100 lb of seed.
(2) Plant carrots in well-drained situations. (3) Cultivate the soil surface
lightly and do not overwater. (4) See Damping-Off in Vegetable Seedlings. (5)
The use of 2-year-old seed may reduce disease. Where Pythium is a problem, 4
to 8 pt/a of Ridomil 2E may be preplant incorporated or applied as a band
after planting. Where Pythium is a problem, use Anchor flowable at 1.5 fl
oz/cwt of seed.
Residues: Thiram--4 oz actual/100 lb seed (dry or slurry). Considered to be a
nonfood use.
Captan 4.5 oz (slurry) or 6.75 oz ai (dry)/100 lb of seed. Considered to be a
nonfood use.
---------------------------------------------------------------------------
CARROT -- LEAF SPOT AND LEAF BLIGHT
Cause: Alternaria sp. and Cercospora sp., fungi. The fungi overwinter in the
crop refuse or on alternate hosts.
Symptoms: The disease usually appears first in early fall, but when large
amounts of infested refuse are present, spring infection can occur. Gray to
dark-brown centered spots appear, varying in shape from irregularly round to
elongated. Coalescence of spots with subsequent curling of the leaves is
common. Spots may girdle the petiole and kill the leaf. Leaf spots are common
in carrots grown for seed production in western Idaho and eastern Oregon. Any
of the following do a good job of control: Seed to seed crops--one application
in the fall one, sometimes two, in the spring steckling production--one
application in the fall, one to two applications after transplant in the
spring.
~Control: Irrigation such that carrots are dry at nightfall, combined with
rotation and sanitation should be sufficient to keep the disease under control
however, where the disease occurs commonly, spraying may be necessary. It is
particularly important that you rotate a field out of carrots for at least 1
year since refuse is the main way the organisms overwinter. The following
materials are suggested: Bordeaux 6-6-100, fixed coppers, chlorothalinil l.l3
to l.5 lb. ai/A, Super-Tin, or Du-Ter 1.9 to 3.2 oz ai in 25 to 100 gal
water/A.
When only alternaria is a problem, spray 1-2 lb/A of Rovral in a minimum of 10
gal. of water/A at 7-14 day intervals. Check label for rotation of crop
restrictions.
Residues: Coppers--exempt.
Rovral -- do not apply more than 8 times per season.
Chlorothalinil. No time limitation.
---------------------------------------------------------------------------
CARROT -- MOTLEY DWARF
Cause: Complex of two viruses, carrot mottle virus and carrot red leaf virus.
The disease has occurred in many plantings. Wild carrot is reported to be a
natural host for the viruses. The viruses are carried by the willow aphid
Cavariella aegopodii and not by leafhoppers.
Symptoms: Symptoms on the tops are similar to those of the aster yellows
disease--central rosette, severe stunting and deformation, yellowish and
reddish margins of the leaves. There is no malformation of the roots as there
is in carrots infected by aster yellows.
~Control: Apply insecticides to control the aphid. Refer to the Pacific
Northwest Insect Control Handbook. Avoid late plantings when aphid populations
are high.
---------------------------------------------------------------------------
CARROT -- NEMATODE (Root-Knot)
Cause: Meloidogyne hapla. A nematode which also attacks other vegetable
crops.
Symptoms: Localized areas of stunted plants. Numerous knots can be found on
the tap root and secondary roots. Some growers believe this pest may be one of
the causes of splitting in carrots. When carrots are left in the soil for long
periods in the fall and winter, nematodes often enter lenticel areas and cause
large galls.
~Control:
1. Crop selection. If a grower is determined to grow in an infested field
without soil fumigation, such vegetables as lettuce and onions should be used.
Plant only those crops on which the galls do not appear on the salable portion
of the plant.
2. Rotation. Corn is an excellent alternate since it is rarely injured by
this nematode.
3. Fumigate soil with Telone II.
Residues:
Telone II--preplanting soil fumigation. Allow 2 to 3 weeks to lapse between
time of application and planting or until odor has left soil. Do not treat
extremely heavy soils. Considered to be a nonfood use.
Sampling: Root-knot nematodes are sedentary endoparasites (see Nematodes Life
Histroy) and only second-stage juveniles (the infective stage) and adult males
(which may be rare) are present in the soil. Before planting crops suscepti-
ble to root-knot nematodes, soil samples should be taken with sufficient lead
time to implement management procedures if necessary. For example, after soil
fumigation, it may be several weeks before crops can be planted. Fall
sampling for crops to be planted the following spring is an excellent strate-
gy. Northern root-knot nematodes are very damaging to carrot, and the
tolerance is very low, so proper nematode sampling is essential. When sending
samples for diagnosis, it is best to include carrots and roots as well as
soil.
Reference: See Soil Fumigants.
---------------------------------------------------------------------------
CARROT -- POWDERY MILDEW
Cause: Erysiphe sp., a fungus. This fungus can be found on fall planted
carrots, and it overwinters on the carrot seed crop. Another host plant is
wild carrot. Some varieties, like `Nantes' and `Imperator', appear to be more
susceptible to the disease.
Symptoms: The disease affects the foliage, stems, and umbels. Patches of the
white feltlike fungus appear on the lower leaves first, then spread to the
terminal growth. The fungus often covers entire leaves with its masses of
white mycelium and powdery spores. Infected foliage becomes brittle and may
eventually turn brown, shrivel, and die. Diseased pedicels may turn brown
resulting in the premature death of the florets. Severe infection results in
low yields and poor seed quality.
~Control: Isolate new carrot fields from established fields infected with
mildew. Presently no materials are registered for the control of this organism
on carrot.
---------------------------------------------------------------------------
CARROT -- SEED TREATMENT
Aids in controlling damping-off and seed decay:
Thiram 0.5 tsp/lb of seed. Do not apply more than 4 oz ai/100 lb of seed (dry
or slurry). Considered to be a nonfood use. The use of 2-year-old seed also
reduces diseases.
Anchor 1.5 oz/ct seed.
---------------------------------------------------------------------------
CARROT -- SOFT ROT
Cause: Erwinia carotovora, a bacterium. The causal bacteria live over in
decaying refuse and enter the root principally through cultivation wounds,
harvest bruises, freezing injury, and insect openings. Following infection
high humidity is essential for progress of the disease.
Symptoms: Carrots, parsnips, potatoes, onion bulbs, and celery are only a few
of the many plants attacked. A soft decay of the fleshy root tissues occurs
and takes on a watery or slimy consistency as the rot progresses. Rotted
tissues keep their natural color until they are completely decayed. In the
field, the tops of rotted carrots turn yellow and wilt as the roots break
down.
~Control: When soft rot occurs in the field, there is no known control. (1)
Use care in handling crop at harvest avoid bruising and other injuries. (2)
Allow crops to dry thoroughly with adequate aeration before storing. (3)
Disinfect storage with a spray using 1 to 2 lb of copper sulfate to 10 gal of
water. Store at temperature just about 30 F and 85 to 90 percent relative
humidity.
---------------------------------------------------------------------------
CARROT -- VIOLET ROOT ROT
Cause: Rhizoctonia crocorum, a soilborne fungus. In the Pacific Northwest the
disease has been a problem in some carrot plantings. The fungus is known to
occur in several countries of the northern hemisphere and is reported to have
a wide host range--asparagus, artichoke, alfalfa, bean, beet, cabbage, celery,
clover, dandelion, fennel, mangel, parsley, potato, rape, rhubarb, sugar beet,
sweet potato, and turnip.
The fungus may be spread as a contaminant on seed, plant parts, soil, tools,
flood water, and equipment.
The fungus remains alive in the soil for at least 1 year. The mycelium grows
through the soil from plant to plant. Optimum temperature for infection is 59
to 61 F. The disease is most destructive on heavy unlimed soils.
Symptoms: The disease attacks the underground parts of the plants causing
stunting, yellowing, wilting of the above ground parts, or death of the plant.
The fungus produces a loose mat of reddish-purple mycelium over the under-
ground portions of the plant. Embedded in the mat are numerous small dark
sclerotia. A dry rot occurs which may be followed by a wet rot caused by
secondary organisms.
~Control:
1. Use long rotations (4 to 5 years)--include cereals and grasses.
2. Provide good weed control and drainage.
3. Maintain good fertility, proper liming.
___________________________________________________________________________
___________________________________________________________________________
---------------------------------------------------
---------------------------------------------------
This information was adapted by the Oregon State
University Extension Service from Oregon and
Pacific NW publications as well as other vegetable
production guidelines from public institutions
in the U.S. and Canada. These guidelines are
intended as a general guide for Oregon commercial
vegetable producers. Address comments or questions
to your County Extension Agent or Dr. N. S.
Mansour, Department of Horticulture, Oregon State
University, Corvallis, OR 9733l.
---------------------------------------------------
---------------------------------------------------