From: Brian Lo Newsgroups: rec.gardens Subject: FAQ: Cucumbers (Slicing and Markets) Date: Wed, 1 Mar 1995 14:54:53 -0800 CUCUMBER for FRESH MARKET Cucumis sativus (See also file on cucumbers for pickling) Many excellent cucumbers are available. Flowers may be monoecious (separate male and female flowers on the same plant) and gynoecious (plants with only female flowers) and predominantly female (PF) types. There are also parthenocarpic types (also referred to as burpless or seedless), they need no pollination. They are also gynoecious or PF. Parthe- nocarpic or PF types may actually become culls when pollinated since pollina- tion causes seed to develop and produce misshaped fruit. Most commercial field-grown cucumbers are monoecious or gynoecious. With gynoecious varieties seed of a monoecious type is mixed in the seed package to provide a percentage of plants with male flowers for pollination. Parthenocarpic and PF types are most commonly used for greenhouse production. With parthenocarpic types bee colonies need not be used. VARIETIES (approximately 65-75 days to first harvest). Slicing: Dasher II, Gemini, Marketmore 80, Slicemaster, Pacer, Sprint, Triumph, Victory. For trial: Speedway, Turbo, Burpless Bush, and Fanfare (All America, semidwarf, multiple disease tolerance). Burpless (European) type: Tasty Green, Sweet Slice - grow these on trellis for straight fruit. Parthenocarpic type (do not need bees for pollination): Sweet Success, Euro-American, grow on plastic mulch with row covers for earliest production or on trellis for straight fruit). Ethnic markets - Mediterranean: Amira (middle east type, bright green smooth skin, mild flavor); Armenian cucumber (Cucumis melo also called snake melon, snake cucumber, and uri) bright green, deeply ridged fruit which can reach 2 1/2 to 3 feet in length and 2-3 inches in diameter. Oriental: Tasty Green, Tasty Gift, Tasty Time, Green King, Green Gem, Southern Delight, Soarer, Tokyo Slicer, Green Knight (all previous listed are 12" to 15" long and 1 1/2" to 2" in diameter, "burpless"), also Yamato Extra Long (18-24 inch smooth-skinned, dark green "burpless"). Greenhouse: Seedless (parthenocarpic) types: Corona, Farbio, Femspot, Pepinex 69, Primio (all female). Bees must be excluded from the production area, especially when using the predominantly female (pf) types such as Toska. Regular Types: Any of the cultivars mentioned in the slicing category above may be used. These field cucumbers require the introduction of beehives in the greenhouse for proper pollination and fruit set. Novelty: African Horned Cucumber (Kiwano), orange-fruited spiny spe- cialty vegetable. SEED COMPANIES Abbott & Cobb Inc. POB F307, Feasterville, PA 19047 Asgrow Seed Company, POB 5038, Salinas CA 93915 De Ruiter Seeds Inc. POB 20228, Columbus, Ohio 43220 Elsoms Seeds Ltd. Spalding, Lincolnshire, England PE11 1QG Enza Seeds POB 7, 1600AA, Enkhuisen, The Netherlands Ferry-Morse Seed Co. POB 4938, 555 Codoni Ave. Modesto, CA 95352 Harris Moran Seed Co. 3670 Buffalo Rd. Rochester, NY 14624 Nunhems Zaden, Canners Seed Corp. 221 E. Main St. Lewisville, ID 83431 Petoseed Co. Inc. POB 4206, Saticoy, CA 93303 Rijk Zwaan POB 40 2678 ZG DeLier, The Netherlands Seedless Unlimited, RR2 Townline Rd. Leamington Ontario, Canada N8H 3V5 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 SOILS Cucumbers can be grown on a wide range of soils if the soils are well drained and have about 2-3% organic matter, and a high level of fertility. Irrigation is essential to maintain good soil moisture and to obtain high quality fruit. Avoid heavy soils or those easily compacted. Use a soil test to determine the nutrient status and pH of the soil. TEMPERATURE Recent research indicates that a temperature range of 86-90 F. is necessary for optimum cucumber growth. The minimum soil temperature required for germination of this crop is 60 F. with the optimum range between 70 and 95 F. Cucumbers are sensitive to cool soil conditions. Under such conditions, damping-off can seriously reduce stands, and seedling growth may be very slow. SEED AND SEED TREATMENT Cucumber seed numbers approximately 17,600 per pound. Use treated seed. Cucumbers can be particularly sensitive to damping-off problems. Seed treat- ments can dramatically improve stands. Advances in seed priming and film coating have been shown to improve stand establishment under stress condi- tions. Consult your seed dealer about the availability of primed seed. SEEDING AND TRANSPLANTING Slicing cucumbers are planted or set in the field from early May through June. With the availability of the less costly plug transplants, there has been an increasing interest in transplanting. For direct seeding use 2-3 lb. seed/acre if seeding is to be done with- out the use of a precision seeder. Precision seeding is highly recommended, allowing planting to a stand of 7000 to 8000 plants per acre and reducing seeding rate to about 3/4 lb. to 1 lb per acre. For transplant production, slicing cucumber varieties are usually started in individual containers in sterile media in greenhouses 3 to 4 weeks before transplanting outdoors. Do not transplant until all danger of frost has passed. SPACING Thin direct-seeded plantings of slicing cucumbers, or set transplants to a spacing of 8-12 inches within the row, and 48-72 inches between rows. WINDBREAKS Windbreaks are often overlooked as a crop protection aid. In general, close windbreaks, even between every row, give the best wind protection and may moderate the crop micro-climate enough to promote faster plant growth. Where winter cover crops have been employed, it would be a good practice to leave strips of the cover crop as windbreaks. In this case, the strips for the plant beds can be prepared by rototilling, leaving windbreak strips between the plant rows. Establishment of a windbreak crop in the previous fall will insure enough growth to become effective as a windbreak by spring planting time. Seed grain thickly, 2-3 seeds per inch. This requires about 10 lbs. of barley, 9 lbs. of wheat, or 8 lbs. of rye to seed grain rows 12 feet apart. Spring grains such as barley may be useful if planted in February in eastern Oregon. Windbreaks can be removed by mowing, tilling, or an appropriate herb- icide once their useful life is over. FERTILIZER Good management practices are essential if optimum fertilizer responses are to be realized. These practices include use of recommended varieties, selection of adapted soils, weed control, disease and insect control, good seed bed preparation, proper seeding methods, and timely harvest. Because of the influence of soil type, climatic conditions, and other cultural practices, crop response from fertilizer may not always be accurately predicted. Soil test results, field experience, and knowledge of specific crop requirements help determine the nutrients needed and the rate of applica- tion. The fertilizer program should insure adequate levels of all nutrients. Optimum fertilization is essential for top quality, yields, and returns. Recommended soil sampling procedures should be followed in order to estimate fertilizer needs. The OSU Extension Service agent in your county can provide you with soil sampling instructions and soil sample bags and informa- tion sheets. Recommendations are based on a row spacing of 60". With decreased row spacings fertilizer rates should be increased. Western Oregon: NITROGEN (N) When available, apply 10 Tons of manure per acre. Use 80 to 150 lb N/A, with the lower rates of N being applied when legumes were grown the preceding year or a green manure crop is incorporated into the soil prior to planting. Apply one-half the nitrogen at or just prior to planting and the rest when vines begin to "run". Exercise care in nitrogen fertilization. Excess nitrogen may result in viney plant growth which interferes with bee pollination and harvest, and promotes foliar and fruit diseases, resulting in reduced fruit set. Cucumbers are sensitive to fertilizer burn. If the application of N plus potash (K2 O) exceeds 50 lb/A, there is danger of seedling injury from the fertilizer if it is all banded at planting time. There is less danger if the band application is split into two bands. The danger is aggravated as the band comes closer to the seed, and is greater with sandy than with finer textured soil. Immediate irrigation at the first sign of burn should reduce further injury. There is more possibility of damage to seedlings on acid soils where the pH is below 5.5. PHOSPHORUS (P) Phosphorus fertilizer should be banded at planting for vigorous early seedling growth. Bands should be located 2" to the side and 2" below the seed. If the OSU soil test Apply this amount of for P reads (ppm): phosphate (P2 O5 (lb/A): 0 to 15 120-150 l5 to 60 90-120 over 60 60-90 In some areas, a diluted phosphoric acid solution sprayed in a 1-2 inch wide band directly over the seed row has shown to reduce crusting, improve phosphorus nutrition of the crop and increase yield. The benefit of this treatment would be most likely to occur with early plantings on cool soils. POTASSIUM (K) Potassium for both hand and machine harvested fields should be applied before planting or banded at planting time. Amounts above 40 lb K2 O/A should be broadcast and worked into the seedbed. See statements on fertilizer banding under "NITROGEN". If the OSU soil test Apply this amount of for P reads (ppm): potash K2 O (lb/A): 0 to 75 100-150 75 to 150 60-100 150 to 200 40-60 over 200 0 SULFUR (S) Include 20-30 lb S/A in the annual fertilizer program for vine crops. S is sometimes contained in fertilizers used to supply other nutrients such as N, P, and K but may not be present in sufficient quantity. Plants absorb S in the form of sulfate. Fertilizer materials supply sulfur in the form of sulfate and elemental S. Elemental S must convert to sulfate in the soil before the S becomes avail able to plants. The con- version of elemental S to sulfate is usually rapid for fine ground (less than 40 mesh) material in warm moist soil. Sulfur in the sulfate form can be applied at planting time. Some S fertilizer materials such as elemental S and ammonium sulfate have an aci- difying effect on soil. MAGNESIUM (Mg) When the soil test value is below 1.5 meq Mg/100g of soil or when calcium (Ca) is ten times more than the Mg, apply 10-15 lb Mg/A banded at planting. If Mg deficiency symptoms appear, spray with 10 lb Epsom salts in 100 gals of water/A. Magnesium can also be supplied in dolomite, which is a liming material and will reduce soil acidity. Dolomite should be incorporated into the seedbed at the rate of 1-1 1/2 T/A. BORON (B) In general, boron deficiencies are uncommon. If the soil test value for B is less than 1 ppm, an application of 3 lb B/A is suggested. Boron should be applied uniformly to the field as a spray or broadcast. Never band B fertilizer. ZINC (Zn) Zinc deficiencies are uncommon in Willamette Valley soils. When the soil test is below 1 ppm Zn, a response to Zn is expected and 4 lb Zn/A should be included in the fertilizer band. LIME Experimental work has shown that vine crops will produce good yields over a fairly wide range of soil acidity. Lime applications are suggested when the soil pH is 5.6 or below, or when calcium (Ca) levels are below 5 meq Ca/100g of soil. Optimum pH is between 5.8 and 7.0. The rate of lime application can be estimated from the following OSU SMP buffer table. If the OSU SMP buffer Apply this amount of test for lime reads: lime (T/A): Below 5.2 4-5 5.2 - 5.6 3-4 5.6 - 5.9 2-3 5.9 - 6.2 1-2 The liming rate is based on 100-score lime. Lime should be mixed into the soil at least several weeks before plan- ting. A lime application is effective over several years. Some soils may have a fairly high OSU SMP buffer value (over 6.5) and a low pH (below 5.5). This condition can be caused by the application of acidifying fertilizer. In this case the low pH value is temporary and the pH of the soil will increase as the fertilizer completes its reaction with the soil. This temporary "active" acidity from fertilizer is encountered follow- ing recent applications of most N fertilizer materials. Acidifying fertiliz- ers also have a "long term" acidifying effect on soil which is cumulative and leads to lower OSU SMP buffer readings. Sandy soils to which fertilizers have not been recently applied some- times record low pH and high SMP buffer values. In such cases, a light application of 1-2 T/A of lime should suffice to neutralize soil acidity. For acid soils low in Mg (less than 0.8 meq Mg/100g of soil), 1 T/A of dolomite lime can be used as a Mg source. Dolomite and ground lime stone have about the same ability to neutralize soil acidity. The possibility of seedling injury from the band application of ferti- lizer is less when the soil pH is 5.6 or above. Some Willamette Valley experiments have shown decreased uptake of phosphorus from band applications of phosphorus when the pH approaches 5.5. Lime applications should be broadcast, preferably in the fall, and incorporated into the seedbed. Do not plow lime down leaving the surface soil unlimed. Fertilizer Guide #2, "Liming Materials for Oregon", which is available from your local OSU Extension Office, provides additional information lime. Eastern Oregon: At time of seeding or transplanting, band the following: Nitrogen: 80-150 lbs. nitrogen/acre. Apply two-thirds of this during the last half of the crops growth, with the first side-dress at the time the vines begin to runner. Phosphate: 100-150 (P205) lb/acre Potash: 50-70 (K20) lb/acre Where mulching and trickle irrigation are practiced nitrogen can be fed through the trickle irrigation system at 20 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. These fertilizer recommendations are based on research conducted by OSU Horticulture and Soils Department and Extension faculty, and are quoted from OSU Fertilizer Guide FG 68. FLOWERING AND POLLINATION Depending on cultivar, cucumbers plants may bear separate male and female flowers on the same plant (monoecious), only female flowers (gyno- ecious), or male flowers and perfect flowers (male and female organs in the same flower) i.e. andromonoecious. Most modern cultivars have plants that bear only female flowers (gynoecious), so seeds of plants that are monoecious (bearing separate male and female flowers on the same plant) are mixed into the seed lot (usually 10 to 15%) to allow pollination. These seeds are usually dyed a different color from the seeds of the cultivar being planted. Bees are needed to transfer pollen from the male flowers to the female flowers, thus making fruit set possible. Cucumbers are not pollinated by wind. It is recommended that 1-2 honey bee colonies of 30,000 to 50,000 bees each be introduced for every acre during the blooming period. Naturally occurring bee populations are not considered to be adequate since their presence may not coincide with the full blooming period, or their numbers may be too low. Information from the midwest indicates that cucumbers require at least 15 bee visits to each flower for normal pollination and fruit set, and maximum yields, although some of the new all-female varieties may set as much as one-third of their yield without being pollinated. Hives should be placed at the edge of the field after the first blooms are visible so that no point in the field is more than 200-300 yards away from a colony. Placing bees prior to flowering may result in the bees establishing themselves on nearby crops thus reducing their effectiveness in cucumber pollination. Research indicates that total yield increases resulting from good bee management can range from 25 to 50 percent. PLASTIC GROUND MULCHES AND ROW COVERS Use of plastic mulch and trickle irrigation has been shown to be very effective with both transplanted and direct seeded slicing cucumbers. Early and total yields are increased and more than compensate for the increased cost. 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 important. Spunbonded polyester and polypropylene, and perforated polyethylene row covers may be used for 4 to 8 weeks immediately after seeding or transplant- ing. Covers should be removed when plants begin to flower to allow proper pollination by insects. 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. SOIL SUPPORTED COVERS Preliminary research in California indicates that soil supported covers or mini-tunnels have been used to promote early production of tomatoes, at a minimum of cost. This technology would have similar application in a number of other crops. Similar to hoop supported tunnels, these increase soil and air temperature around the plants, maintain surface soil moisture, and prevent crusting. They may also provide about 7 days advantage in earliness and har- vest season, depending on crop and time of planting. Soil to form the sides of the tunnel is brought from the sides of the plant row which may be direct seeded or transplanted at the same time, or prior to tunnel installation. A modified bedshaper is used to form a ridge on each side of the plant row, leaving a suitable area for planting. A 36 inch wide piece of embossed clear plastic is then used to cover the plant row, leaving a 5 to 6 inch high space between the planted row and the plastic cover. It is estimated that temperatures may be increased 10-20 F. depending on time of planting and sunlight availability and intensity. IRRIGATION Irrigation requirements depend on the length of harvest. Some fields may be hand harvested 10-12 times and need to be kept growing adequately. Ten to fifteen inches of water may be required depending on seasonal variation and variety. Irrigations need to be coordinated with picking schedules. 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. HARVESTING AND HANDLING Slicing cucumbers are generally harvested in western Oregon from mid July through September, however, weather permitting, they can be harvested well into October. East of the Cascades, harvest may begin about 2 weeks earlier. Approximate yields of fresh market (slicing) cucumbers are 115 cwt./acre with good yields about 250 cwt./acre. For highest returns, thoroughly harvest marketable fruit at regular intervals. Remove oversize fruit so later fruit can develop properly. During warm weather conditions, cucumbers may grow very rapidly and it is important to shorten harvest intervals. STORAGE (Quoted from USDA Ag. Handbook #66): Cucumbers can be held 10 to 14 days at 50 to 55 F with a relative humi- dity 90-95%. They are subject to chilling injury if held longer than about 2 days at temperatures below 50 F. At temperatures of 50 f and above, they ripen rather rapidly, the green color changing to yellow. This color change starts in about 10 days at 50 F and is accelerated if the cucumbers are stored in the same room with apples, tomatoes, or other ethylene-producing crops. Modified atmospheres, particularly with low oxygen (5 %), will retard yellow- ing. Cucumbers are vary susceptible to shriveling; hence, the humidity in the storage should be kept high. Cucumbers for the fresh market are usually waxed to reduce moisture loss. Shrink-wrapping with polyethylene film can also delay the loss of turgidity. Symptoms of chilling injury are water-soaked spots, pitting, or tissue collapse. A surge in ethylene production may occur and extensive decay will develop when chilled cucumbers are removed from low-temperature storage. PACKAGING Slicing cucumbers are commonly packaged in 55 lb. l-l/9 bushel cartons and wirebound crates; 47-55 lb. bushel cartons and wirebound crates; 26-32 lb. cartons, or 28-32 lb. L. A. lugs. PEST CONTROL FOR CUCUMBER 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. ______________________________________________________________________________ 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 horticult- ural 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 vermiculite. 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. 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 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 pre-emergence 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). ------------------------------------------------------------------------ bensulide + 4 to 6 lb naptalam + Prefar + Alanap 2 to 4 lb ai/A Note inforamtion above for bensulide and below for naptalam. Use lower rates on sandy soils. ______________________________________________________________________________ PREEMERGENCE Weed Treatment Active Ingredient Per Acre and Application Comments ------------------------------------------------------------------------------ naptalam 3 to 4 lb ai/A Alanap Apply immediately after seeding to moist soil and sprinkler irrigate with 0.5 to 1 inch water or mechanically incorporate in 1 to 1.5 inches soil with spiketooth harrow to place herbicide in germination zone. Use lower rates on sandy soils. Controls primarily broadleaf weeds. (Reverses geotropism in roots). ------------------------------------------------------------------------ ethalfluralin 1.12 to 1.69 lb ai/A Curbit Adjust rates depending on soil 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 improve leaf absorption. Erratic control often occurs when grasses are stunted or stressed from drought, high temperatures, or low fertility. Resis- tant 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 production, cell membranes, and new growth.) ______________________________________________________________________________ POSTEMERGENCE LAY-BY TREATMENTS Weed Treatment Active Ingredient Per Acre and Application Comments ------------------------------------------------------------------------------ trifluralin 0.5 to 0.75 lb ai/A Treflan Apply as a directed spray between rows when crop has 3 to 4 true leaves and incorporate 2 to 3 inches deep, using rolling cultivators set to throw soil towards plants in the row. Spray only 1 time per year. Consult label for restrictions on planting sensitive crops within 12 months. Possible injury may result in cool soils and from carryover from repeated use without adequate rotation. (Inhibits mitosis, primarily in shoots). ------------------------------------------------------------------------ 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 re- strictions 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 and Washington. 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 ap- plication. 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 FOR CURRENTLY LEGAL REGISTRATIONS, RATES AND COMPLETE INSTRUCTIONS. Insect and Description Control, Active Ingredient Per Acre --------------------------------------------------------------------------- Aphids, including diazinon - 0.5 lb spray Bean aphid Aphis fabae malathion - 1.25 lb Dull black plant louse that colo- Phosdrin - 0.25 lb nizes during latter part of the season. Pyrellin - 1 to 2 pt Melon aphid Dibrom - 1 lb Aphis gossypii Metasystox-R - 0.5 lb Small plant louse, yellowish to dark green in color. Pale forms endosulfan - 0.5 to 1.0 lb have dark mottling. Colonize plants late in the season. NOTE: Bees are important in cross pollination of cucumbers. Take Potato aphid precautions to avoid poisoning Macrosiphum euphorbiae them. See; "How to Reduce Poisoning of Bees from Pesti- Green to pinkish plant louse that cides." colonizes plants. Transmits virus. --------------------------------------------------------------------------- Cucumber beetles methoxychlor - 1 to 3 lb Small, slender, greenish-yel- diazinon 0.5 lb low beetles with three promi- nent black stripes on back. At- malathion - 1 to 1.5 lb tack young plants. Larvae feed on roots and underground carbaryl - 1 lb parts of stems. Dibrom - 1 lb OR Yellowish-green, black-spotted endosulfan - 0.5 to 1 lb beetle, common to western Oregon and southwestern Guthion - 0.5 lb Washington. Damage usually limited to young plants. Asana - 0.03 to 0.05 lb Lannate - 0.45 to 0.9 lb Pyrellin - 1 to 2 pt --------------------------------------------------------------------------- Cutworms Lannate - 0.45 to 0.9 lb Many species Asana - 0.03 to 0.05 lb Small to large larvae that feed on foliage and stems. Sevin bait 5% pellets - 1 lb --------------------------------------------------------------------------- Cabbage looper Lannate - 0.45 to 0.9 lb Trichoplusia ni Dibrom - 1 to 2 lb Pale green larvae with white stripes. Move in looping manner. Asana - 0.025 to 0.05 lb --------------------------------------------------------------------------- Grasshoppers Asana - 0.03 to 0.05 lb Different species Nosema locustae - use as manufacturer directs --------------------------------------------------------------------------- Seed corn maggot Seed Treatment Delia platura Lorsban 50 SL - 1 oz ai/100 lb of seed. Small legless maggot that feeds on and destroys germinating seeds. --------------------------------------------------------------------------- Slugs metaldehyde baits. Do not contami- nate edible plant parts. --------------------------------------------------------------------------- Spider mites Kelthane 35W - 0.6 lb Do not Tetranychus spp. feed or use EC formulations. Tiny spiderlike animals that malathion - 1 to 1.9 lb feed on plant juices causing leaves to turn yellow and die. Metasystox-R - 0.5 lb Phosdrin - 0.5 lb Dibrom - 1 lb --------------------------------------------------------------------------- Garden symphylan Telone II or C-17 preplant Scutigerella immaculata Small, white, centipede-like animals in soil. -------------------------------------------------------------------------- Thrips diazinon - 0.5 lb spray Very small, slender insects. Dibrom - 1 lb Pale green (young) to black (adults). Feed on leaf surfaces. Surface feeding causes leaves to appear silvery. --------------------------------------------------------------------------- Wireworms diazinon - 3 to 4 lb active Limonius spp. ingredient per acre. Broadcast granules or emulsifiable Brown, jointed larvae of click formulations 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 --------------------------------------------------------------------------- --------------------------------------------------------------------------- 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. CUCUMBER -- ALTERNARIA LEAF SPOT (Fungus Leaf Spot) Cause: A fungus, Ulocladium consortiole. Recent work in Washington has shown this disease does not reduce yields under Washington conditions. Symptoms: Small tan spots which turn dark brown on maturing. Often concentric rings may be noticed in the older spots giving them a "bull's-eye" appearance. Coalescing spots may involve large areas of the leaf. Under Northwest condi- tions the fruit have not been attacked by this organism. ~Control: Use one of the following sprays: 1. Bravo 720 at 2 to 3 pt/A in water to cover. May be applied by sprinkler (see product label). 2. Mancozeb at 1.8 to 2.4 lb ai/A. Do not apply within 5 days of harvest. 3. Maneb at 1.2 to 1.6 lb ai/A. Do not apply within 5 days of harvest. --------------------------------------------------------------------------- CUCUMBER -- ANGULAR LEAF SPOT Cause: Pseudomonas syringae pv. lachrymans lacrymans, a bacterium. The bacterium overwinters in diseased plant material and on the seed. It is spread by rain, sprinkle irrigation, or on hands and clothing of workers. In recent years the incidence of the disease has been reduced by the use of tolerant varieties. Symptoms: Leaves, stems, and fruits may be affected. The leaf spot is irregu- lar in shape, angular, with a water-soaked appearance. Bacteria may ooze from the spots in droplets which dry to a white residue. The water-soaked area later turns gray and dies. Often the dead tissue is torn away from the healthy portion of the leaf leaving large irregular holes. The water-soaked spots on the fruits are smaller and circular. Lesions are usually superficial, but the injury may permit the entrance of soft-rot organisms. The affected tissue becomes white and may crack open. ~Control: The following control program is a combination of those used in other areas. 1. Plant resistant varieties. Pickling varieties `Regal', `Royal', `Calypso', `Pioneer', `Express', `Cross Country', and `Frontier', have shown tolerance under Washington and Oregon conditions. The use of these varieties is usually sufficient under our conditions. The slicing varieties `Victory', `Bel Aire', `Raider', `Encore', `Poinsett 76', `Slice Nice', `Dasher II', `Turbo', `Quest', and `Sprint-N' are resistant. 2. Stay out of wet, infected fields. 3. Application of fixed copper spray has reduced the spread of the diesase, but copper sprays have been reported to cause some stunting and leaf chlorosis in Oregon. Several copper materials are available. Residues: Arasan--considered to be a nonfood use. Captan--seed treatment, considered a nonfood use. Coppers--exempt. --------------------------------------------------------------------------- CUCUMBER -- BACTERIAL WILT Cause: Erwinia tracheiphila, a bacterium, which overwinters in the bodies of the striped and 12-spotted cucumber beetles. In Oregon, the disease occurs on cucumbers occasionally. The bacterium affects only plants belonging to the cucumber family--cucumbers, muskmelons, pumpkins, squashes, gherkins, white gourds, and a number of wild plants. There is a very close relationship between the bacterium and the beetles--if the beetles are eliminated so is the bacterium. The bacterium hibernates in the digestive tract of a few beetles and in the spring finds its way through the feces of the carriers to the young plant. It can enter the plant tissue only through deep wounds such as injuries produced by feeding beetles, or later in the season, following grasshopper invasion. The bacteria are not carried in or on the seed. When beetles chew on affected leaves, which they seem to prefer, their mouth parts become contaminated with the bacteria, which are carried to the next three or four plants on which the beetle feeds. Infection takes place only when there is a film of water sufficient for the pathogen to reach the wound in the inner leaf tissue. The beetles do not migrate in rainy periods; the disease rarely is found where the annual rainfall is over 45 inches or below 18 inches. Optimum average daily temperatures for development of the disease are 52o to 60o F. Symptoms: General wilting of the plant. Infection begins on one or a few leaves which droop suddenly. The disease spreads from the foliage downward into the petioles and stems until the plant has wilted and died. The fruit also wilts and shrivels. ~Control: Spraying or dusting to control the carrier beetles is effective. See Pacific Northwest Insect Control Handbook. --------------------------------------------------------------------------- CUCUMBER -- CURLY TOP Cause: A virus disease spread by the beet leafhopper and surviving from year to year in perennial weed hosts. Symptoms: Growth is retarded and the older leaves take on a tan-yellow color. Terminal leaves are sometimes darker than normal, and the entire plant is stunted. The few fruits produced are small, of poor quality, and abnormally shaped. ~Control: 1. Set out more plants than needed and remove diseased plants as soon as they can be detected. 2. Partial shading will discourage movement of the leafhopper vector onto the plants, thus reducing the possibility of infection. 3. There are no known resistant varieties. --------------------------------------------------------------------------- CUCUMBER -- DAMPING-OFF Cause: This disease is caused by the fungus Pythium ultimum, which lives in the soil. It attacks seedlings of many different crops. Symptoms: Seedlings may be attacked before they emerge or after they are up, resulting in gaps and uneven stands. Young plants suddenly wilt and topple over. Water-soaked lesions are apparent on the stems at the soil line. As the seedlings mature, they become resistant to attack. The disease can be a serious problem in cool, wet soils. ~Control: 1. Delay planting until soil warms so as to increase seedling growth and emergence. 2. Mulch soil to increase soil temperature. 3. Plant shallow to promote quick emergence and growth. 4. Treat seed with captan. 5. Treat seed with Apron FL 1.5 fl oz/cwt (Pacific Northwest states only). 6. Treat seed bed with Ridomil 2E Broadcast: Apply 4 to 8 pt Ridomil 2E/treated A at planting in 20 to 50 gal of water. Banded: Apply Ridomil 2E in a 7-inch band. Rates are calculated based on row spacing and plant density according to the label. Broadcast and incorporated: Apply 4 to 8 pt of Ridomil 2E/A as a broadcast soil application in 20 to 50 gal of water and incorporate in the top 2 inches of the soil. If beds are used, broadcast and incorporate prior to bedding. Seed treatment: Apply Anchor at 1.502/cwt seed. --------------------------------------------------------------------------- CUCUMBER -- GUMMY STEM BLIGHT See Squash--Black Rot or Gummy Stem Blight --------------------------------------------------------------------------- CUCUMBER -- MOSAIC Cause: A virus disease spread by aphids and possibly cucumber beetles. The virus overwinters in the seed of wild cucumber and in wild perennial milkweed, ground cherry, and matrimonial vine. Symptoms: Leaves are markedly mottled and wrinkled with yellow and green blotches and edges cupped downward. Early season infection results in dwarfing of the plants while later infections show the typical mosaic symptoms only on later season growth following infection. The fruit develops raised wartlike bumps with pale, whitish-green areas between, and has a bitter taste. Some varieties of small, later fruits have a pale greenish-white appearance. ~Control: 1. Remove all infected vines. 2. Remove wild cucumber vines, milkweed, and other susceptible weed hosts to within 1,000 feet of the field if possible. 3. Control aphids by spraying or dusting. 4. In slicing cucumber varieties, `Niagara' is resistant. There is also some tolerance to the virus in the following hybrids--`Burpee', `Surecrop', `Gemini', `Marketmore', and `Sensation'. For pickling cucumbers, the varieties `MR-17', `SMR-18', `SMR-58', and `Pioneer' have high tolerance and are recommended for planting. --------------------------------------------------------------------------- CUCUMBER -- NEMATODE (Root-Knot) See Tomato--Nematode (Root-Knot) for a further description of cause and symptoms. ~Control: Mocap 10E (20 lb/A) or Mocap EC (1 to 1.5 qt/A) in a band 12 to 15 inches wide on the row at or just before planting. Do not use a seed furrow treatment. --------------------------------------------------------------------------- CUCUMBER -- POWDERY MILDEW Cause: A fungus, Erysiphe cichoracearum. Symptoms: At first tiny, white superficial spots appear on the leaves and stem. The spots become powdery white and expand to cover all portions of the plant. Sometimes the mycelium becomes covered with small black spots about the size of a pinhead. Usually the disease occurs in scattered spots in the field. ~Control: A 2-year rotation out of cucurbits is helpful. The varieties `Dasher II', `Turbo', `Calypso', `Cross Country', `Flurry', `Royal', `Regal', `Quest', `Cherokee', `Marketmore', and `Pioneer' are resistant to powdery mildew. Usually the disease is not severe enough to warrant a spray program. Under greenhouse conditions sulfur dust, Benlate, or wettable sulfur will control the disease. CAUTION-- Sulfur can cause injury to cucumbers, especially when temperature exceeds 85 F. Benlate may be used as a field spray. Benlate Warning: Resistant strains of many fungus pathogens have become troublesome when Benlate is used exclusively in a spray schedule. To reduce the possibility of Benlate resistance, alternate Benlate sprays with sprays of non-benzimitazole fungicides. Field Spray -- Bayleton 50 WP or 50 DF. Apply 2 to 4 oz/A in a minimum of 10 gal of water by ground or 5 gal of water by air. Begin when disease first appears and repeat at 14-day intervals. Do not apply more than 16 oz of Bayleton 50 WP or 50 DF per season. Bayleton will not give control of Sphaeroteca fuliginea. Residues: Benlate--0.125 to .250 lb ai/A ground application only. Tolerance 1.0 ppm. Limitation 0.250 lb ai/A. No time limits. --------------------------------------------------------------------------- CUCUMBER -- ROOT ROT See Squash--Root Rot. --------------------------------------------------------------------------- CUCUMBER -- SCAB Cause: A 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 inch in diameter. The canker gradually grows darker and the tissue collapses further into the cucumber until a pronounced cavity is formed, which is lined with a dark-green velvety layer of the fruiting fungus. The first symptom on 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: Use resistant varieties whenever available. Scab-resistant varieties have been developed and include `Dasher II', `Raider', `Encore', `Sprint', `Poinsett 76', `Turbo', `REgal', `Flurry', `Calypso', `Quest', `Gemini', `Marketmore', `Pioneer', `SMR-58', and `SMR-18'. Commercial growers should consult processors for the resistant varieties to be grown. Spray -- 2 to 3 pt. of Bravo 720. Bravo may be applied through overhead irrigation. See label for directions. --------------------------------------------------------------------------- CUCUMBER -- SEED TREATMENT Aids in control of seed decay and damping-off. Thiram--0.75 of 50 percent material/lb of seed. Do not apply more than 2.25 oz actual/100 lb of seed (dry or slurry). Considered to be a nonfood use. Captan .7 to 1.6 oz ai (slurry) or 1.5 to 2.25 oz ai (dry)/100 lb of seed. Considered to be a nonfood use. Apron FL 1.5 fl oz/cwt seed. Anchor at 1.5 fl oz/cwt seed. --------------------------------------------------------------------------- CUCUMBER -- WHITE MOLD Cause: Sclerotinia sclerotiorum, a fungus. White mold is a widespread but relatively unimportant disease of cucumbers grown in the field, but it has caused severe losses of vines and fruit grown in greenhouses. Symptoms: This disease occurs primarily as a stem blight or as a fruit rot. Older vines are most often affected. Following the development of the white cottony mold, the stem dries and becomes withered, and the small sclerotia appear in the rotting tissues. Cucumber fruits affected are watery, soft, and later develop sclerotia. ~Control: 1. Rotate crops and deep plow to bury sclerotia. 2. Remove infected vines and fruit from the field and destroy. ______________________________________________________________________________ ______________________________________________________________________________ --------------------------------------------------- --------------------------------------------------- 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. --------------------------------------------------- ---------------------------------------------------