From: Brian Lo Newsgroups: rec.gardens Subject: FAQ: Peppers Date: Wed, 1 Mar 1995 09:10:47 -0800 PEPPERS Capsicum annuum and C. frutescens Taxonomists have only recently begun to agree regarding classification of the domesticated species of Capsicum. Although 5 species are described, only two, C. annuum and C. frutescens have any significance commercially in the U.S.A. Early species separation on the basis of fruit shape, color and position are of little taxonomic value. Flower and seed color, shape of the calyx, the number of flowers per node and their orientation, are the primary separating characteristics. C. annuum is the most important domesticated species in the U.S.A. and is the species to which all bell peppers, and all the peppers listed below belong (unless specified otherwise.) The only C. frutescens pepper of any significance is Tabasco. The Tabasco pepper is difficult to cross with C. annuum types. Hot peppers may belong to any of above species and others. The C. chinense varieties Habanero and Scotch Bonnet are considered the hottest. See other comments under "Novelty" pepper section below. The interest in peppers extends to their nutritive and medicinal value in that peppers are a recognized source of Vitamins C, E and are high in antioxidants. These compounds are associated with chemoprevention of cardio- vascular disorders, cancers, and cataracts. Peppers are a warm-season crop and need a long season for maximum production. Temperature has a large effect on the rate of plant and fruit growth and the development and quality of the red or yellow pigments. Ideal temperature for red pigment development is between 65 and 75 F. Above this range the red color becomes yellowish, and below it color development slows dramatically and stops completely below 55 F. Many excellent pepper varieties are available. Test several and select the ones that do well under your production system, and meets your market needs. PUNGENCY RATINGS The most common sensory method to determine pungency in peppers has been an organoleptic test (Scoville, a dilution-taste procedure) with results ex- pressed as Scoville Heat Units (SHU). The validity and accuracy of it have been widely criticized. The American Spice Trade Association and the Interna- tional Organization for Standardization have adopted a modified version. The American Society for Testing and Materials is considering other organoleptic tests (the Gillett method) and a number of chemical tests to assay for capsai- cinoids involved in pungency. Still, the values obtained by the various tests are often related to Scoville Heat Units. A "National Fiery Foods Show" is held annually in Albuquerque NM. For more information call 505/873-2187. RECOMMENDED BELL PEPPER VARIETIES (approximately 60-70 days to first harvest from transplants): Bell (green): Belle Star, Yankee Bell, Bell King, North Star, Wonder Bell, Lady Bell, Jupiter Elite, Park's Early Thickset, Bell Tower, Skipper, Bellboy, Mission Bell, Ringer, Bell Captain, Melody, Ace Hybrid, Cardinal. Research in the Hermiston area indicates that Jupiter Elite, Bell Tower, Belmont, Galaxy and Skipper performed well. For trial: Camelot, Inia, Merlin, Ranger, Summersweet, Wonderbelle, Cubico. Note: In 1992, Bell Star and Yankee Bell produced the highest proportion of 4-lobed, blocky peppers. Their plant growth is more open, and not as many peppers were misshaped by growing among branches and being confined between other fruit. Bell (Red): Many green bell peppers turn red when fully mature. How- ever, early, large-fruited, thick-walled varieties, demanded by the market, are rare. Research at O.S.U. and from British Columbia indicates that Lady Bell, La Bamba, Four Corners, Merlin, Ace Hybrid, Bellboy and Cardinal per- formed best. Four Corners and Merlin also had thick-walls. For trial: Bell Star, Melody, North Star, Ringer, Candice, Vidi and Predi. Bell (yellow): Golden Belle and Astro (bright yellow), Klondike Bell (early, high yield, has an some orange tinge), Honey Bell, Golden Cal Wonder, Orobelle (orange-yellow). For trial: Atlantic, Summer Sweet, Marengo (Lamuyo type); Gold Crest (small fruit) and Summer Sweet (both turn yellow or orange- yellow quickly). Bell (orange): Corona (performed best in OSU trials in '92). Oriole (best in trials in British Columbia). For trial: Ariane, Kerala, Ori, Valencia. Purple, chocolate, and white bell peppers (see list below). These are intermediate colors lasting 7-10 days then turning red. Note: Many of the red, yellow and orange peppers found in the market are greenhouse-grown from varieties specially developed for greenhouse production. Bell pepper varieties for greenhouse production of green or red fruit for specialty markets (for trial only): Cubico, Flair, Plutona, Delphin. Yellow fruit: Samantha, Gloden Flame, Golden Belle, Golden Crest, Marengo, Orobelle, Olympic. Orange fruit: Ariane, Valencia. -------------------------------------------------------------------------- Catagory, type of fruit attachment and pungency range: variety name Color Stages Pungency Remarks -------------------------------------------------------------------------- Bell; 3.5"X4.5", fruit pendant, pungency 0-100 Scoville Heat Units (SHU): Bell King green to red sweet early Bell Captain green to red sweet thick walls Bell Tower green to red sweet smooth Bellboy green to red sweet thick wall Bellestar green to red sweet smooth California Wonder 300 green to red sweet late, thick Cardinal green to red sweet thick wall Four Corners green to red sweet good shape Jupiter green to red sweet large, mid Lady Bell green to red sweet early Midway green to red sweet early Mission Belle green to red sweet v. smooth Parks Early Thickset green to red sweet early Parks Whopper green to red sweet med. Pip green to red sweet large Predi green to red sweet large, deep red Ringer green to red sweet large, mid Skipper green to red sweet smooth Sweet Belle green to red sweet mid Goldie yellow to red sweet early Gypsy yellow to red sweet early Yellow Belle yellow to red sweet early Early Bountiful to yellow sweet Golden Summer to yellow sweet late Golden Cal. Wonder to yellow sweet thick wall Golden Bell to yellow sweet early Inia to yellow sweet thick wall Klondike Bell to yellow sweet early, thick wall Orobelle to yellow sweet thick wall Summer Sweet 820 to yellow sweet Golden Crest to orng-yellow sweet Quadrato d'Oro to orng-yellow sweet Ariane to orange sweet large, thick Corona to orange sweet large, thick Kerala to orange sweet large, thick Oriole to orange sweet large, thick Salsa RZ to orange sweet large, thick Super Stuff yellow to orange sweet early Catagory, type of fruit attachment and pungency range. Variety name Color Stages Pungency* Remarks -------------------------------------------------------------------------- Bell peppers continued: Lorelei purple then red sweet small Purple Beauty purple then red sweet small Purple Belle purple then red sweet small Violetta purple then red sweet small Blue Jay to lavender then red sweet Islander to lavender then red sweet Lilac to lavender then red sweet Chocolate Bell to chocolate sweet large fruit Mulato to chocolate Sweet Chocolate to chocolate sweet small fruit Albino to white then red sweet small Dove to white then red sweet small Ivory to white then red sweet Elongated Bell; (lamuyo type fruit) 3.5"x5"; pendant, pungency 0-100 SHU: Blue Star green to red sweet large, late Elisa green to red sweet mid Marengo green to yellow sweet Melody green to red sweet early Signet green to yellow sweet early Other peppers and their descriptions (approximately 65-105 days depending on type). Anaheim; fruit 2"x7"; pendant, pungency 500-3,500 SHU (most 500-1000 SHU): Anaheim TMR green to red mild Anaheim M green to red warm Coronado green to red warm New Mexico 64L green to red mild NuMex Conquistador green to red sweet for paprika Volcano green to red hot Poblano/ancho; fruit heart-shaped 3"-4" x 4"-7"; pendant, 1,000-2,000 SHU. The poblano pepper is a major type grown in Mexico, used green, red or dried (called ancho when dried). It is commonly used for chiles rellenos: Ancho 101 dark green to red mild thick wall Esmeralda dark green to red ditto New Mexican dark green to red ditto Poblano dark green to red warm ditto Verdano dark green to red ditto Catagory, type of fruit attachment and pungency range. variety name Color Stages Pungency* Remarks -------------------------------------------------------------------------- Elongated, tapered; fruit variable shapes and sizes; pendant, 0-1000 SHU: Banana Supreme green to yellow sweet early Canape green to yellow sweet early Cuban yel-grn:red orange warm Cubanelle yel-grn:red orange mild long fruit Hungarian Wax grnish yel:yellow warm Sweet Banana grnish yel:yellow sweet Cherry; about 1" diameter; upright, 100-5,000 SHU: Cascabel green to red hot Large Red Cherry green to red warm Sweet Cherry green to red warm Cayenne; fruit 0.5"x3"; pendant, 30,000-50,000 SHU. A favorite in Creole and Cajun cooking: Cayenne, Large Red Thick green to red firey slender Cayenne continued... Cayenne, Long Slim green to red firey slender Carolina Cayenne green to red firey Charlston Hot grn to orange to red firey to 4" long Super Cayenne green to red firey long slender Jalapeno; fruit 1.5"x3"; pendant, 2,500-5000 SHU. The most common hot chili grown in the U.S.A.: Jalapa green to red hot blunt cylind. Jalapeno M green to red very hot thick wall Jalapeno Hot green to red hot smooth Mitla hybrid green to red hot thick, blunt cyl. Tam Jalapeno #1 green to red hot thick wall Pimento; fruit 1.5"x2.5"; pendant, 0-100 SHU: Pimento L green to red sweet thick wall Serrano; fruit 0.5"x2.25"; pendant, 5,000-10,000 SHU: Serrano types dark green to red very hot small Tabasco C. frutescens; fruit 0.25"x 1.25";pendant, 30,000-50,000 SHU: Tabasco green to red firey small Novelty, ornamental: Marbles (prolific round, mix of green, yellow and red fruit), Riot (prolific upright long fruit, mix of green, yellow and red). Habanero (C. chinense) a firey-hot box-shaped small pepper turning from green to orange. Although the Habanero (C. chinense) pepper has been listed as being the hottest of all peppers, some rated at 200,000 to 300,000 SHU, not all Habaneros are hot! Hot Habanero peppers are used to make hot bottled sauces. They are grown mainly in Central America and the Yucatan. Other C chinense extremely hot peppers include Scotch Bonnet (yellow), and Bahamian. 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, OH 43220 ENZA Zaden, POB 7, 1600 AA, Enkhuisen, Netherlands 02280-15844 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 Nickerson-Zwaan Seed Co. POB 1787, Gilroy, CA 95021 Petoseed Co. Inc. POB 4206, Saticoy, CA 93303 Rogers NK. POB 4727, Boise, ID 83711-4727 Royal Sluis Inc. 1293 Harkins Rd. Salinas, CA 93901 Sluis & Groot of America Inc. 124 Griffin Street, Salinas, CA 93901 Stokes Seeds Inc. POB 548, Buffalo, NY 14240 Sunseeds, 2320 Technology Pkwy. Hollister, CA 95023 The Pepper Gal. POB 12534 Lake Park, FL 33403-0534 Vilmorin Inc. POB 707 Empire, CA 95319 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 Zwaan Seeds Inc. POB 397, Woodstown New Jersey 08098-0397 SOIL Peppers grow best on well-drained, moderately fertile soils. Use a soil test to determine fertilizer and liming requirements. Adjust soil pH to near neutral (7.0) for maximum yields. SEED AND SEED TREATMENT Pepper seed numbers approximately 72,000 per pound, but bell peppers are not normally direct seeded. Use high quality, fungicide treated seed in the production of transplants. Some seed companies now offer "vigorized' or "conditioned" seed which has better germination under cool soil conditions. Peppers are sensitive to damping-off. Most chile and spice peppers are direct-seeded. In direct seeded plantings a pop-up fertilizer solution may be helpful. Spray directly on the seed a solution of 2-6-0 at 1 pint per 100 lineal feet of row (use 1/2 this rate on sandy soils). A 2-6-0 solution is equivalent to 1 part of 10-34-0 liquid fertilizer diluted with 4 parts of water. TEMPERATURE REQUIREMENTS Pepper is a warm-temperature vegetable and requires a long growing sea- son. Transplants which are grown should be kept close to the following tempe- ratures: Days:65-85 F. Nights: 60-65 F. Temperatures above 95 F may result in flower bud drop. Highest yields are obtained when soil temperatures remain in the 70-75 F range. Soil temperatures below 68 F may result in substantial yield reductions. The use of clear plastic mulch applied over herbicide treated soil, or black plastic mulch, or the new IRT (wave-length selective) mulch is strongly recommended. A very few peppers are sometimes grown in greenhouses. The varieties Bellboy, Blue Star and Mogador are reported to tolerate cool temperatures that sometimes occur in off-season greenhouse production. TRANSPLANT PRODUCTION AND TRANSPLANTING It takes between 3 and 4 ounces of seed to produce enough plants for an acre. Seeds should be planted in a heated greenhouse 6 to 8 weeks before the field transplanting date. When growing transplants in unheated greenhouses, cold frames or field transplant beds, 8 to 14 weeks may be necessary. Seedlings are transplanted to other flats when the first true leaves are l l/2 in. long and spaced 2 to 2 l/2 in. apart in the greenhouse or plant bed. At all times handle pepper seedlings with care because they are easily broken or damaged. Harden transplants for about a week before transplanting to the field by reducing moisture and maintaining a temperature of 55 to 65 F. This will give resistance to wilting and sunscald. 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. You will need about 13 fifty gallon batches to transplant an acre. Depth of transplanting has normally been to the top of the roots or root ball. Research from Florida with the variety Jupiter suggests that pepper transplants may benefit from being set deeper, up to the first true leaf. Thirty days after transplanting, plants planted to the first true leaf had more leaves, greater plant dry weight, more blooms and less lodging than transplants planted to the cotyledons or to the top of the root ball. Other data from Pennsylvania suggest caution however. Soil temperature and moisture would be important considerations. Greenhouse peppers are sown October through February for harvest of red fruit approximately 5 months later, March through July. SPACING Space rows, or pairs of rows about 18-36 inches apart. Plants should be 12-l8 in. apart in the row and between pairs of rows, depending on method of transplanting and transplanter capability. These spacings represent a plant population of from 10,000 to 29,000 per acre Leave roadways across the field at about 150 foot intervals to facili- tate carrying pails of peppers to collection locations if a harvester aid and bulk loading is not used. When using plastic mulch, plant 2 rows of peppers per mulch strip, using 36 inch wide platic. Space plastic strips 5-6 feet apart. Use drip irriga- tion tubing under the plastic mulch between the two pepper rows, with drip emmiters at 9 inch spacing down the row. In greenhouse production, allow 3.0 to 3.5 square feet/plant. Plants are pruned to a 2-stem training system. After 10-12 leaves have developed, the plant forks, and a flower develops at the fork. Two or three branches are produced, of which the two strongest are chosen for further production. These must be supported by a string or post, and all subsequent branches removed after the 2nd leaf. Restrict fruit set on the two stems until at least 3 or 4 leaf axils have formed or stem growth and subsequent fruit set will be greatly reduced. FERTILIZER A soil test is the most accurate guide to fertilizer requirements. The following recommendations are general guidelines for loamy soils or when organic matter exceeds 2 1/2% : Nitrogen: 75-100 (N) lb/acre. Side-dress with 35-50 lb/acre of nitrogen after the first flowers are set. Where mulching and trickle irrigation are practiced, additional nitrogen can be fed through the trickle irrigation system at l5 lb./acre when the first fruit begins to set and an additional l5 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. Phosphate: 100-150 (P2 O5) lb/acre Potash: 100-200 (K2 O) lb/acre depending on soil test. Sulfur: 30-35 (S) lb/acre pH: Add lime if below 6.0 GROUND MULCHES AND ROW COVERS The use of clear plastic mulch applied over herbicide treated soil, or black plastic ground mulch is recommended. The use of ground mulch increases soil temperature, conserves soil moisture, and controls weeds, increasing yields and is strongly recommended especially for production in western Oregon. 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 may be cost-effective where soil warming is important. (See also section on spacing). Spunbonded polyester and perforated polyethylene row covers may be used for 4 to 6 weeks immediately after transplanting depending on temperature. Research in Illinois with the varieties "Lady Bell" and "Bell Boy", over a three year period, indicates that covers should be removed after 650-675 heat units (using a base temperature of 50 F.) have been accumulated. Heat units should be based on temperatures recorded outside the covers but nearby and calculated as: the sum of (daily high+daily low)/2-50 F. 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. Research from Connecticut indicates that the use of row cover and plastic mulch is particularly cost effective when growing red, yellow or orange bell peppers for the fresh market. IRRIGATION Apply water uniformly to reduce incidence of blossom end rot. Irrigate carefully after fruit ripens to reduce fruit decay. A total of 12-15 inches may be needed in western Oregon and 25-30 inches in eastern Oregon, depending on planting date and harvest season. 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. HARVESTING, HANDLING AND STORAGE Yields of 15 to 25 tons/acre of bell peppers may be obtained for processing. Fresh market yields may range from 500 to 1000 28 lb. cartons per acre. Pimento and dried chili pepper yields range from 2 to 3 tons/acre. Pepper yields are greatly influenced by the number of harvests and season. Bell pepper types are generally hand harvested as green mature fruits. Maturity is determined when fruits are smooth and firm to the touch (a function of wall thickness). Bell peppers for fresh market must also be 3 inches in diameter and not less than 3 1/2 inches long to qualify as USDA Fancy. They can also be harvested red, which are considerably sweeter and more flavorful. Cherry types are harvested as both green and red fruits, and the banana types are generally harvested as yellow mature peppers. Jalapano and some cherry peppers have been machine harvested successfully in Michigan and California. Machine harvesting may be successful with other types especially where the peppers are intended for processing. Peppers intended for machine harvest need to be grown on raised beds in order to be harvested successfully. When red peppers are desired, a foliar spray of Ethephon (Ethrel) may be used to promote early, uniform ripening and coloring, or to ripen the par- tially ripe fruit remaining at the end of the harvest season. Check the Ethephon label for complete instructions and regulations. STORAGE (quoted from USDA Ag. Handbook #66): Sweet Peppers: Store sweet peppers at 45 to 55 F and 90 to 95 % relative humidity. Sweet, or bell, peppers are subject to chilling injury at temperatures below 45 F, and temperatures above 55 F encourage ripening and spread of bacterial soft rot. Bell peppers should not be stored longer than 2 to 3 weeks even under the most favorable conditions. At 32 to 36 F peppers usually develop pitting in a few days. Peppers held below 45 F long enough to cause serious chilling injury also develop numerous lesions of alternaria rot. Alternaria causes the calyx to mold and decay. Holding at 40 F and below predisposes peppers to Botrytis decay also. Rapid precooling of harvested sweet peppers is essential in reducing marketing losses, and this can be done by forced-air cooling, hydrocooling or vacuum cooling. Properly vented cartons are recommended to facilitate forced- air cooling. If hydrocooling is used, care should be taken to prevent the development of decay. Sweet peppers prepackaged in moisture-retentive films, such as perforat- ed polyethylene, have a storage life at 45 to 50 F up to a week longer than non- packaged peppers. The use of film crate liners can help in reducing moisture loss from the fruit. It is commercial practice to wax peppers; only a thin coating should be applied. Waxing provides some surface lubrication, which not only reduces chafing in transit but also reduces shrinkage; the result is longer storage and shelf life. Senescence of sweet peppers is hastened by ethylene. There- fore, it is not a good practice to store peppers with apples, pears, tomatoes, or other ethylene producing fruits in the same room. Low-oxygen (3 to 5 %) atmospheres retard ripening and respiration during transit and storage. High concentrations of carbon dioxide delay the loss of green color. However, high carbon dioxide also causes calyx discoloration. Chili and Other Hot Peppers: Storage temperature depends on use; see text. A humidity of 60 to 70% is recommended. Chili peppers are usually picked when ripe and are then dried and allowed to equalize in moisture content in covered piles. Water is usually added to the peppers after drying to reduce brittleness. They are then packed tightly into sacks holding 200 or more pounds and are generally stored in non-refrigerated warehouses for up to 6 months. The temperature of the warehouses depends to some extent on their construction and the way in which they are managed but chiefly on the outside temperature (50 to 75 F). Insect infestation is a major storage problem. In southern states, chili and other hot peppers are dried, packaged, and then stored at 32 to 50 F until shipped to processing plants. Storage at low temperatures aids in retarding the loss of red color and in slowing down insect activity. The moisture content of chili and other hot peppers when stored should be low enough (10 to 15 %) to prevent mold growth. A relative humidity of 60 to 70 % is desirable. With a higher moisture content the pods may be too pliable for grinding and may have to be re-dried. With lower moisture content (under 10 %) pods may be so brittle they shatter during handling; this causes losses and the release of dust, which is irritating to the skin and respirato- ry system. The use of polyethylene bags allows better storage and reduces the dust problem. The liners ensure that the pods maintain a constant moisture content during storage and up until the time of grinding; thus, they permit successful storage or shipment under a wide range of relative humidities. Packed in this manner, peppers can be stored 6 to 9 months at 32 to 40 F. Manufacturers of chili and other hot pepper products hold part of their supply of the raw material in cold storage at 32 to 50 F, but they prefer to grind the peppers as soon as possible and store them in the manufactured form in airtight containers. Freshly harvested chili or other hot peppers should be stored under the same temperature and humidity conditions as those for sweet peppers. PACKAGING Bell peppers are packaged in 25-30 lb. l l/9 bushel containers or 30 lb. cartons. Chili peppers and yellow types are packaged in 16-25 lb. lugs or 10- 20 lb. cartons. PEST CONTROL FOR PEPPERS 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 ------------------------------------------------------------------------------ trifluralin 0.5 to 1.0 lb ai/A Treflan (transplanted pepper only) Apply before transplanting and incorporate within 24 hours by cross- disking or by using a PTO rotary tiller. Transplants may be set im- mediately. Spray only once and avoid overlaps. Use lower rates on light or coarse textured soils low in organic matter. Consult label for planting crops within 12 months. (Inhibits mitosis, primarily of shoots). ------------------------------------------------------------------------ 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). ______________________________________________________________________________ TRANSPLANTS ONLY Weed Treatment Active Ingredient Per Acre and Application Comments ------------------------------------------------------------------------------ DCPA 9 lb ai/A Dacthal 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 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. ______________________________________________________________________________ POSTEMERGENCE Weed Treatment Active Ingredient Per Acre and Application Comments ------------------------------------------------------------------------------ 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 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 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 FOR CURRENTLY LEGAL REGISTRATIONS, RATES AND COMPLETE INSTRUCTIONS. Insect and Description Control, Active Ingredient Per Acre --------------------------------------------------------------------------- Armyworms, Cutworms, Loopers. permethrin - 0.1 to 0.2 lb Loopers only. Lannate - 0.45 lb Small to large larvae that feed on stems, leaves, and fruit. carbaryl - 2.0 lb Cutworms and fall armyworm only. Asana - 0.03 to 0.05 lb Bacillus thuringiensis - 1 to 2 qt. Use a spreader-sticker to enhance control. Orthene - 0.5 to 1 lb Bell peppers only. --------------------------------------------------------------------------- Green peach aphid endosulfan - 0.5 to 1 lb Myzus persicae Phosdrin - 0.25 lb Yellowish, pink to pale green plant louse. malathion - 1.25 to 1.5 lb Where aphids have become phosphamidon - 0.5 lb resistant to most organic phos- phate insecticides, endosulfan Dibrom - 1 lb is the preferred material. dimethoate - 0.25 to 0.33 lb Lannate - 0.45 lb Metasystox-R - 0.5 lb Orthene - 0.5 to 1 lb bell peppers only diazinon - 0.25 lb Vydate L - 0.5 to 1.0 lb --------------------------------------------------------------------------- Garden symphylan Dyfonate - 2 to 4 lb. Preplant Scutigerella immaculata soil treatment. Do not rotate with carrots. Small, white, centipede-like animals active in soil. parathion - 6 lb - replant soil treatment. Telone II or C-17 preplant --------------------------------------------------------------------------- Flea beetles including azinphosmethyl - 0.5 lb Western potato flea beetle Epitrix subcrinita carbaryl - 1 lb Small, oval, shiny bronze jump- Asana - 0.03 to 0.05 lb ing beetles. Chew small circu- lar holes in foliage. methoxychlor - 1.75 to 2.25 lb rotenone - 0.35 to 0.5 lb endosulfan - 0.5 to 1 lb permethrin - 0.1 to 0.2 lb Bell peppers only. --------------------------------------------------------------------------- Spider mites dicofol - 0.375 to 0.75 lb. Do Tetranychus spp. not feed. Tiny, spiderlike animals found Phosdrin - 0.5 lb on undersurfaces of foliage. --------------------------------------------------------------------------- Wireworms diazinon - 3 to 4 lb Limonius spp. Dyfonate - 4 lb Brown, jointed larvae of click Do not rotate with carrots. beetles. Kill young plants, in- jure older ones. 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. PEPPER -- MOSAIC VIRUSES Cause: Several viruses transmitted by aphids, including alfalfa mosaic virus, potato virus y, pepper mottle virus, tobacco etch virus, and cucumber mosaic virus. Tomato spotted wilt virus also infects pepper but is transmitted by thrips.Symptoms: Bright yellow mottle, ringspots, and line patterns on both leaves and fruit. Fruit and plants are stunted, and sometimes exhibit lateral leaf rolling. Many of these viruses overwinter in perennial legumes such as alfalfa and various clovers. Several common weeds are hosts of some of the viruses. ~Control: Plant as far as possible from alfalfa fields, clover fields, and permanent pastures containing clovers. Keep area around fields as weed-free as possible. Aphid control is helpful but will not provide perfect control. If tomato spotted wilt is a problem, control of thrips will be of some help. --------------------------------------------------------------------------- PEPPER -- ANTHRACNOSE Cause: Gloeosporium, a fungus found on both peppers and eggplants. This fungus (like many other anthracnose fungi) is saprophytic during part of its life cycle and may survive from year to year in the soil crop refuse. Symptoms: Round sunken spots appear on both green and ripe fruits. Spores develop on the infections often in radiating circles around the center, which later may contain masses of pink spores. The seed may be infected and often seedlings have the disease, which later moves into the developing foliage. Such infections are often unnoticed until the fruits start to grow, at which time the fruit rot phase may become serious. ~Control: 1. Destroy all plant refuse by burning or deep plowing. 2. Rotate crops. 3. Spray fixed copper fungicide. See product label. 4. Spray Maneb at 1.2 to 1.6 lb ai/A. Do not apply more than 9.6 lb ai/A/season. Do not apply within 7 days of harvest. --------------------------------------------------------------------------- PEPPER -- BACTERIAL SPOT Cause: A bacterium Xanthomonas vesicatoria, that is seedborne and frequently comes with transplants. It will live over winter in infected debris and is spread by irrigation. Pickers and equipment also spread the disease, particu- larly when the plants are wet. Symptoms: Water-soaked spots on leaves that turn gray with black centers. They frequently are surrounded by a yellow halo. They later fall out, leaving holes apaproximately 0.25 inch in diameter that give the plant a ragged look. Fruit spots are at first water-soaked and later become raised and scabby. ~Control: 1. Plant disease-free seed or transplants. 2. Limit overhead irrigation or, better, produce peppers under furrow or drip irrigation. 3. Do not pick or cultivate plants when they are wet. Chemical control: If disease is present, spray with fixed copper during wet period. Several materials are labeled. See product label for rates. Residue: Copper -- exempt. --------------------------------------------------------------------------- PEPPER -- CERCOSPORA LEAF SPOT Cause: Cercospora melongenae (mostly on eggplant), Cercospora capsici (mostly on pepper), fungi. These organisms survive the winter on dead plant parts. Symptoms: Leaf spot infections on eggplant are small, chlorotic, gray turning to brown, with tiny, dark specks containing spores arranged in circular fashion. Eggplant fruits are not attacked. Leaf spot on pepper is at first water-soaked and up to inch in diameter, later becoming tan in shade with a dark marginal ring. Centers may often drop out as they age. Spots develop on stems and petioles. When numerous, the leaves turn yellow and may drop or wilt. Defoliation is often serious, exposing peppers to sunscald. ~Control: 1. Destroy by burning or deep burying old pepper and eggplant refuse. 2. Use seed from disease-free areas. 3. Rotate crops. 4. Spray Maneb at 1.2 to 1.6 lb ai/A. Do not apply more than 9.6 lb ai/A/season. Do not apply within 7 days of harvest. 5. Spray fixed copper fungicide. See product label. -------------------------------------------------------------------------- PEPPER -- COMMON (Tobacco) MOSAIC Cause: A virus spread by aphids and mechanical means. It overwinters on wild perennial hosts. Symptoms: Varying types of yellow and green leaf mottling accompanied by curling and leaf distortion are displayed. In the early season, plants are frequently stunted and very few fruits develop. Plants infected later in the season (during or after blossom) show slight mottling only. Infected fruits are often yellowed, shriveled, mottled, irregularly shaped, and dwarfed in size. ~Control: 1. Maintain rigid weed control in nearby plantings. 2. Controlling aphid vectors with insecticides may help reduce spread. 3. Do not smoke around the plants, particularly in the greenhouse. 4. Wash hands after handling infected plants. 5. Rouge infected plants early. 6. Resistant cultivars include `Yolo-wonder', `Pennbell', `Bell Boy', `California Wonder 300', `Orobelle', `Bell Tower', `Elisa', `Marquis', `Belle Star', `Big Belle', `Four Corners', `Sweet Belle', `Bolero', `Lamuyo', `Emerald Giant', `Prima Belle', `Lady Bell', `La Bamba', `Jupiter' and `Keystone Resistant Giant'. Hot types that are resistant include `Anaheim TMR 23', `Caloro', `Santa Fe Grande', `Tam Jalapano', `Tam Serrino Hidalgo', and `Gold Spike'. --------------------------------------------------------------------------- PEPPER -- LATE BLIGHT See Potato and Tomato - Late Blight --------------------------------------------------------------------------- PEPPER -- ROOT ROT Cause: Phytophthora capsici, a fungus. This soil-inhabiting organism causes root rot in pepper and eggplants and is most active in moist, warm weather. Symptoms: At soil level, dark-greenish, water-soaked spots occur which often girdle the stem, causing the plants to wilt and die. Foliage leaf spots develop, which are often water-soaked and irregular in shape, later becoming a light-brown shade. The fruit shows similar spots often enlarging to cover the entire fruit, which later dries and becomes mummied. ~Control: 1. Plant only in clean soil where the disease has not occurred. 2. Use disease-free seed. 3. Practice light irrigation and crop rotation. 4. Ridomil 2E can be used to control this problem. A full program consists of a preplant application followed by two postplant applications. See product label. --------------------------------------------------------------------------- PEPPER -- VERTICILLIUM WILT Cause: Verticillium dahliae, a fungus organism. The Verticillium wilt organism is a widespread soil inhabitant which affects a wide range of herbaceous and woody plants. Symptoms: Infected plants show a stunting of growth accompanied by yellowing and inward rolling of the leaves. The disease development on eggplant begins with a yellowing of the lower leaves, reduced size and vascular discoloration. It is seedborne in the eggplant. The fungus gains entry through the root system, and progress in the plant is primarily through the vascular system. ~Control: 1. Old crop remains should not be left on the field or added to the compost pile, as this encourages future infections. 2. Crop rotation with nonsusceptible grasses and grains may be of some small value, but nothing can really be done to eradicate this disease. 3. Avoid tomatoes and potatoes in any rotation, as these are favorite hosts. 4. There are as yet no resistant varieties. ______________________________________________________________________________ ______________________________________________________________________________ --------------------------------------------------- --------------------------------------------------- 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 of questions to your County Extension Agent or Dr. N. S. Mansour, Department of Horticulture, Oregon State University, Corvallis, OR 97331. ---------------------------------------------------