From: Brian Lo <dragon@csulb.edu>
Newsgroups: rec.gardens
Subject: FAQ: Tomatoes
Date: Wed, 1 Mar 1995 09:07:39 -0800
TOMATOES
Lycopersicon esculentum
Tomatoes, tree tomatoes (also call tamarillos), tomatillos and husk
tomatoes (also called ground cherries) are all in the Solanaceae family.
The tomatillo and related husk tomatoes belong to a different taxonomic
genus (Physalis ixocarpa) and differ from tomatoes in that their fruit is
encased in a thin husk which is removed when the fruit is used. Tomatillos
produce large branched plants. Tomatillos are picked when the fruit has
reached full size and is still green. The fruit is often mixed with hot
peppers and other ingredients to make green salsa. Varieties of Tomatillo
are: Tomatillo Green (used in "salsa"); also Tomatillo Purple (purple fruit);
Rendidor (commonly used in Mexico).
The husk tomato or ground cherry fruit is much smaller than the toma-
tillo, is very sweet and used mainly for jam and preserves after the fruit has
ripened and turned yellow. Varieties of husk tomato are: Husk Tomato Goldie,
Husk Tomato Strawberry.
The tree tomato belongs to still another genus, Cyphomandra betacea, and
is a tropical plant not suited for out-door production in the Pacific North-
west. Its fruit, promoted by New Zealand, is marketed in the U.S.A. under the
trade name Tamarillo. The fruit resembles a small eggplant more than a
tomato, may be red or yellow, is bland or semi-sweet. Tree tomato plants are
a small perennial bush or shrub 6 to 10 feet tall, frost sensitive, and bear
after the second year.
TOMATO VARIETIES
Tomato varieties mature over a wide range, commonly from 75 days for
early cherry types to 85 days for early full size fruit types, 100 days for
medium, and 110 days for later, full season varieties from direct seeded
plantings. Transplanted plantings would be about 25 days less.
In the arid, irrigated areas east of the Cascades tomato production may
be severely limited by curly top virus. Commercial production is limited to
the use of varieties with resistance. Resistant varieties have been developed
and released by Dr. Mark Martin through the A.R.S., U.S.D.A. curly top
breeding program at the Irrigated Agriculture Research and Extension Center,
Prosser WA. These varieties are all red-fruited: Columbian, Rowpac, Roza,
Saladmaster, released in the 1960s for fresh market, and a "CVF" series
released in the 1980s for processing and market. Limited quantities of seed
and descriptions of these varieties is available from:
Dr. Erik Sorensen, WSU Cooperative Extension, Courthouse,
Pasco WA 99301, phone: 509/545-3511
Dr. Dennis Johnson, WSU, Rt. 2, Box 2953-A,
Prosser WA 99350-9687, phone 509/786-2226
Mr. Gary Pelter, WSU Cooperative Extension, Courthouse,
Ephrata, WA 9882, phone 509/754-2011 ext.412
Standard tomato varieties, red:
Bush types: Early to mid season - Santiam, Oregon Spring, Oregon Star,
Oregon Pride (all seedless, with the latter two being large-fruited, resem-
bling paste tomatoes), Springset, New Yorker, Fireball, Earlirouge, Earli-
bright, Coldset, Jetfire, Willamette, Pilgrim (early with multiple disease
resistance).
Bush types: Mid Season to Late - Pik Red, Celebrity, Pik Rite, Castlehy
101, Carnival, All Star, Setmore, Supersonic, Royal Flush, Monte Carlo,
Better Boy, Carmen, Medford, Milagro, Sunny, Summerset. Research in the
Hermiston area indicates that Baja, Keno, Oregon Spring and Valerie performed
well.
For trial: Spectrum 882 (solid, multi-purpose, medium to large oval
fruit); Merced (tolerant to gray wall), Solar Set (reported high temperature
tolerance but susceptible to gray wall), Colonial (jointless stem, green
shoulder, large); Sunrise (VFF,Alt,TMV); Daybreak (VFF,Asc,St); Big Beef (All
America, medium-early beefsteak, VFF,Alt,St,N,TMV).
Staking: Early Girl, Fantastic, Keno.
Cherry type, red,indeterminate: Sweet l00, Large German Cherry.
Cherry type, red, determinate: Small Fry, Presto, Sweetie, Cerry Grande.
Processing (paste) tomatoes: Bellstar, Chico III, Murrieta, Reliant,
Nova, RomaVF, Hybrid 882, La Rossa, Milano, Heinz 2653, Vega (VFF).
Yellow: Yellow, large fruited types: Orange Queen, Jubilee, Lemon Boy,
Golden Boy.
Yellow cherry type, determinate: Gold Nugget.
Yellow cherry type, indeterminate: Yellow Plum.
Yellow and red striped: Tigerella, Tigerette.
Novelty: White - Great White (beefsteak type), White Beauty. Pink -
Pink Girl, Ponderosa Pink (beefsteak type), Mac Pink. Pink Grapefruit (a
yellow-skin fruit with pink flesh). Yellow and red stuffing: Yellow Stuffer,
a pepper-like tomato, hollow, for stuffing. Liberty Bell, a red pepper-like,
hollow fruit used for stuffing.
Greenhouse: See separate file on greenhouse tomato production.
SEED COMPANIES
Asgrow Seed Company, POB 5038, Salinas CA 93915
R.S. de Ruiter Seeds Inc. 3001 Bethel Rd. Suite 207, POB 20228, Columbus, OH
43220 ph: 614/459 1498
Ferry-Morse Seed Co. POB 4938, 555 Codoni Ave. Modesto, CA 95352
Harris Moran Seed Co. 3670 Buffalo Rd. Rochester, NY 14624
La Marche Seeds International, POB 190, Dixon, CA 95620
Nichol's Garden Nursery, 1190 North Pacific Highway, Albany, OR 97321
Nunhems Seeds Corp. POB 18, Lewisville, ID 83431 ph: 208/754-8666
Petoseed Co. Inc. POB 4206, Saticoy, CA 93303
Rogers NK. POB 4727, Boise ID 83711 ph: 208/322-7272
Stokes Seeds Inc. POB 548, Buffalo, NY 14240 ph: 416/688-4300
Thompson and Morgan. POB 1308 Jackson, NJ 08527 ph: 201/363-2225
Vilmorin Inc. 6104 Yorkshire Ter. Bethesda MD 20814 ph: 301/564-6246
W. Osborne Seed Co. Int'l. 1679 Highway 99 South, Mount Vernon, WA 98273
SEED AND SEED TREATMENT
Tomato seed numbers approximately 11,500 per ounce. Most of the new
hybrids are sold by seed number. Use only treated seed from a reliable seed
source. Some seed companies now can furnish tomato seed that has been
"vigorized" or "conditioned" to allow germination under adverse (cool)
temperature conditions.
Research in Indiana has demonstrated a benefit from pop-up fertilizers.
In direct seeded plantings, spray directly on the seed a solution of 2-6-0
(made up of 1 part 10-34-0 : 4 part water) at 1 pint per 100 lineal feet of
row (use 1/2 this rate on sandy soils).
TRANSPLANT PRODUCTION
Use l or more oz. of seed per acre, depending on the variety and
required plant population. Sow them in the greenhouse 6 to 8 weeks before
field transplanting. Seedlings are transplanted to other flats when the first
true leaf has formed. Veneer bands or jiffy pots may be used to advantage.
Space between the plants should be 2 to 2 l/2 in. Provide adequate ventila-
tion during the heat of the day, particularly after watering, which should be
completed before l p.m. Water plants before signs of wilting appear.
Tomato is a warm-temperature vegetable and requires a long growing
season. Transplants should be kept close to the following temperatures: 64
to 70 F during the day, 55 to 61 F at night until the seedlings are thinned
out.
When the first true leaf has formed, early flowering can be increased by
a one-week cold treatment at 54 F. Caution: Do not subject transplants with
4-5 true leaves to cold temperatures (around 50 F. nights and 60-65 F. days)
for more than a week since this will increase catfaced fruit.
TRANSPLANTING
Condition transplants for 1-2 days before transplanting to the field by
slightly reducing the moisture and maintaining approximate outdoor tempera-
tures. Do not over-harden (see note on catfacing above). Thoroughly water
plants l2 to l4 hours before transplanting to the field. Plants should be dug
or cut loose from the soil when being transplanted; ensure the roots are not
exposed to sun or drying wind.
Apply a starter fertilizer solution to the transplants when transplan-
ting to the field. Select starter fertilizers that have the highest level of
phosphorus available, such as 10-52-17, 11-48-0, 11-55-0 dry fertilizers or
10-34-0 liquid fertilizer. Make up a stock solution of 3 lbs of the dry, such
as 10-52-17, or 2 pints of liquid 10-34-0 per 50 gallons of water. Use 1/2
pint of of this stock solution per plant, applying the solution directly to
the plant roots when setting in the field.
TEMPERATURE
Recent research indicates that a temperature of 68-78 F. is ideal for
optimal growth.
SPACING
Use rows 4-5 ft. apart and space transplants 12 to 48 inches apart in
the row, depending on variety.
Direct seeding should be done with early varieties only. Drop 1-3 seeds
per hill and space 9-12 in. apart in rows spaced 48-60 inches.
Tomatillos are usually grown from transplants planted in rows 5 feet
apart with a 2.5 foot spacing in the row.
WINDBREAKS
Use windbreaks as necessary especially in eastern Oregon. Grain wind-
breaks have been found effective when grain rows are used for each tomato row.
Winter wheat varieties, rye, or oats can be used. Spring barley may be used
for February plantings. Seed grain thickly, 2-3 seeds per inch. This requi-
res about 10 lbs. of barley, 9 lbs. of wheat, or 8 lbs. of rye to seed grain
rows 12 feet apart. Tomatoes and windbreaks should be cultivated after they
are well established.
FERTILIZER
A soil test is the most accurate guide to fertilizer requirements. As a
general guideline before transplanting, broadcast and disc in the following:
Nitrogen: 75-100 (N) lb./acre
Phosphate: 100-150 (P2 O5) lb./acre
Potash: 100-150 (K2 O) lb./acre
Sulfur: 25-30 (S) lb./acre
Side dress with 25-50 lb. of nitrogen per acre when first fruits appear.
Where mulching and trickle irrigation are practiced, additional nitrogen
can be fed through the trickle irrigation system at 15 lb/acre when the first
fruit begins to set and an additional 15 lb/acre four weeks after. To prevent
clogging or plugging from occurring use soluble forms of nitrogen (Urea or
Ammonium nitrate), and chlorinate the system once a month with a l0 to 50 ppm.
chlorine solution. Chlorinate more frequently if the flow rate decreases.
Avoid excessive nitrogen applications which can cause excessive vine
growth and delay maturity.
PLASTIC GROUND MULCHES AND ROW COVERS
The use of black plastic ground mulch is recommended, especially in
Western Oregon. Plastic mulch conserves moisture, increases soil temperatures
and protects fruit from ground rot, enhances earliness and increases yields.
Spunbonded polyester or propylene, and perforated polyethylene row
covers may be used for 4 to 8 weeks immediately after transplanting or direct
seeding. Covers should be removed when plants begin to flower or if tempera-
tures become excessive under the covers. Do not allow temperatures to exceed
90 F for more than two or three consecutive days. Row covers increase heat
unit accumulation by 2 to 3 times over ambient. Two to four degrees of frost
protection may also be obtained at night. Soil temperatures and root growth
are also increased under row covers as are early yields, and in some cases
total yields.
IRRIGATION
Apply water uniformly to reduce incidence of blossom end rot. Irrigate
carefully after fruit ripens to reduce fruit decay and cracking. A total of
12-15 inches may be needed in western Oregon. Approximate summer irrigation
needs for the Hermiston area have been found to be: 3.5 inches in May, 5.0 in
June, 7.5 in July, and 7.0 in August.
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.
CHEMICAL FRUIT RIPENING
Ethrel may be used for uniform ripening for once-over harvest and to
enhance ripening in late varieties, or during late seasons, or when ripening
is delayed. The proper use of Ethrel can advance harvest about 5-7 days.
Apply when fruit is at the mature green stage (when fruit locules contain
jelly). Ethrel is effective only on mature-green fruit. The key to good
results is good coverage. Apply 3.0-4.0 pints Ethrel (2 lbs/gal formulation)
in 40-80 gal. water/acre. Use higher rates when day temperatures are less
than 64 F and tomato growth is dense. Ideal temperature range is 75-85 F. Do
not exceed 6.5 pints total, or excess residues may result. CONSULT PRODUCT
LABEL FOR FULL INSTRUCTIONS AND CAUTIONS. If tomatoes are water stressed,
defoliation may occur. Fruit do not appreciably increase in size after
Ethrel treatment.
Harvest fruit at proper maturity, generally l4 to 2l days after treat-
ment. Observe treated fruit frequently for condition of crop ripening. Cool
temperatures can slow Ethrel absorption and color development and extend
period between treatment and harvest.
NON-PATHOGENIC FRUIT DISORDERS
Blossom-End Rot: Varieties differ in susceptibility. Caused by calcium
imbalance or deficiency during critical stage of fruit differentiation and
expansion, usually induced by eneven watering or water stress.
Gray-Wall: This disorder appears as gray or brown blotchy areas in the
fruit wall tissue, beginning when the fruit is green. It can occur on more
than half of the fruit of a particular field. Cross-sections of fruit show
blackened tissue. This causes the external fruit color to look somewhat gray.
When the fruit ripens, the area remains firm and turns from green to yellow,
rather than red. Fruit thus ripens unevenly. The affected area appears woody
when cut. White wall tissue has been considered to be an early stage of gray
wall, but may also be related to other disorders (see "internal white tissue"
section below). A definite cause for gray wall has not been defined but a
number of factors play a role in predisposing fruit to gray wall, these are
listed in their considered lessening degree of importance:
1. Low light or prolonged cloudy periods.
2. Excess nitrogen causing excessive plant vigor.
3. High soil moisture from excess rain or irrigation.
4. Potassium deficiency.
5. Soil compaction.
6. Temperature fluctuations, particularly unusually cool nights and
warm days.
Tobacco mosaic virus is also reported to be involved in gray wall. In
those cases the disorder is also called internal browning. That tobacco
mosaic virus is involved in a disorder called internal brownig is not in
dispute. What is in dispute is wheather the two disorders are the same or
seperate. In a few other cases certain bacteria and fungi are thought to also
be implicated. Another confusion is that gray wall is also sometimes called
blotchy ripening!
Information from Florida indicates that the varieties Merced and
Floridade may have tolerance to the conditions that predispose tomatoes to
gray wall
Blotchy Ripening (see gray wall).
Internal white tissue: The expression of white tissue varies widely,
and is considered dependent on cultivar and environmental conditions. It is
sometimes attributed to gray wall. Potassium deficiency and high temperatures
are believed to aggravate the problem.
Solar yellowing (also called yellow shoulder, yellow top and persistent
green shoulder): This problem occurs most commonly on fruit ripening in late
May and June when days are longest, sunlight is most intense, and temperatures
exceed 85 F. Under such conditions, lycopene (the red pigment in tomato)
fails to develop normally in some varieties, leaving only the carotene
(yellow) pigment to show at the shoulder or, with green-shoulder type toma-
toes, where the dark green portion was. Even with temperatures under 85 F.
the surface temperature of exposed fruit, especially those with dark green
shoulders can become high enough to inhibit normal red color development. In
other parts of the day or night, when temperatures do not exceed 85 F. some
red color may develop, resulting in an orange rather than a yellow abnormali-
ty. To reduce this problem, choose uniform-ripening varieties and protect
fruit surfaces from short-wave solar radiation by choosing varieties having
good fruit cover or, by the use of non-phytotoxic white wash applied when
fruit are at the mature-green stage. The white wash will have to be removed
before the fruit is marketed.
Sunscald; Mature green and tomatoes just turning red are most suscept-
ible. Fruit develops white necrotic tissue surrounded by a yellow halo. The
area may be sunken and wrinkled. Damage is confined mainly to the upper
portion of the fruit, and is seen where fruit that has been covered by leaves
is suddenly exposed to light. The area can later be covered by a black fungus
when the rest of the fruit turns red.
Roughness and scars: Varieties differ in susceptibility. associated
with large fruit. Particularly severe when young plants are exposed to cool
temperatures, and night temperatures below 50 F. when flower clusters are
differentiating.
Fruit cracks: Varieties differ in susceptibility. Promoted by fluctua-
tions in soil moisture and temperature. Often seen when varieties developed
for hot, arid climates are subjected to humid, wet conditions. Cracks may be
radial or concentric.
HARVESTING, HANDLING AND STORAGE
Tomato yields vary with area and number of harvests. Yields may range
from 230 to 270 cwt./acre, or about 1200 20 lb. boxes per acre.
Tomatoes may be harvested at the mature green stage (when the fruit
cavity is filled by gel), semi-ripe (with different amounts of red pigmenta-
tion) or fully ripe, depending or marketing requirement. They are very
perishable and subject to surface and internal damage, and must be handled
accordingly. Tomatoes are sensitive to chilling injury which differs with
maturity of the fruit. Proper temperature management for ripening and storage
are critical to maintain quality.
STORAGE (quoted form USDA Ag. Handbook # 66):
Store mature-green tomatoes at 55 to 70 F; ripe fruit at 45 to 50 F and
a relative humidity of 90 to 95%.
Mature-green tomatoes cannot be successfully stored at temperatures that
greatly delay ripening. Tomatoes held for 2 weeks or longer at 55 F may
develop abnormal amount of decay and may fail to develop a deep red color.
The optimum temperatures for ripening mature-green tomatoes range from 65 to
70 F. Tomatoes will not ripen normally at temperatures above 80 F. A
temperature range of 57 to 61 f is probably most desirable for slowing
ripening without increasing decay problems. At these temperatures the more
mature fruit within the mature-green range will ripen enough to be packaged
for retailing in 7 to 14 days.
Fruit held below 50 F become susceptible to alternaria decay during
subsequent ripening. Increased decay during ripening occurs after 6 days'
exposure at 32 or 9 days at 40 F. Mature-green tomatoes may also be damaged
by low temperatures in the field. A high percentage of tomatoes exposed to
temperatures below 50 F for a week before harvest would probably develop
alternaria rot even at recommended storage temperatures. Some loss due to
chilling can be expected in fall-grown tomatoes exposed for over 95 hours to
temperatures below 60 F during the week before harvest. Severity of chilling
increases with increases in exposure time, so 135 hours' exposure to below 60
F may result in heavy losses.
Chilling periods for fruit while in the field, during transit, and in
storage have a cumulative effect. Thus, fruit chilled for only a short period
in the field can become very susceptible to decay when held for only a short
period at chilling temperature during transit or storage. Tomatoes should be
kept out of cold, wet rooms because in addition to potential development of
chilling injury, extended refrigeration damages the ability of fruit to
develop desirable fresh tomato flavor.
Ripening of tomatoes is initiated by the ethylene they produce. How-
ever, in commercial practice, mature-green tomatoes are commonly treated with
supplemental ethylene to hasten ripening within a lot. For treatment,
tomatoes are exposed to 100 to 150 ppm ethylene for 24 to 48 hours at 68 to 77
F and 85 to 95% relative humidity. Ethylene is applied in a fairly airtight
room by a shot method, a generator, or a flow-through system. Immature
tomatoes may ripen with supplemental ethylene, but the ripened fruit will lack
quality. Fruit beyond the breaker stage do not benefit from supplemental
ethylene because their ripening processes already have been initiated by their
own ethylene.
Semi-ripe tomatoes with 60 to 90% color can be held up to a week at 50
F. If held longer, they will probably not have a normal shelf life during
retailing. Riper tomatoes will tolerate lower temperatures. For example,
"firm-rip" tomatoes can be held a few days at 45 to 50. Long holding of
ripened tomatoes at low temperatures (40 and below) results in loss of color,
shelf life, and firmness.
Fully ripe: When it is necessary to hold fully ripe tomatoes for the
longest possible time before their immediate consumption upon removal from
storage, as for example, for ship-board or overseas use, they can be held at
32 to 35 F for up to 3 weeks. Such tomatoes, although acceptable, would not
be of high quality and would have little if any shelf life remaining. Mature-
green, turning, or pink tomatoes should be ripened before storing at such low
temperatures.
A storage temperature of 50 to 55 F is recommended for semi-ripe to
fully ripe greenhouse-grown tomatoes. Ripening of less mature tomatoes at 70
F is recommended before storage at 50 to 55 F.
Research showed that an atmosphere with 3% oxygen and 97% nitrogen
extended the life of mature-green tomatoes up to 6 weeks at 55 F and that the
flavor of the ripened fruit had no off-flavor and was acceptable to the taste
panel. A 1% or lower oxygen level can cause off-flavor. Increased carbon
dioxide levels provide no benefit; in fact, levels of 3 to 5% have been
reported to cause injury at 55 F.
PACKAGING
Cherry tomatoes are commonly packaged in 8 lb. baskets.
Mature green tomatoes are commonly packaged in 30 lb. cartons and
wirebound crates, volume fill pack.
Pink and ripe tomatoes are commonly packaged in 20 lb. two-layer flats
and cartons, tray pack; or 28 lb. three-layer lugs and cartons, tray pack; or,
30 lb. cartons, loose pack.
PEST CONTROL FOR TOMATOES
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
When black plastic ground mulch is not used, cultivate as often as
necessary when weeds are small. Proper cultivation, 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.
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
(see remarks)
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 nonionic
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.)
______________________________________________________________________________
PREEMERGENCE SOIL-APPLIED
DIRECT-SEEDED AND TRANSPLANTS
Weed Treatment Active Ingredient Per Acre and Application Comments
------------------------------------------------------------------------------
napropamide 1 to 2 lb ai/A
Devrinol
Apply and incorporate uniformly 1 to 2 inches deep. Use lower rates on
light, sandy, or coarse-textured soils. Following harvest, deep
moldboard plowing or disk plowing must be completed before planting
succeeding crops. (Inhibits roots of seedlings).
------------------------------------------------------------------------
bensulide 4 to 5 lb ai/A
Prefar
Apply before seeding or transplanting and incorporate 1 to 2 inches deep
either simultaneously or immediately by cross-disking or using a PTO
rotary tiller, or apply preemergence to weeds soon after seeding or
transplanting and follow with 1-inch overhead moisture. Sometimes the
first flush of weeds must be controlled with cultivation before herbi-
cide begins to control grass. Consult label for planting sensitive
crops within 18 months. (Inhibits mitosis).
------------------------------------------------------------------------
DCPA 9 lb ai/A
Dacthal
(transplants only)
Apply 4 to 6 weeks after transplanting to weed-free soil. Soil should
be moist and additional water applied for activation. Performs poorly in
western Oregon and Washington. Consult label for planting sensitive
crops within 12 months. Results can be improved with overhead irriga-
tion applied immediately after spraying. (Inhibits mitosis).
______________________________________________________________________________
ACTIVATED CHARCOAL SEED PROTECTION
Several Pacific Northwest grass seed crops are protected from herbicide injury
with the use of activated charcoal which adsorbs and detoxifies or inactivates
the herbicide. In vegetables, activated charcoal can be mixed with horticul-
tural grade vermiculite and applied as an anticrustant/seed protectant. The
activated charcoal vermiculite mix is placed within the seed furrow using a
positive feed device. Herbicides must not leach excessively or move readily
from crop roots into the plant. Although crop safety can be enhanced, weeds
emerging from within the treated area also are protected.
Another use for activated charcoal involves seed protection from herbicides
that leach into the seed zone from excessive rainfall. Seed coatings of
activated charcoal would reduce the active concentration of herbicide at or
very near the seed during the germination process.
Activated charcoal/vermiculite mix: Thoroughly mix 1 lb activated
charcoal/ft3 of number 2 or 3 grade horticultural vermicu-
lite. If severe dustiness is a problem, add a small amount
of water. Apply 1 ft3 of mixture/600 ft. of seeded row or
approximately 15 cu.ft/A. Fill the seed furrow using a
positive feed applicator and press with a press wheel.
------------------------------------------------------------------------------
pebulate 4.0 to 6.0 lb ai/A
Tillam
Apply and immediately incorporate prior to seeding or transplanting, or
at layby, apply as a directed spray and incorporate. Do not apply
within 8 days of harvest. Use the 4 lb. rate on coarse soils and on
soils with less than 10% organic matter. Do not use hot caps on
transplanted tomatoes.
______________________________________________________________________________
POSTEMERGENCE
Weed Treatment Active Ingredient Per Acre and Application Comments
------------------------------------------------------------------------------
metribuzin Broadcast
Lexone, Sencor 0.25 to 0.5 lb ai/A
(established
tomatoes only)
Apply as a single treatment or split application allowing a nimimum of
14 days between treatments at 0.25 to 0.37 lb ai/A to tomatoes with at
least 5 to 6 true leaves, but before weeds are 1 inch tall. Use lower
rates on soils of 0.5 to 2% organic matter, but do not use on soils
containing less than 0.5% organic matter. Do not use surfactant,
tank-mix with other pesticides, apply within 24 hours of other pesticide
applications, nor apply within 7 days of harvest. Do not apply within 3
days after periods of cool, wet, or cloudy weather. Do not exceed 1.0 lb
ai/A per season. Read the label carefully and note other precautions.
(Inhibits photosynthesis).
------------------------------------------------------------------------
Directed spray
0.5 to 1.0 lb ai/A
Apply as a directed spray, either in a single treatment or split
application allowing a minimum of 14 days between treatments when
intense weed pressure exists or in fields with hard to control weeds.
Do not exceed 1.0 lb ai/A per season. Note all other precautions listed
above and on label.
------------------------------------------------------------------------
Sethoxydim 0.29 lb ai/A
Poast
Identify susceptible grasses and apply at optimum growth stage listed on
the label. Add 2 pints/A nonphytotoxic crop oil concentrate to im-
prove leaf absorption. Erratic control often occurs when grasses are
stunted or stressed from drought, high temperatures, or low fertility.
Resistant grasses include annual bluegrass and all fine fescues, whereas
quackgrass can be suppressed. Do not apply within 20 days of harvest,
nor exceed 4.5 pints/A per season. (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 ARE
CURRENTLY LEGAL REGISTRATIONS, RATES AND COMPLETE INSTRUCTIONS.
Insect and Description Control, Active Ingredient Per Acre
---------------------------------------------------------------------------
Aphids, including endosulfan - 0.5 to 1 lb
Green peach aphid
Myzus persicae malathion - 1 to 2 lb
Potato aphid diazinon - 0.25 lb
Macrosiphum euphorbiae
Phosdrin - 0.25 lb
Yellowish, pink to pale green
plant lice. azinphosmethyl - 0.5 to 0.75 lb
methyl parathion - 0.5 to 1.5 lb
Asana - 0.03 to 0.05 lb
dimethoate - 0.25 to 0.5 lb
Lannate - 0.45 to 0.9 lb
Di-Syston - 1 to 3 l
---------------------------------------------------------------------------
Colorado Potato Beetle azinphosmethyl - 0.375 lb
Leptinotarsa decemlineata
Di-Syston - 1 to 3 lb
Yellow and black striped beetle.
Larvae reddish orange with two carbaryl - 1 lb
rows of black spots on each
side. endosulfan - 0.5 to 1.0 lb
phosphamidon - 0.5 to 1.0 lb
methoxychlor - 1 to 3 b
Asana - 0.035 to 0.05 lb.
---------------------------------------------------------------------------
Cutworms, armyworms carbaryl bait - 2.0 lb
Different species
Lannate - 0.45 lb
Small to large larvae that feed
on stems, foliage, and fruit. Asana - 0.03 to 0.05 lb
malathion - 3.5 lb
Armyworm only.
Bacillus thuringiensis -
1 to 2 qt. Use an appropriate
spreader-sticker.
azinphosmethyl - 0.75 to 1.5 lb
---------------------------------------------------------------------------
Flea beetles and Cucumber Beetles Di-Syston - 1 to 3 lb
including Tuber flea beetle, Flea beetle only.
Epitrix tuberis
methoxychlor - 1 to 3 lb
Small, oval, shiny bronze jump-
ing beetles. Feed on foliage. rotenone - .5 lb
and Western spotted cucumber beetle carbaryl - 0.5 to 1 lb
Diabrotica undecimpunctata Flea beetle only. Extremely
hazardous to pollinating bees.
Yellowish-green, black-spot-
ted beetle. Common to western endosulfan - 0.5 to 1 lb
Oregon. Damaging to small Flea beetle only.
plants.
Dibrom - 1 lb
Flea beetle only.
azinphosmethyl - 0.5 to 0.75 lb
Flea beetle only.
Asana - 0.03 to 0.05 lb
methyl paration - 1.0 to 1.5 lb
---------------------------------------------------------------------------
Tomato hornworm Dibrom - 1 lb
Manduca quinquemaculata
endosulfan - 0.5 to 1 lb
Mature caterpillar 4 to 5 inches
long, pale green with a short trichlorfon - 1 lb
curved red horn on posterior
end. azinphosmethyl - 0.75 to 1.5 lb
Asana - 0.015 to 0.03 lb.
carbaryl - 1 to 2 lb. Extremely
hazardous to pollinating bees.
Lannate - 0.45 to 0.9 lb
Bacillus thuringiensis - 1 to 2
qt. Use a spreader sticker to
enhance control.
---------------------------------------------------------------------------
Spider mites methyl parathion - 1.0 to 1.5 lb
Tetranychus spp.
Kelthane MF - 0.375 to 0.75 lb
Tiny, spiderlike animals lo- Do not feed.
cated on undersurfaces of foli-
age. Feed on plant juices and Phosdrin - 0.5 lb
cause leaves to yellow and die.
Dibrom - 1 lb
Di-Syston - 1 to 3 lb
---------------------------------------------------------------------------
Wireworms diazinon - 3 to 4 lb
Limonius spp.
Telone II - preplant
Brown, jointed larvae of click
beetles. Kill young plants, Telone C-17 - preplant
weaken older ones.
___________________________________________________________________________
___________________________________________________________________________
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.
TOMATO - ANTHRACNOSE
Cause: Colletotrichum coccodes, a fungus. The disease is not as common in the
Pacific Northwest; however, it does occur.
The fungus persists from season to season on infected plant refuse in the
soil. The initial fruit infection may come from infected leaves, but most
fruits probably are infected from spores produced in the soil. Fruits may be
infected when green and small, but they show no evident spotting until they
begin to ripen. Fruits become increasingly susceptible as they approach
maturity.
In wet weather, the spores produced in the spots on the fruit are splashed by
rain or are spread by pickers to infect other fruits. Overhead irrigation
favors the spread of disease.
Symptoms:
Fruit: Spotting on the fruit is the major symptom of anthracnose; however,
there may also be leaf infection. At first, infected fruits show small,
slightly sunken, water-soaked, circular spots. These spots soon become about
one-half inch in diameter, darker, and more depressed, and often have concen-
tric markings. The centers sometimes become tan and have numerous dark specks.
In warm weather the spot soon penetrates into the fruit and the fruit becomes
worthless.
Leaves: Each leaf spot is a small, dark area of dead tissue, often surrounded
by a yellow zone. The oldest leaves are the most commonly infected.
~Control:
1. Avoid planting in poorly drained soils. Anthracnose is likely to be more
prevalent in wet soils.
2. Use 3 to 4 year rotation. The fungus lives from season to season in plant
parts in the soil.
3. Spray with Maneb or chlorothalonil (Bravo).
Residues:
Chlorothalonil (Bravo 720) 2 to 3 pt of product/A in sufficient water to
cover. No time limit. Tolerance 5 ppm.
Maneb -- apply at 1.2 to 1.6 lb ai/A. Do not apply more than 6.4 lbe ai/A or
within 5 days of harvest.
---------------------------------------------------------------------------
TOMATO - ASTER YELLOWS
Cause: The aster yellows mycoplasmalike organism which is transmitted by
several leafhoppers.
Symptoms: Plants are yellow and stunted. The youngest leaves show vein
clearing and marginal yellowing. The leaves take on a vertical orientation. As
the disease develops the veins take on a purple coloration. The symptoms of
this disease are similar to curly top. The two diseases may be separated at
times on the basis of leaf curling, which is more severe with curly top.
~Control: Attempts to control aster yellows have only been partially suc-
cessful. Weed host and vector control is of some value.
---------------------------------------------------------------------------
TOMATO - BACTERIAL CANKER
Cause: A bacterium, Clavibacter michigansis subsp. michigansis (Corynebacteri-
um michiganense), which is carried in or on the seed or survives in tomato
debris in or on the soil. The bacterium may be spread in the seed flat by
handling seedlings and by normal watering. In the field it may be spread by
handling plants, pruning sucker shoots, use of contaminated stakes or trellis-
es, and by rain and irrigation water.
Symptoms: Seedlings may be destroyed or remain stunted.
Occasionally seedlings will not show symptoms until after transplanting into
the field.
Older plants - one or several of the following symptoms may be present:
1. A yellowish-brown discoloration of the vascular tissue in the stem and
petioles. This discoloration is most pronounced at the junction of the stem
and petiole and is almost always present in infected plants.
2. Burning (necrosis) of leaflet margins.
3. Wilting of leaves and curling of leaflets, starting at the base of the stem
and progressing upward. Unilateral wilting of leaves (i.e., one side of the
leaf appears wilted while the leaflets on the other side of the midrib appear
normal) is common. Later, affected leaves become brown, wither, and die.
4. Open cankers on stems, petioles, and/or midribs.
5. `Bird's-eye' spotting on fruit. Brown spots are surrounded by white halos.
Plants may become infected at any stage of growth. When seedlings are infect-
ed, wilting and death may be rapid. With larger plants of fruit bearing size,
severely diseased plants rarely die but are a total loss as far as fruit
production is concerned.
Characteristic field symptom - yellow discoloration in vascular tissues at
axils of leaves as a result of the bacteria collecting at these points. This
discoloration lasts only a short time (1 to 2 hours) if the plant is removed
from the soil. Often when the stem is broken, the pith will pull out from the
stem as a result of the deterioration of the vascular tissues by the bacteria.
Stems-longitudinal open cankers.
Fruit-spots with brown centers and white halo. The spots are the result of
infection by bacteria washed by rain from the stem cankers to the fruit.
~Control:
1. Seed-plant only disease-free seed.
2. Seed and seedling treatment-wrap seed in a cheesecloth bag and soak in 1.05
percent sodium hypochlorite (1 part household bleach to 4 parts water) for 40
minutes. Spread out seed and allow to dry. Then treat seed with thiram (3 oz
ai (slurry) or 4 oz ai (dry)/100 lb).
Beginning at the first true leaf stage, spray seedlings weekly for a minimum
of two applications with a 200 ppm solution of streptomycin sulfate.
3. Soil and flats-use disease-free soil and flats. Treat flats if contam-
inated. Dip for 5 minutes in a chlorine solution (1 part chlorox or other
equivalent solution to 3 parts water). Boiling water or steam may also be
used. It is very important to separate the disease-free flats from contam-
inated soil-polyethylene sheeting is effective and easy to use.
4. Fields - use a 4 year rotation. Plant in disease-free soil if possible.Do
not plant in fields receiving irrigation or drainage water from severely
contaminated fields.
5. Do not handle plants when wet. Snap off suckers with fingers instead of
pruning with a knife. Fumigate contaminated stakes, trellises, wires, flats,
etc., with methyl bromide under a plastic tarp.
---------------------------------------------------------------------------
TOMATO - BLOSSOM END ROT
Cause: Calcium deficiency aggravated by widely fluctuating soil moisture
conditions-nonpathogenic. Calcium in the fruit may be deficient because (1)
insufficient calcium in the soil, (2) excess N, Mg, K or Na has been applied
as fertilizer, (3) very wet or very dry soils interfere with uptake of
calcium, (4) combinations of (1) to (3).
Symptoms: Black leathery lesions form on blossom end of fruit. The affected
area shrinks and causes misshapen fruits. Only some fruits on a plant may be
affected. Green as well as ripe fruits may be affected.
~Control:
Before planting
1. Add lime to adjust pH of soil to 6.8 to 7.2. Mix lime thoroughly in top 8
to 12 inches of soil. Lime is best applied in fall.
2. Use only moderate amounts of additional fertilizers to keep plants normally
green and vigorous but not luxuriant.
3. Do not plant tomatoes where drainage is poor, surface water accumulates, or
soil is droughty.
After Planting
1. Mulch plants with black plastic or loose organic materials.
2. Fertilize with nitrogen side-dressing only if it is required to maintain
green color and moderate-growth. Use calcium nitrate or ammonium sulfate at
rate of .25 lb to 100 sq ft (100 lb/A).
3. Maintain uniform soil moisture. Apply water to wet all soil in root zone
every 7 to 10 days. About 24 hours after watering, dig a small hole with a
trowel to a depth of 1 foot to be certain water has penetrated to that level.
Sprays. If symptoms of blossom end rot are detected, spray the leaves and
fruit with calcium chloride at the rate of 2 T in 1 gal water (4 lb in 200 gal
water/A). Apply two or more sprays at 1-week intervals. The spray may cause
some injury to the margins of the leaves.
---------------------------------------------------------------------------
TOMATO - CURLY TOP
Cause: Curly top virus. The same virus also causes curly top of sugar beets.
The disease may be severe in central and eastern Oregon. Other vegetable crops
such as watermelon, bean, beet, spinach, squash, and pepper, are susceptible.
The virus is disseminated only by the beet leafhopper, (Circulifer tenellus).
Curly top occurs in the Willamette Valley, especially the upper (northern)
valley when the winds blowing through the Columbia Gorge transport the beet
leafhopper from eastern Oregon.
The leafhopper takes up the virus in 1 minute of feeding but the maximum
result is attained when the leafhopper is retained on infected leaves for 2
days. It is then able to keep the virus within its body for the remainder of
its life. An incubation period within the insect's body for 21 to 24 hours or
longer is necessary before it can transmit the virus to another plant, unless
the temperature is very high- then the period may be reduced to 4 to 6 hours.
The virus is never carried in the leafhopper's eggs.
The time between the feeding of the insect and the appearance of curly top
symptoms varies according to the prevailing temperature. When the tempera-
ture is very high, symptoms may show in 24 hours; normal temperatures - 7 to
14 days; cool weather - up to 30 days.
The disease occurs in areas where light intensity is high, summer heat is
prolonged, relative humidity is low, and evaporation is rapid. In years when
the average relative humidity is 35 percent, the disease is very severe; when
it is over 50 percent there is almost no curly top. Shading, which lowers the
light intensity and retards evaporation, probably delays visits of leafhop-
pers, decreases the percentage of infection, and reduces symptom expression.
Symptoms: Pronounced upward rolling and twisting of the leaflets exposing
their undersurfaces, a stiff and leathery condition of the foliage, and a
peculiar dull yellowing of the entire plant. Purpling of leaflet veins and
stunting of the plant often occur. Many of the roots and rootlets are killed.
Severely affected plants die.
~Control: There are no satisfactory methods of control. Possibly the most
practical suggestion for control is the setting out of plants in order to
avoid severe leafhopper attack when the plants are small. In home gardens,
shading the tomato plants will help avoid leafhopper attack. The sugar beet
leafhopper avoids shaded plants.
Attempts to control the leafhopper have not as yet been effective. The
varieties listed below are resistant to curly top. Varieties marked VF are
resistant to Verticillium and Fusarium wilt: `Payette', `Owyhee', `Super Star
VF', `Red Lode VF', `Ida-Red VF', `Parma VF', `Bi-centennial VF', `Rowpac VF',
`Columbia VF', `Rose VF', `Salad Master VF'.
---------------------------------------------------------------------------
TOMATO - DAMPING-OFF (Seed And Seedling Rot)
Cause: Several fungus organisms which live in the soil.
Symptoms: Seedlings rot at the soil line and fall over or may not emerge.
~Control: For the seed rot phase, see Seed Treatment-Vegetables. In the
damping-off phase, allow the surface of the soil to dry, then water with a
copper drench. Copper drenches are prepared by mixing 1 oz of COCS, or any
other fixed or proprietory copper, in 3 gal water. Stir thoroughly, then
sprinkle on the seedbed generously.
Or, where pythium is a problem, apply 4-8 pt Ridomil 2E as a broadcast surface
spray immediately before or after planting in 20-50 gal of water. Lightly
incorporate if application is made before planting or with sprinklers if
applied after planting. Band application may also be used - see product
label. Rotation crop restrictions apply - see product label.
Or, use Anchor at 1.5 flowable oz/cwt seed.
---------------------------------------------------------------------------
TOMATO - EARLY BLIGHT
Cause: Alternaria solani, a fungus. The fungus also causes early blight of
potatoes. It attacks eggplant, horsenettle, nightshade, and other wild plants
related to tomato.
The fungus may occur on or in the seed, but internal infection is rare in seed
produced commercially. The fungus can live in decayed plant refuse in the
soil.
Symptoms: Small, irregular, brown, dead spots usually first appear on the
older leaves. The spots enlarge until they are 1/4 to 1/2 inch in diameter. As
they enlarge they commonly show ridged concentric rings in a target pattern
(bull's-eye pattern). The leaf tissue around the spots turns yellow. If the
spots are numerous, the entire leaf will be yellowed. Some spotting of the
older leaves may occur in the early season, but the greatest injury usually
occurs as the fruit begins to mature.
Dark, leathery, sunken spots appear on affected older fruits.
The spots may be quite large and show concentric markings similar to those on
diseased leaves. The dark, dry decay may extend to some depth into the fruit.
~Control: Spray at 7 to 10 day intervals with Bravo, mancozeb, or Maneb. Spray
at 14 day intervals with Ridomil/Bravo 8lW. In home gardens bordeaux 8-8-100
or fixed coppers are effective if applied regularly.
Residues:
Anilazine (Dyrene)-Use 1 to 2.5 lb ai/A per application. Do not apply more
than 30 lb Dyrene 50 WP per season. Do not apply within 3 days of harvest.
Tolerance 10 ppm.
Chlorothalonil (Bravo)-Use 1.125 to 1.5 lb actual/A. Tolerance 5.0 ppm. This
material is available as Daconil 2787 for home gardens.
Copper-exempt.
Mancozeb - Do not apply within 5 days of harvest.
Maneb - Apply at 1.2 to 1.6 lb ai/A. Do not apply more than 6.4 lb
ai/A/season or within 5 days of harvest.
Ridomil/Bravo 8lW - rotation crop regulations apply, see product label.
---------------------------------------------------------------------------
TOMATO - FRUIT ROTS
Cause: Many fungus and bacterial organisms.
Symptoms: Fruit rots from small necrotic spots to complete fruit rotting.
~Control:
1. Prompt cooling after harvest. Avoid harvest cuts, bruises, and cracked
fruits.
2. Much of the rot can be avoided by staking or supporting the tomatoes in
some manner so they do not touch the ground.
---------------------------------------------------------------------------
TOMATO - LATE BLIGHT
Cause: Phytophthora infestans, a fungus which also attacks potatoes.
Symptoms: Brown or black lesions begin on leaf veins, petioles, and stems.
Cool, wet weather favors disease development, and hot, dry weather checks the
advance of the fungus in infected parts. On fruits, gray-green, water-soaked
spots form which enlarge, coalesce, and turn dark.
~Control: Spray at 7 to 10 day intervals with Bravo, Maneb, mancozeb, Ridomil
MZ58, Ridomil Copper, or Ridomil/Bravo 8lW at 14 day intervals. Bordeaux
8-8-100, chlorothalonil, or fixed coppers are effective if applied regularly
in home gardens.
Residues:
Chlorothalonil (Bravo)-Use 1.125 to 1.5 lb actual/A. Tolerance 5 ppm. This
active ingredient is available as Daconil 2787 for the home gardener.
Copper-Exempt.
Mancozeb - Do not apply within 5 days of harvest.
Maneb - Apply at 1.2 to 1.6 lb ai/A. Do not apply more than 6.4 lb
ai/A/season or within 5 days of harvest.
Ridomil/Bravo 8lW - rotation crop limitations apply. See product labels.
Ridomil MZ58. Do not apply within 5 days of harvest.
---------------------------------------------------------------------------
TOMATO - LEAF MOLD
Cause: Cladosporium fulvum, a fungus. In the Pacific Northwest, leaf mold is a
disease of greenhouse tomatoes. The spores are resistant to drying and may
survive about the greenhouse for several months after the plants have been
removed.
Symptoms: White spots which rapidly enlarge and become yellow appear on the
upper surfaces of the older leaves. The lower surfaces of the patches become
covered with a velvety, olive-brown fungus growth. When the disease is severe,
much of the foliage is killed and the crop is greatly reduced.
~Control: The fungus is most destructive when the humidity is high (90 to 100
percent at the leaf surface) and temperature ranges from 65 to 80 F. The
disease usually will not be severe if the relative humidity at the leaf
surface is kept below 90 percent.
Leaf mold can be kept under control if there is ample ventilation and good air
circulation in the houses. A temperature of 60 to 65 F, at least, should be
maintained. Night heating is often practiced, when the outside air drops below
60 F, to reduce the increase in humidity that comes with the lowering of the
outside air temperature.
Varieties reported to be resistant to some strains of the fungus are: `Santa
Fe', `Globelle' (pink fruit), `Bay State' (red fruit), and `Vetomold' (red
fruit).
Spraying for the control of leaf mold in greenhouses has not been very
successful because of the difficulty of covering the undersurfaces of the
leaves.
Treatment of the greenhouse with a thermal aerosol of termil has reduced loss
with this disease. Use one 3.5 oz (20 percent) smoke generator per 1,000 sq ft
of area or one 8 gram (90 percent) thermal tablet per 400 sq ft of area. Do
not apply when greenhouse temperature is above 75 percent F.
Residues: Termil-tolerance 5 ppm. No time limitations.
---------------------------------------------------------------------------
TOMATO - MOSAIC
Cause: Tobacco mosaic virus. The virus also affects peppers, eggplants,
petunias, and many other solanaceous plants. The virus is easily spread by
handling mosaic-affected and healthy plants in transplanting, brushing against
plants during hoeing or cultivating, and when tying and pruning the vines. The
virus is carried by certain species of aphids, but these insects are not as
important as human beings in the general spread of the disease. Since the
virus is present to some extent in cigar, cigarette, and pipe tobaccos, it is
probable that the greatest portion of the initial mosaic infection of tomato
seedlings can be traced to this source.
Symptoms: Foliage becomes mottled with alternating yellowish and dark-green
spots. Leaves are frequently fernlike in appearance. Sometimes necrotic spots
or streaks develop on stems and leaves.
~Control: See Tomato--Variety Selection below for resistant varieties. Wash
hands with soap and water before handling plants. Do not smoke while handling
tomato plants since about 80 percent of cigarettes contain tobacco carrying
the virus. Use clean soil each year in seedbeds or sterilize the old soil.
---------------------------------------------------------------------------
TOMATO - NEMATODE (Root-Knot)
Cause: Meloidogyne hapla. Root-knot nematodes are found nearly everywhere and
are the only known nematode pest of Oregon vegetables grown under glass. The
nematodes are usually introduced with infested soil or mulch materials and in
transplants.
Symptoms: Infected plants are stunted and produce little or no fruit. Conspi-
cuous wilting occurs during warm weather. Knots or galls of infected roots are
usually much larger and more numerous on greenhouse-grown crops than on the
same crops grown outdoors.
~Control:
1. Plant resistant varieties. See varietal list under Tomato Wilt.
2. Prevent introduction of nematodes by the use of nematode-free plants;
fumigate soil prior to bringing it in greenhouse; grow seedlings in
nematode-free soil.
3. Soil fumigation with Telone II or Vapam prior to planting.
4. Many resistant varieties are available. See Tomato - Variety Selection.
Residues:
Telone II preplanting soil fumigation - allow 2 to 3 weeks to elapse between
time of application and planting, or wait until odor has left soil. Do not
treat extremely heavy soils. Considered to be a nonfood use.
Vapam preplanting soil fumigation - Expose to fumigant for 7 days, then culti-
vate top 2 inches to increase aeration. Planting time varies with soil type,
quantity applied, and soil temperature. Under best conditions 14 to 21 days
are required to prevent phytotoxicity. Considered to be a nonfood use.
Sampling: Root-knot nematodes are sedentary endoparasites (see Nematodes--
Life History), and only second-stage juveniles (the infective stage) and adult
males (which may be rare) are present in the soil. Before planting crops
susceptible to root-knot nematodes, take soil samples with sufficient lead
time to implement management procedures if necessry. 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. When sending samples for diagnosis, include roots as well as soil.
Reference: See Soil Fumigants.
------------------------------------------------------------------------------
TOMATO - POWDERY MILDEW
Cause: A fungus, Leveillula taurica, that has occurred at only a scattering of
sites in the Pacific Northwest.
Symptoms: Yellow blotches of irregular shape on the leaves that later turn
necrotic. The fungus usually can be found on the lower side of the leaf, but
it sporulates only sparsely. Sometimes the lesions develop concentric ridges
that mimic early blight. Individual leaves die and continue to hang on the
plant.
~Control: Usually the disease does not require control measures because it
occurs late in the season. When control is ncessary, wettable sufur or sulfur
dust will control the disease. Check label of particular products for rates
of application.
---------------------------------------------------------------------------
TOMATO - SEED TREATMENT
Aids in control of seed decay and damping-off.
Anchor flowable at 1.5 fl oz/cwt seed.
Thiram -- use labeled rate of product.
Captan -- use labeled rate of product.
Residues: Thiram - Do not use more than 4 oz actual/100 lb of seed (dry). Do
not use more than 3 oz actual/100 lb of seed (slurry). Tolerance 7 ppm.
---------------------------------------------------------------------------
TOMATO - TOMATO SPOTTED WILT VIRUS (Tip Blight)
Cause: A virus which is transmitted from plant to plant by thrips (an insect).
Many ornamental plants (dahlias, asters, zinnias) are carriers of the virus.
Symptoms: Bronze-colored markings develop on the upper side of the leaflets.
Veins on undersurface turn purple, and there is upward rolling of leaves.
Small, circular necrotic spots may also appear on the leaves. The necrosis
spreads to the growing tip causing it to wilt and die. On green and red
fruits, yellowish spots appear often with concentric zones of yellow, bronze,
green, pink, or red. This fruit-spotting is the best symptom for diagnosis.
~Control:
1. Do not grow vegetable transplants in greenhouses that contain TSWV-infected
ornamentals.
2. Spray for thrips control.
3. Remove and burn infected plants.
4. Do not set out fields adjacent to ornamental plantings.
---------------------------------------------------------------------------
TOMATO - STREAK (Combination Streak)
Cause: The combination of tobacco mosaic virus and potato virus `X' in tomato
produce the tomato streak disease.
Symptoms: Necrotic leaf spots appear followed by the death of both leaves and
stems. The whole plant may be killed. Fruits are distorted or may not form.
~Control: Do not use tobacco while handling tomato plants. Wash hands after
handling potatoes if tomatoes are to be handled.
---------------------------------------------------------------------------
TOMATO - VARIETY SELECTION
Varieties are listed below by their resistance to Verticillium and Fusarium
wilts and root-knot nematode.
Tomato Variety Resistance
Variety Maturity Date Resistance*
`Better Boy' Late VFN
`Better Boy F.' Early VFN
`Big Set' Late VFN
`Carmen' Late VFNT
`Carnival' Late VFNT
`Casino Royale' Mid VFNT
`Cavalier' Late VFNT
`Celebrity' Late VFNT
`Chico III' Mid F
`First Lady' Mid VFNT
`Heinz 1350' Mid VF
`Heinz 1370' Late F
`Jetstar' Mid VF
`Merced' Mid VFT
`Milagro' Late VFNT
`New Yorker' Early V
`Pik Red F.' Early VFN
`Pik Rite F.' Early VFN
`President' Mid VFNT
`Red PAK' Mid VF
`Royal Flush' Early VFN
`Rutgers' Early F
`Santa Fe' Late VF
`Small Fry' (cherry tomato) Early VFN
`Spring Giant' Early VF
`Spring Set' (F. hybrid) Early VF
`Sunny' Mid VF
`Sunray' (yellow tomato) Mid-late F
`Supersonic' Mid VF
`Toy Boy' (cherry) Early VFN
`VF Fireball' Mid-late VF
`VFN-8' Mid-late VFN
`VFN Bush' Mid VFN
`Wonderboy' Late VFN
---------------------------------------------------------------------------
* V = Resistant to Verticillum wilt
F = Resistant to Fusarium wilt
N = Resistant to root-knot nematode
T = Resistant to Tobacco Mosaic Virus
----------------------------------------------------------------------------
TOMATO - WHITE MOLD
Cause: A fungus, Sclerotinia sclerotiorum, that attacks numerous other hosts
and overwinters as hard, black sclerotia in soil and debris. The fungus will
enter any organic debris such as old leaves or blossoms. The fungus usually
grows from these materials into the healthy portions of the tomato plant.
Symptoms: The first symptoms are a rapidly expanding soft rot usually
centered on a piece of organic material (old leaves, flower petals, etc.).
When conditions become drier, sometimes the gray area is covered with white,
cottony mycelium. Hard, black irregularly shaped sclerotia develop in the
mycelium and within the stem tissue of the tomato.
~Control: No fungicides are registered for use on this fungus on tomatoes.
Avoid dense planting to allow the lower portion of the plant to dry out
between irrigations. A few deep irrigations are better than frequent shallow
ones.
---------------------------------------------------------------------------
TOMATO - WILT
Cause: Either Fusarium oxysporum or Verticillium albo-atrum, fungus organisms
that live in the soil.
Symptoms: Yellowing of the lower leaves which wilt and die as the disease
progresses upward. The vascular system is discolored. Plants are seldom
completely killed by either fungus, unless infected when very young, but
growth is retarded and yields are low.
~Control: Use resistant varieties. Many VF lines are available from seed
companies. See Tomato-Variety Selection.
---------------------------------------------------------------------------
TOMATO - YELLOW SHOULDER
Cause: Yellow shoulder, sometimes also referred to as blotchy ripening, is a
physiological disorder. It is associated with poor potassium fertilization,
high temperatures and excessive short-wave radiation and an increased radia-
tion load. It is also more common in green-shoulder fruited varieties.
Symptoms: This disorder is expressed as a yellow or yellow-orange discolor-
ation in the shoulder region, separated from the red tissue by a distinct
line of demarcation. The yellow tissue never turns red even after prolong
storage. Severity may vary from discoloration in only several millimeters of
tissue next to the stem scar, to discoloration of almost the entire stem half
of the fruit. Internal symptoms are expressed as white pericarp and septa
tissue that can be shallow or extend through the entire fruit.
~Control: Harvest fruit in the mature-green stage and room ripen. Avoid sus-
ceptible varieties, especially those with green shoulder fruit. Use varieties
with good leaf cover. Maintain adequate potassium levels in the soil.
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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
Extension Agent, or Dr. N. S. Mansour, Department of
Horticulture, Oregon State University, Corvallis, OR
9733l.
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