From: Brian Lo <dragon@csulb.edu>
Newsgroups: rec.gardens
Subject: FAQ: Zucchini, and Squashes
Date: Wed, 1 Mar 1995 14:53:55 -0800
ZUCCHINI and SUMMER SQUASH
Cucurbita pepo
Summer squash, has been defined as fruits of the Cucurbitaceae family
that are consumed when immature, 100% of the fruit of which is edible either
cooked or raw, once picked it is not suited for long-term storage, has a soft
rind which is easily penetrated, and the seeds of which would not germinate:
e.g. Cucurbita pepo (i.e. crookneck squash, straightneck squash, scallop
squash, zucchini, vegetable marrow); Lagenaria spp. (i.e. hyotan, cucuzza);
Luffa spp. (i.e. hechima, Chinese okra); Memordica spp. (i.e. bitter melon,
balsam pear, balsam apple, Chinese cucumber); and other varieties and/or
hybrids of these.
VARIETIES (Days to harvest are given for the Willamette Valley; warmer areas
subtract 10-15 days).
Zucchini (approximately 60 days):
Dark Green: Elite, Aristocrat, Ambassador, Black Jack, Black Magic,
Onyx, Zuchlong. For trial: Seneca Milano, Green Magic, Raven.
Medium Green: Ambassador, Chefini, Storr's Green, President. For
trial: Embassy (open plants, mostly spineless).
Gray Green: Greyzini, Caserta (bulbous - for specialty markets).
Yellow: Gold Rush, Eldorado, Rocky Gold, Butter Stick, Gold Finger,
Goldbar. For trial: Golden Dawn II.
Other Summer Squash (approximately 55 days):
Yellow Straightneck: Sunbar, Superpik, Multipik, Enterprise, Golden Girl.
Yellow Crookneck: Supersett, Cracker, Sundance, Tara, Early Golden, Goldie,
Sunrise, Dixie Hybrid.
Note: Jersey Golden, Sunbar, Superpik, Multipik and Supersett are squash
varieties with a gene for precocious yellow fruit. These start out yellow
rather than green, and may be used for yellow baby squash. This character
also provides some degree of tolerance to WMV II virus (water melon mosaic
virus II) by masking mosaic symptoms for a short time allowing several
harvests before fruit damage becomes severe. Fruit stems are also yellow
instead of green.
Scallop: Peter Pan, Patty Green Tint, Scallopini, Early White Bush Scallop,
Scallopini; Sunburst (yellow scallop). For trial: Star Flower.
Specialty Oriental vine crops:
Vegetable Sponge, Dish-cloth gourd, Sponge gourd (Luffa sp.). These may
be used for cooking when immature (approximately 75 days), or allowed to
mature for the fiberous spongy tissue (approximately 115 days): Angular types
(Luffa acutangula): San-C, Ping-Ann. Cylindrical types (Luffa aegyptica):
Cylinder, Seven Star, Seven Beauty. These produce higher quality sponge
fiber.
Balsam pear, Bitter melon (Momordica charantia; approximately 75 days):
Green: Known-You Green. White: Moon Shine, Known-You No.2
SEED COMPANIES
Abbott & Cobb Inc. POB F307, Feasterville, PA 19047
American Takii Inc., 301 Natividad Rd. Salinas, CA 93906 ph:408/443-4901
Asgrow Seed Company, POB 5038, Salinas CA 93915
Ferry-Morse Seed Co. POB 4938, 555 Codoni Ave. Modesto, CA 95352
Harris Moran Seed Co. 3670 Buffalo Rd. Rochester, NY 14624
Johnny's Selected Seeds, Foss Hill Rd. Albion, ME 04910
Known-You Seed Co., Ltd., 26, Chung Cheng 2nd Rd., Kaohsiung, Taiwan, ROC
La Marche Seeds International, POB 190, Dixon, CA 95620
Nickerson-Zwaan Seed Co. POB 1787, Gilroy, CA 95021
Petoseed Co. Inc. POB 4206, Saticoy, CA 93303
Rogers N.K. Seed Co. POB 4272, Boise ID 83711
Royal Sluis Inc. 1293 Harkins Rd. Salinas, CA 93901
Sakata Seed America Inc. POB 880, 18095 Serene Dr. Morgan Hill, CA 95038
408/778-7758
Stokes Seeds Inc. POB 548, Buffalo, NY 14240
Sunseeds, 2320 Technology Pkwy. Hollister, CA 95023
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
SEED AND SEED TREATMENT
Zucchini and most summer squash seed numbers approximately 200-300 per
ounce. Use fungicide treated seed. Summer squash seedlings are susceptible
to damping off and decay when soils are cool and wet.
SOIL
Zucchini grow best on fertile, well-drained soil supplied with organic
matter. The ideal pH for zucchini growth is between 6.0 to 7.5, but they will
grow on soils with a pH of up to 8.0. Consult a soil test for fertilizer and
liming recommendations.
SOIL TEMPERATURE
The minimum soil temperature required for germination of zucchini is 60
F, with the optimum range between 70 and 95 F.
SEEDING
Zucchini are usually direct-seeded when all danger of frost has passed.
In western Oregon planting begins in early May and extends to mid July.
Use 36-40 inch spacing between row with plants 24-30 inches apart within
the row.
FERTILIZER
A soil test is the most accurate guide to fertilizer requirements. The
following recommendations are general guidelines:
The optimum pH range is 5.8-7.0.
Apply 10 tons/acre of manure in the spring when available.
Western Oregon - At time of seeding, band 2 in. to the side of the
seed and 3 in. deep the following:
Nitrogen: 50-70 (N) lb/acre. (Side-dress with an additional 30-60 lbs.
per acre of nitrogen when plants begin to flower).
Phosphate: 115-125 (P2 O5) lb/acre.
Potash: 50-100 lbs K2 O/acre (broadcast and disked-in prior to seeding).
Eastern Oregon - At time of seeding, band the following:
Nitrogen: 40-60 (N) lb./acre
Phosphate: 115-125 (P2 O5) lb/acre
Potash: 50-100 lbs K2 O/acre (broadcast and disked in prior to seeding).
Side-dress with 25-50 lb/acre of nitrogen or where mulching and trickle
irrigation are practiced, nitrogen can be fed through the trickle irrigation
system at 15-25 lb./acre when the vines begin to spread. 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 l0-50 ppm chlorine
solution. Chlorinate more frequently if the flow rate decreases.
IRRIGATION
Zucchini root depth is relatively shallow. Maintain soil moisture above
60% of the soil water holding capacity. In western Oregon, 12-15 inches of
irrigation may be necessary. 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. It is important to regulate irrigations properly to
avoid excessive moisture or water stress.
FLOWERING AND POLLINATION
Zucchini and summer squash plants bear separate male and female flowers
on the same plant (monoecious). Only the female flowers set fruit. Bees
transfer pollen from male flowers to female flowers, making fruit set possi-
ble.
It is recommended that one honey bee hive should be introduced for every
1 to 2 acres during the blooming period since native bee populations may not
be adequate, or may not coincide properly with the blooming period.
GROUND MULCHES AND ROW COVERS
Black plastic ground mulch is sometimes used in the production of summer
squash. It increases yield and earliness of zucchini. A new generation of
plastic mulch films allows for good weed control together with soil warming
that is intermediate between black plastic and clear film. These films are
called IRT (infra-red transmitting) films. They are more expensive than black
or clear films, but appear to be cost-effective where soil warming is impor-
tant.
Spunbonded polyester and perforated polyethylene row covers may be used
for 4 to 8 weeks immediately after transplanting or seeding especially for
summer squash (such as zucchini) where the added cost could be recovered
through increased early season prices. Covers should be removed when plants
begin to flower to allow proper pollination. 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 many cases
total yields.
A new insect exclusion cover (Agryl P-10), is very light weight, offe-
ring season long insect vector exclusion without affecting canopy temperature
very much. It is recommended for trial in situations were conventional virus
vector control procedures are inadequate, and market economics justify. It
must be frequently manipulated; removed to allow bee pollination, and re-ap-
plied as necessary to excluding aphid virus vectors.
HARVESTING, HANDLING AND STORAGE
In the Willamett Valley, summer squash and zucchini is harvested for
processing from July 7 to September 20. The prime harvest period is from July
25 to August 25.
Yields of zucchini for processing of approximately 20-25 Tons/acre can
be obtained form multiple harvests with zucchini planted at 24x36 inch
spacings. Fresh market yields are approximately 150 to 300 cwt./acre depend-
ing on the number of pickings.
Zucchini and summer squash can be harvested anytime the fruits reach a
desired size but before they forms hard seeds or rinds. For processing,
zucchini is graded by diameter: Grade #1: 1"-2"; #2: 2"-2.5"; #3: 2.25"-2.50";
anything over 2.5" is rejected.
Cut fruit from the vine, leaving a piece of stem with the fruit.
Harvest every 2-3 days in warm weather.
STORAGE (quoted form USDA Ag. Handbook # 66):
Store zucchini and summer squashes at 40 to 50 F and 95% relative
humidity. Summer squashes, such as Yellow Crookneck, Yellow Straightneck,
White Scallop, Zucchini, and other soft-skin types are harvested at the
immature stage for best quality. They are quite perishable, as the skin is
tender and easily wounded in handling. Small fruits are more desirable than
large ones because they have a more tender flesh and a slightly sweet flavor.
Normally they should not be stored except long enough to accommodate
normal marketing delays such as holidays and weekends. They can be held 1 or
2 days below 40 F with no discernible damage, but such exposure should be
avoided as summer squash is chilling sensitive. Holding summer squash longer
than 4 days at 32 F will cause chilling damage and more rapid deterioration.
The recommended temperature range is 41 to 50 F with 95% relative
humidity. The storage life of summer squash is only 1 to 2 weeks. If storage
of yellow squash extends beyond a week and distribution is involved after
removal, storage at temperatures of 45 to 50 F is best. The storage period at
45 to 50 should be limited to 2 weeks or less. Recent research has shown that
41 F is best for Zucchini squash stored up to 2 weeks. Storage in low-oxygen
atmospheres was of little or no value for Zucchini squash held at 41 F.
PACKAGING
Zucchini and summer squash are usually packaged in 21 pound 5/9 bushel
crates and cartons; 24-28 pound cartons and L.A. lugs; 18-22 pound three-
quarters lugs; 41 pound 1-1/9 bushel crates; or 21 pound l/2 bushel baskets
and cartons.
PEST CONTROL FOR ZUCCHINI AND SUMMER SQUASH
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.
WEED MANAGEMENT GENERAL STRATEGY
Weed management in cucurbits represents planning and integration of several
practices. Crop rotations and, therefore, field selection containing control-
lable weeds must be achieved before planting. Many growers use a stale
seedbed technique followed by cultivation, except in excessively wet years.
Row spacings that enhance canopy development and cultivation are sometimes
supplemented with a herbicide that selectively controls weeds within the crop
row. In eastern Oregon, rye windbreaks often are planted between rows and
incorporated during the last cultivation.
______________________________________________________________________________
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 oil concentrate according to label specifications, taking
care to avoid anionic formulations that react in the tank to form in-
soluble 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.)
______________________________________________________________________________
PREPLANT INCORPORATED
Weed Treatment Active Ingredient Per Acre and Application Comments
------------------------------------------------------------------------------
bensulide 5 to 6 lb ai/A
Prefar
Apply preplant and incorporate 0.5 to 1 inch deep simultaneously or
immediately after application by cross-disking or using a PTO rotary
tiller. Sometimes the first flush of weeds must be controlled with
cultivation before herbicide begins to control grass. Consult label
for planting sensitive crops within 18 months. Do not apply more than
once every 12 months. (Inhibits roots of seedlings).
______________________________________________________________________________
PREEMERGENCE
Weed Treatment Active Ingredient Per Acre and Application Comments
------------------------------------------------------------------------------
ethalfluralin 1.12 to 1.69 lb ai/A
Curbit
Adjust rates depending on texture and organic matter. Apply only as a
postplant surface treatment before weed emergence. Activate with 0.5
inch irrigation within 2 to 5 days or cultivate soil surface above seed.
Crop injury may occur with excessive rainfall or irrigation or if
seeding depth is too shallow. Do not graze, nor apply to wet or cloddy
soils. Note replanting restrictions for sugar beets and red beets
listed on label. (Inhibits mitosis, primarily in shoots)
______________________________________________________________________________
POSTEMERGENCE
Weed Treatment Active Ingredient Per Acre and Application Comments
------------------------------------------------------------------------------
sethoxydim 0.19 to 0.28 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 fertil-
ity. Resistant grasses include annual bluegrass and all fine fescues,
whereas quackgrass can be suppressed. Do not apply within 14 days of
harvest, nor exceed 3 pints/A per season. (Inhibits fatty acid produc-
tion, cell membranes, and new growth.)
______________________________________________________________________________
POSTEMERGENCE LAY-BY TREATMENTS
Weed Treatment Active Ingredient Per Acre and Application Comments
------------------------------------------------------------------------------
ethalfluralin 1.12 to 1.69 lb ai/A
Curbit
Adjust rates depending on soil textures and organic matter. Apply in
bands between rows after planting or transplanting. Activate with 0.5
inch irrigation within 2 to 5 days or cultivate soil 1 to 2 inches deep.
Do not graze or apply to wet cloddy soils. Note replanting restrictions
for sugar beets and red beets listed on label. (Inhibits mitosis,
primarily in shoots.)
------------------------------------------------------------------------
DCPA 9 lb ai/A
Dacthal
Performs poorly in western Oregon. Elsewhere, apply after plants have 4
to 5 true leaves following a cultivation and weeding, but before any new
weeds become established. Results are improved if rainfall or overhead
irrigation occurs immediately after application. Consult label for
restrictions on planting sensitive crops within 8 months. (Inhibits
mitosis).
______________________________________________________________________________
______________________________________________________________________________
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
---------------------------------------------------------------------------
Bean aphid, Dibrom - 1 to 2 lb
Aphis fabae
Melon aphid, diazinon - 0.5 to 0.75 lb
Aphis gossypii Squash only.
Potato aphid,
Macrosiphum euphorbiae malathion - 1 to 1.75 lb
Black, yellow, green, or pinkish Metasystox-R - 0.375 to 0.5 lb
plant lice. Feed on foliage.
Phosdrin - 0.25 lb
---------------------------------------------------------------------------
Nitidulid beetles Effective chemicals previously
different species used for control are no longer
registered for use.
Shiny black beetles 3/32 inch long.
Pollen-seeking adults damage flowers.
Browned flowers are unattractive to
pollinators.
---------------------------------------------------------------------------
Slugs metaldehyde baits
---------------------------------------------------------------------------
Spider mites Kelthane 35W - 0.6 lb spray
Tetranychus spp.
Tiny spiderlike animals feed on
undersides of foliage and cause
yellowing and browning of leaves.
---------------------------------------------------------------------------
Cucumber beetles including rotenone - 0.3 lb
Striped cucumber beetle
Acalymma trivittatum methoxychlor - 1 to 3 lb
Small, slender, greenish-yellow Dibrom - 1.0 lb
beetles with three prominent
stripes on back. Larvae feed on carbaryl - 1 lb
roots and underground parts of stem.
Western spotted cucumber beetle Asana - 0.03 to 0.05 lb
Diabrotica undecimpunctata
malathion - 1.75 lb
Yellowish-green, black-spot-
ted beetle. Damage usually
limited to young plants.
---------------------------------------------------------------------------
Squash bug Asana - 0.03 to 0.05 lb
Anasa tristis
carbaryl - 1 lb. Very hazardous
Large, grayish, sucking insects. to pollinating bees.
Adults and nymphs kill leaves and vines.
Apply dust around base of plant. Avoid permethrin - 0.1 to 0.2 lb
dusting foliage if possible.
---------------------------------------------------------------------------
Wireworms diazinon - 3 to 4 lb active
Limonius spp. ingredient. Broadcast the
granules or emulsifiable for-
Brown, jointed larvae of click mulations evenly on the soil
beetles. Kill young plants, surface and incorporate into
weaken older ones. the top 4-8 inches of soil.
Telone II or C-17 - preplant
______________________________________________________________________________
______________________________________________________________________________
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.
ROOT ROT AND STORAGE ROT
Cause: Sclerotinia sclerotiorum, a fungus. This fungus overwinters in the
ground on old infected plant material.
Symptoms: A white cottonlike mold develops on the plant stem near the ground.
The disease--a watery soft rot--causes greatest losses in pumpkins or squash
piled in the open, or in storage, following preharvest infection.
~Control:
1. Remove infected plants as soon as found.
2. Deep plowing and crop rotation have had some beneficial effect.
3. Pumpkins and winter squash store best if properly cured. They should be
cured at temperatures of 80 to 85 F and a relative humidity of 85 percent for
a period of 5 to 10 days. Curing encourages the healing of cuts and bruises.
Storage requires a temperature of 50 to 60 F and a relative humidity of 80
percent. At no time should the pumpkins be allowed to become wet during
storage. They should have stems removed before storing.
4. See also Squash--Storage Rots.
---------------------------------------------------------------------------
ALTERNARIA LEAF SPOT AND FRUIT ROT
Cause: Alternaria cucumerina, a fungus that overwinters in and on soil and in
infected plant debris.
Symptoms: At first small brown spots on fruit and leaves which turn black as
the disease progresses. The spots on the leaves take on a target spot or
ringed appearance. The fruit decay is dry and tough on the surface but moist
and spongy in the interior of the squash.
~Control:
1. Use a 2 to 3 year rotation out of cucurbits prior to planting squash.
2. Spray Bravo 720 at 2 to 3 pt/A in sufficient water to cover. May be
applied through sprinkler systems. See label for further directions.
3. Apply Maneb at 1.2 to 1.6 lb ai/A. Do not apply more than 12.8 lb
ai/season. Do not apply within 5 days of harvest.
---------------------------------------------------------------------------
ASTER YELLOWS
Cause: A mycoplasma like organism transmitted by several leafhoppers.
Symptoms: Plants are chlorotic, dwarfed, and many secondary shoots develop
from the leaf axil. Numerous shoots also develop from axils of leaves on the
secondary shoots giving the plant a bushy or witches broom appearance. Some
younger leaves show vein clearing and most are dwarfed, yellow, and misshapen.
All leaves are usually stiff, rigid, and somewhat thickened with enlarged
midribs and lateral veins. Fruits are small, malformed, and lighter than
normal in color.
~Control: No attempts at control of aster yellows have been completely success-
ful. Control of weed host in combination with leafhopper control is of some
value.
---------------------------------------------------------------------------
BLACK ROT OR GUMMY STEM BLIGHT
Cause: A fungus, Didymella bryoniae, which overwinters on crop refuse and
attacks numerous other cucurbits.
Symptoms: On leaves and stems the fungus causes brown to black circular spots.
There is usually a spot of gummy substance in the center of the spot. On
fruit, the fungus causes water-soaked spots of circular shape. The lesions
usually have a drop of gummy exudate in the center. Later the spot becomes
covered with white mycelium and the tiny black pycnidia and perthecia of the
fungus. The fungus causes a dry rot of flesh of the squash.
~Control:
1. Store only perfectly healthy fruit. A small wound, such as a fingernail
scratch, is sufficient for disease development.
2. When harvested, winter squash should be cured for 2 weeks at 75 to 85 F.
3. The use of plastic mulch prevents infection of the squash that rests on
the mulch.
4. The fungus will not grow below 50 F. Squash should be stored slightly
below this temperature if possible.
5. Rotation out of cucurbits for at least 2 years is the best control because
the fungus will not survive without cucurbit refuse.
6. Spray with benomyl .125 to .25 lb ai/A in water to cover or .25 lb ai/5 to
10 gal of water/A by air.
7. Spray with chlorothalonil (Bravo 500) at the rate of 2.75 to 4.25 pt of
product/A. Bravo 720 may be applied through sprinklers. See label for
directions.
8. Apply Maneb at 1.2 to 1.6 lb ai/A. Do not apply more than 12.8 lb
ai/season or within 5 days of harvest.
Residues:
Benomyl--Tolerance 1.0 ppm. Limits--0.25 lb ai/A. No time limitations.
Chlorothalonil (Bravo)--Tolerance 5 ppm. No time limitation.
---------------------------------------------------------------------------
CURLY TOP
Cause: A virus.
The virus is transmitted by the sugar beet leafhopper.
Symptoms: Young infected plants die almost immediately without showing
characteristic symptoms. On older plants the mature leaves gradually yellow
and die. New growth on these plants is dwarfed, internodes are shortened, and
leaves develop a savoyed surface or roll upwards at the margins. Bending
upwards is characteristic of the tip of the runner. Blossoms on the diseased
shoots usually do not set fruit.
---------------------------------------------------------------------------
DAMPING-OFF
Where Pythium spp. are a problem, use 4 to 8 pt of Ridomil 2E/A in 20 to 50
gal of water as a broadcast, band, or lightly incorporated broadcast. Rates
vary with application method. See product label.
Or, use Anchor flowable at 1.5 fl oz/cwt seed.
---------------------------------------------------------------------------
POLLINATION FAILURE
Cause: Lack of pollen or inactive pollen.
Symptoms: Fruits fail to enlarge and brown from blossom end. Blossoms fall
off. Sometimes a portion of the fruit develops normally while the remainder
does not enlarge, resulting in bottle-shaped or dumbbell-shaped fruit.
~Control: Provide adequate pollinizers, at least one beehive/A. Sometimes
waiting for warm weather will increase pollination.
--------------------------------------------------------------------------
ROOT ROT
Cause: Fusarium sp.
Symptoms: Soft mushy rot of the stem. Stem turns dark brown at the base.
Wilting and collapse of vines during hot weather.
~Control: Long rotation.
---------------------------------------------------------------------------
SCAB
Cause: The fungus, Cladosporium cucumerinum, which overwinters in cucumber
debris, in cracks of greenhouses, and on the seed.
Symptoms: The fungus causes severe injury on the fruit which can be infected
at all stages of growth, but which is particularly susceptible while young.
At first, a sticky substance is exuded in drops as if the trouble were the
result of an insect puncture. Spots then gradually turn gray, become slightly
sunken, and enlarge to about 1/8 inch in diameter. The canker gradually grows
darker and the tissue collapses further into the squash until a pronounced
cavity is formed, which is lined with a dark-green velvety layer of the
fruiting fungus.
The first symptom of foliage is the appearance of a slightly water-soaked
paler-green area between the veins, as well as on them. These spots usually
are numerous. Gradually the spots turn gray to white and become angular. The
fine veinlets in the spots may remain brown or tan and are distinct against
the white background. The dead tissue cracks, breaking away until the whole
leaf has a ragged appearance.
The spores are disseminated by insects, clothing, tools, and are blown long
distances in moist air. Host penetration takes place in less than 9 hours
following germination, and visible infection in 3 days. Spore production may
occur on the fourth day.
~Control: Spray benomyl 2 to 4 oz ai/A ground or 4 oz ai/A air, or Bravo 720
at 2 to 3 pt/A at 7- to 10-day intervals.
Residues:
Benomyl--Tolerance 1.0 ppm.
Chlorothalonil (Bravo)--tolerance 5ppm.
--------------------------------------------------------------------------
SQUASH-ZUCCHINI YELLOW MOSAIC VIRUS (ZYMV) AND WATERMELON MOSAIC VIRUS II.
Cause: A virus spread by aphids and mechanical means such as equipment, and
pickers hands' and clothing.
Symptoms: Yellow and green mosaic of the leaves. The leaves are usually
distorted and the plants are stunted. Fruits are mottled and irregular-shaped
and are frequently unmarketable.
~Control: Control of this disease has been difficult because aphids can move
the virus from weed hosts over relatively long distances. The control
measures listed below will slow progress of the disease but will not prevent
it.
1. Control weeds in the area surrounding squash plantings.
2. Control early-season aphids.
3. Isolate squash plantings from one another if possible
4. Clean equipment before moving into a healthy field. Try to allow picker
to obtain clean clothes before entering healthy fields.
5. If plants are not touching, roguing scattered early infections may be
helpful.
6. `Multipick' is resistant to WMV II.
______________________________________________________________________________
______________________________________________________________________________
---------------------------------------------------
---------------------------------------------------
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.
---------------------------------------------------