A3687

K.A. DelahautA.C. Newenhouse

Growingtomatoes,peppers, andeggplants in WisconsinA guide for fresh-market growers

ContentsPlant description, 1

Site selection, 2

Cultivar selection, 2

Planting, transplanting, and culture, 5

Soils and nutrient management, 8

Irrigation, 10

Harvest, handling, and storage, 10

Insect management, 12

Disease management, 17

Environmental disorders, 20

Weed management, 21

Additional reading, 21

Successful fresh-market gardening involves

more than just a talent for growing high-quality

vegetables. You also need to find a market for

them. Before you start, visit other growers,

develop a marketing plan, and evaluate the

feasibility of your proposed business. Think

about what is unique about your product. Are

you promoting the product for taste, freshness,

health benefits, value-added, or time of avail-

ability? For assistance determining your mar-

ket, consult with your county Extension agent or

refer to Extension publication Direct Marketingof Farm Produce and Home Goods (A3602).

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1

Tomatoes have becomethe second-most popu-lar vegetable, behind

potatoes, in the United States.And salsa, which uses toma-toes and peppers liberally, has

become the most popular condi-ment in the United States, surpass-

ing even ketchup. Consumersexpect fresh, flavorful, vine-

ripened tomatoes to be avail-able each summer to supplant

the hard, bland tomatoes com-monly available from the supermar-

ket. Tomatoes and peppers containsignificant amounts of the vitamins A

and C. With the many varieties ofsweet and hot peppers available,

market gardeners can easily find a niche market fortheir product. Value-added products such as driedpepper wreaths command a high price. Specialtyeggplant varieties such as the elongated Asian egg-plants or varieties with white-skinned fruit are oftenmore marketable than the traditional oval eggplant.

Plant descriptionTomatoes, peppers and eggplants belong to theplant family Solanaceae, the nightshade family.

TomatoesThe tomato, Lycopersicon esculentum, is native tothe Andes mountain region of South America.Tomatoes were introduced to Europe in the 1500s,although until the 1700s they were believed to bepoisonous if eaten. The foliage and some other greentissues of tomato plants do contain a toxic chemical,tomatine. Although tomatine is present in unripetomato fruit, the levels are low enough to be nontoxic.

Tomatoes are tender, warm-season, herbaceousperennials grown as annuals in Wisconsin and othercold climates. Plants may be determinate, semi-determinate, or indeterminate in habit. Determinatevarieties are compact plants which are often smallerthan the indeterminate varieties. Each shoot on adeterminate plant ends in a flower cluster, and con-

sequently a fruit cluster. Determinate tomato plantstend to produce fruit all at once. Indeterminate culti-vars are vining or sprawling in habit. The shoot tipscontinue to grow and flower clusters are borne in theleaf axils of the expanding shoot. Indeterminatetomato plants yield fruit over a long time. Determinatetomatoes, which grow on the ends of branches, tendto ripen earlier than indeterminate tomatoes becausethe fruit receives more heat and sun.

Leaves of the tomato plant are covered with fine hairsthat emit the characteristic tomato smell whencrushed. Plants have a deep taproot system withmany secondary side roots. In loose soils, vigorousroot systems may extend down 10 feet.

Tomato flowers are largely self-fertilized and are pri-marily wind pollinated. Individual flowers are borne inclusters of 4–8 flowers, and a single plant may pro-duce 20 or more flower clusters. Depending upon thevariety, the resulting fruit may be red, yellow, orange,pink or purple, and may be oblong, round, or pearshaped.

PeppersThe peppers grown commercially belong to twospecies: Capsicum annuum which includes all sweetpeppers and hot chili peppers, and Capsicumfrutescens, the tabasco pepper. Many people con-fuse the black and white pepper used as a season-ing with the pepper fruit grown for fresh market;those peppers belong to the species Piper nigrum.

plant d

escription

Figure 1. Determinate plants (left) form flowers

at the ends of branches while indeterminate

plants (right) produce flowers in leaf axils.

2Peppers originated in Mexico and Central America. Itis believed that peppers were domesticated in Mexicoas early as 7500 B.C. Most cultivars contain varyingamounts of capsaicin, the chemical responsible forthe heat, or pungency, of peppers. Capsaicin is moreconcentrated in the seeds and internal walls (placenta)where the seeds are attached. Removing these tis-sues can reduce the pungency of hot peppers.

Peppers are tender herbaceous perennials and aremore susceptible to cold weather injury than toma-toes. In Wisconsin and other northern regions, pep-pers are grown as warm season annuals. The rootsystem is shallow and fibrous.

Pepper flowers are self-pollinated by insects,although about 12% will cross with other plants. Amild variety can become hot because of cross polli-nation with a pungent cultivar. Pepper fruit may beborne on the plant pointing either up or down.

Pepper fruit may be green, yellow, red, purple, orbrown. As peppers ripen, the carotenoid capsanthinis produced and green peppers develop into othercolors. This process depends on the fruit being in theproper stage of ripening and temperatures beingbetween 65° and 75°F. Temperatures below 56°F willinhibit coloring of the fruit. Capsanthin is absent inpeppers that are picked when unripe and still green.

EggplantsThe eggplant, Solanum melogena, is native to Indiaand China. As with tomatoes and peppers, the egg-plant is a tender perennial grown as a warm-seasonannual in Wisconsin. The plant is an indeterminate,erect bush that reaches 2–4 feet tall when fully grown.

Eggplants have an extensive, fibrous root system.Flowers are borne singly or in clusters in leaf axils.Flowers are self-fertile but cross pollination doesoccur. Eggplant is pollinated by insects. The fruit maybe oval, oblong, or round. Fruit color may be purple,purple-black, brown, green, pink, white, red, or yellow.

Site selectionTomatoes, peppers, and eggplants require full sun.Choose light, warm, well-drained, fertile soil. Soil pHshould be between 5.5 and 7.5. Tomatoes are notgrown on muck soils because high soil organic mat-ter results in too much foliage at the expense of fruitproduction.

Cultivar selectionChoose cultivars according to your own situation andneeds. Table 1 lists some recommended tomato,pepper, and eggplant cultivars. When deciding whatto grow, consider market demands, the length of yourgrowing season, your soil, pests, diseases, irrigation,cultivars other growers like, and cultivars you person-ally like. If trying a new cultivar, do not use it exclu-sively. Grow new trials next to old standbys so you

may compare the characteristics objectively.

TomatoesTomato cultivars for Wisconsin are catego-

rized by use: early crop, main crop, paste,and small fruited (cherry).

If a field has a history of problems with Verticilliumwilt and Fusarium wilt, consider planting a culti-

var that is resistant to these diseases. Resistantvarieties are indicated by the letter following thecultivar name. “V” indicates resistance toVerticillium wilt, “F” indicates resistance toFusarium, and “N” indicates resistance tonematodes.

3site selection

Rcultivars

Table 1. Recommended cultivars for Wisconsin

F1 hybrids

Many cultivars havethe designation“F1 hybrid.” An F1hybrid is createdwhen two purebredstrains of plantsare crossed, pro-ducing identicaloffspring. F1 standsfor “filial 1,” thefirst generation ofhybrids after thecross was made.Seeds of F1 hybridswill not producetrue to form—thecross between theoriginal parentsmust be made eachtime.

Tomatoes

Early cropindeterminateEarly Girl (V)

determinateNew Yorker (V)Wayahead

Main cropindeterminateBeefmaster (VFN)Better Boy (VFN)Burpee’s Big BoyJet Star (VF)Pink Girl (VF)

indeterminate, heirloomBrandywineYellow Brandywine

determinateCampbell 1327 (VF)Celebrity (VFN)Floramerica (VN)Heinz 1350Siletz (V)Ultra Sweet (VF)

CherryindeterminateGardener’s DelightSweet 100Yellow Pear

determinatePatio (V)PixieSmall-Fry (VF)Tiny Tim

PastedeterminateRoma VFViva Italia

Peppers

HotFlashHabañeroHot PortugalHungarian Yellow WaxOrtegaSpanish SpiceSuper CayenneSuper Chili

Sweet (early)AceCanapeEarly CrispEarly Niagara GiantGypsy (yellow)LipstickYellow Belle

Sweet (midseason)Bell BoyGolden BellHybelleIslander (purple)IvoryLady BellMa BelleNorth StarPortos YellowPurple BeautySweet Cherry (pickling)Ultra SetWhite LamuyoYolo Wonder B

OtherBiscayne (cubanelle)Giant Yellow BananaIvory BananaSugar BananaSuper Shepherd(ramshorn)

Eggplants

AsianAgoraIchibanOrient Express

Oval (standard)Black BeautyBlack MagicDuskyEarly BeautyGhostbuster (white)Machiaw (pink)Neon (pink)Rosita (pink)Tango (white)

MiniatureBambino

Older open-pollinated cultivars known as heirloomvarieties have become increasingly popular.Heirloom varieties often offer better flavor and some-times unusual characteristics. Growers can savegenetically identical “true” seed from open-pollinatedplants, whereas seed from hybrid plants is not true tothe genetic make-up of the parent plant. Many heir-loom varieties have no disease resistance and areoften more susceptible to physiological disorderssuch as catfacing.

PeppersThere are many different types of peppers grown inthe United States (table 2). Peppers can be classi-fied based on their relative hotness. The ScovilleHeat Unit is a measure of pepper pungency. Purecapsaicin is approximately 16,000,000 Scoville units.

Habañero type peppers are the hottest with 300,000Scoville units. The units will vary for each type ofpepper based on variety, maturity, and whether thepepper is fresh or dried. Typically, pungent peppersrequire hot, dry conditions to fully develop their flavorand may not produce a suitable harvest in cool, wetsummers.

EggplantEggplant breeding programs have focused on theproduction of compact plants, cool temperature tol-erance, and the production of varieties that ripen in ashorter growing season. Resistance to cucumbermosaic and tobacco mosaic viruses have been bredinto many cultivars currently available.

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Type Size Shape Color at maturity Scoville Heat Units Uses

Ancho 2–3" W x 3–6" L heart-shaped red or brown 1,000–1,500 chili rellenos, moles,dried as poblanosfor decoration

Bell 3–4" W x 4" L blocky bell red, yellow, 100–600 fresh in salads or orange, brown baked

Cayenne 1" W x 10" L thin and tapered, red 30,000–50,000 dried powderslightly curved

Habañero 1–2" W x 1–2" L irregularly spherical orange 150,000–300,000 fresh in salsas

Jalapeño 1" W x 3" L blunt and tapered red 2,500–5,000 fresh in salsas

Pimento 2–3" W x 2–4" L flattened bright red 0 fresh in salads,pickled, dried aspaprika

Pequín 1⁄4–1⁄2" W x 1⁄4–1⁄2" L round to conical dark red 50,000–100,000 dried and used in soups and sauces

Serrano 1⁄2" W x 1–4" L tapered green or red 10,000–20,000 fresh or canned

Thai 1⁄2–3⁄4" W x 11⁄2" L tiny, bullet-shaped dark red 30,000–100,000 fresh in stir frydishes or dried asa powder

Wax 1" W x 2–8" L thin and tapered yellow 0–40,000 pickled or mildvarieties can be used fresh in salads

Table 2. Descriptions of various pepper types

5Planting, transplanting,and culture

Starting seedsTomatoes, peppers, and eggplants all require a long,warm growing season and therefore are typicallystarted in the greenhouse in Wisconsin and trans-planted outside after all danger of frost has passed.Tomatoes are started 4–6 weeks before they aretransplanted to the field. Peppers should be started6–8 weeks prior to field transplanting and eggplantsshould be started 10–12 weeks before the frost freedate for the area. The best transplants are between4 and 6 inches tall without flower buds.

You can buy or mix your own sterile potting mix forstarting transplants. The mix should include peat,sphagnum, or compost to retain moisture; vermiculiteor perlite for aeration; and mineral and nutrientsources to encourage growth after the first rootsform. Fill plastic or polystyrene cell trays with media,or make individual blocks with a soil blocker. Cellsthat are 2 inches in diameter work well. Prevent bac-terial and fungal infections by sterilizing transplanttrays in a 10% bleach solution before you plant. Plantseeds 1⁄4-inch deep. Label transplant trays with culti-var and planting date. Keep media moist but not wet.Germination will occur within 10 days. Maintain soiltemperature at 80°–90°F with a heating mat or cable.After germination, soil temperature can be main-tained at 70°F. Keep daytime temperatures in thegreenhouse at 70°–75°F and 60°–62°F at night.

planting

, transplanting

, and culture

Last spring killing frost First fall killing frost

September 13–19

September 20–26

September 27–October 3

October 4–10

October 11–17

October 18–24

Figure 2. Approximate dates for first and last killing frosts.

May 31–June 6

May 24–30

May 17– 23

May 10–16

May 3–9

April 26–May 2

Thin seedlings to one plant per cell or plug, or oneplant every 21⁄2 inches if grown in undivided flats. Tendays before transplanting to the field move plants intoa cold frame where lower temperatures will hardenthem off. These plants cannot tolerate any frost orcool temperatures, so be sure to bring them insidethe greenhouse if the temperature threatens to dipbelow 40°–45°F. Pepper fruit set later may be limitedby cool temperatures at this stage.

Reduce watering and withhold fertilizer while plantsare in the cold frame to help harden off transplantsand acclimate them to field conditions. If left in thecold frame too long, plants become over-hardenedand require more time to resume growth when trans-planted to the field.

Soil preparationControl weeds prior to planting the bed. Work beds7–8 inches deep to promote deep rooting. Raisedbeds are an alternative to the conventional field plant-ing method. They improve soil drainage and allowaccess to the crop without causing soil compaction.Raised beds are typically 4–5 feet wide and 100 feetlong. The width is determined by the type of equip-ment used and by the crop. Leave a 1-foot aisle oneither side of each bed to accommodate foot traffic.

TransplantingTransplants are set out after all danger of frost haspassed (see figure 2). Tomato transplants may be setout after May 20 in southern locations while peppersand eggplants should be held back until June 1.Growers along Lake Michigan should delay plantingan additional week while northern growers shouldwait 2 weeks before transplanting. Tall tomato plantswill form roots along their stem and can be planted inshallow trenches with their roots and some of thelower portion of the stem covered with soil. Don’tplant the transplants too deep since soil temperaturedrops the further down you go. Do not bury pepperand eggplant stems deeper than the transplant soilline. Transplants can be planted with a tractor-pulledmechanical transplanter or by hand.

Tomato cultureTomatoes grow best when daytime temperaturesaverage 75°F and nighttime temperatures average68°F. A 10°F difference between day and night tem-peratures gives optimum fruit production.Temperatures below 60°F or above 80°F impairgrowth and fruit set, although a few determinate vari-eties can set fruit at temperatures as low as 40°–50°F.

Plant tomatoes 18–24 inches apart in rows 3–4 feetapart. Determine your staking, trellis, or caging sys-tem before you plant.

Supports for tomatoes. Tomatoes can be staked orallowed to sprawl depending on the variety and theinclination of the grower. Staking requires time, effort,and trellis materials but you can fit more plants in asmaller area and the fruit is larger, cleaner, earlier,and easier to harvest than if plants are left to sprawl.Indeterminate varieties are usually trellised in a bas-ketweave system in smaller fresh-market operations.Determinate varieties can be left unstaked, tied toone stake, or trellised.

Choose stakes 1 inch square and 4–7 feet longdepending on tomato cultivar height. Drive stakes 12inches into the ground between every other plant forthe length of the row. Leave a path to carry fruit out ofthe field. Strengthen the framework with an additionalstake on each end driven at an angle and tied to theend stake.

Remove lower tomato plant suckers or sideshootswhen they are 2–4 inches long, up to the one belowthe first flower cluster. Do not smoke cigarettes orhandle chewing tobacco while you work with tomatoplants since viral diseases may be carried on yourhands from the tobacco.

When the plants are about 12 inches tall, before theyfall over, begin the basketweave at 8–10 inchesabove the ground. Using strong, durable “tomatotwine” which comes in a box that attaches to yourbelt, tie the twine to an end stake and pass the twinealong one side of the plants and around each stake,pulling it tight as you go. At the end of the row, go tothe other side of the plants and loop twine aroundeach stake until you are back where you started. Tiethe twine to the first stake. To make the string easierto handle, you can thread it through a 12–36 inchstick with a hole at the end.

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7As the plants grow, add strings 6–8 inches above theprevious string until you have a trellis of 4 strings. Ifyou stake your plants, be sure to set the stakes atthe time of transplanting to avoid damaging the rootsystem during the staking process.

Caged plants do not require pruning and will pro-duce more fruit than the same variety which hasbeen staked. Caged plants ripen later because ofthe lack of pruning but the incidence of sun scald isalso reduced by the shading effect of the foliage.

Greenhouse tomatoes. Tomatoes are becoming morepopular as a greenhouse crop to extend the shortWisconsin growing season. Typically, early springand fall crops are produced in a plastic hoop house,avoiding the dark months of December, January, andFebruary. Read about the details of greenhousetomato production in Commercial GreenhouseProduction: Tomatoes, from Kansas State Extension.This publication covers costs, returns, construction,heating, ventilation, tomato varieties, growth, training,watering, fertilizer, pests, and diseases. As with gar-den culture, temperatures between 70°–80°F andnight temperatures of 65°F favor the best develop-ment. When the fruits are ripe, they are harvested byhand. The tomatoes should be at the firm, red stagebefore harvesting. Wisconsin greenhouse growerscan expect tomato yields of 3 lb per square foot forthe fall crop and 5–6 lb per square foot in spring.

Pepper culturePeppers grow best at temperatures of 70°–80°F dur-ing the day and 65°–70°F at night. Pepper fruit setonly occurs at temperatures of 75°–86°F. Night tem-peratures below 72°F will result in poor fruit set.Temperatures greater than 90°F or less than 55°Fresult in heavy blossom drop.

Peppers can be planted in twin rows 14 inches apartand 40 inches from the center of one double row tothe center of the next double row. Plants are 12–18inches apart in the row. This planting configurationincreases shading and decreases sun scald.Peppers do not require support.

Eggplant cultureOptimum temperatures for eggplant growth arebetween 75°–85°F during the day and 65–75°F atnight. Allow 30–36 inches between rows and 18–24inches between plants. If the field has a history ofproblems with potato beetles or flea beetles, con-sider protecting the plants with row covers at trans-planting. Eggplants do not require support.

Season extendersYou can lengthen the growing season by protectingplants from late spring frosts and early fall frosts.There are a variety of ways to prolong the growingseason, including planting on a southern slope, cre-ating a warmer microclimate using floating row cov-

planting

, transplanting

, and culture

Plants Spacing (inches)b DaysPlanting time in southern WIa needed for Between Between to first Estimated yield

Vegetable Indoors Outdoors 100 ft of row rows plants harvestc (lb/ft of row)d

Tomato April 15 May 20 (plants) 34–60 36–42 18–36 65–80 2.00–4.00

Pepper April 1 June 1 (plants) 50–60 30–36 18–24 60–70 2.00

Eggplant March 15 June 1 (plants) 50–60 30–36 18–24 70–80 1.75aPlant about 1 week later along the lower lake shore and in the central part of state and about 2 weeks later in northerncounties.

bIf using a plate-type seeder, spacing between plants will be determined by plate configuration.cCultivars vary greatly in time needed to reach harvest stage; extend the harvest season by planting cultivars of differentmaturity dates or by making successive plantings of the same cultivar.

dEstimated yields under less than ideal growing conditions; actual yields will vary widely with weather, soil fertility andcultural practices.

Table 3. Planting guide

ers, dark plastic mulch to warm the soil, clear plastictunnels, cold frames, or using windbreaks to shieldplants.

Floating row covers. Floating row covers of spun-bonded polypropylene allow sunlight and water topass through the fabric, but prevent insects fromreaching the plants. Row covers can be used to coverlow-growing crops and protect them from frost. Theyalso serve as windbreaks and protect crops againstinsect pests. Depending on the fabric weight, rowcovers can provide 4°–8°F of frost protection.

Row covers are not typically used for warm-seasoncrops such as tomatoes, peppers, and eggplants,but they may serve as a temporary emergency frostprotection blanket. Row covers on eggplants will pre-vent flea beetles and Colorado potato beetles fromdefoliating plants.

Row covers may be draped over the crop or sup-ported by wire hoops. If you gather the edges in aloose accordion-type fold and loosely bury them insoil along the crop row, then as the crop grows it willpush up enough fabric to maintain a “floating” cover.With tender crops, or late fall crops which will grow tomarket maturity under row covers, consider support-ing the row cover fabric to prevent abrasion damageto plants. Use 9-gauge wire hoops 6 feet apartburied 1 foot deep on each side on the row.

Row covers can be held in place by burying theedges or by weights such as reebar. Completely sealall four edges to the ground if you use row covers asan insect barrier. If not using row covers as an insectbarrier, remove covers when the average daily tem-perature is warm enough for crop growth. Be sure tovent the beds on hot days and to let plants hardenoff for a few days to prevent burning before com-pletely removing the row covers. Harden plants byremoving covers on overcast days or for a few hourson sunny days.

Plastic mulch. Plastic mulch raises the soil tempera-ture early in the season and can boost crop maturityby 1–3 weeks. Plastic mulch also suppresses weedsand reduces some disease problems by providing abarrier between soilborne pathogens and leaves.Lay wide strips of 1.25–1.5 mil black polyethyleneplastic over the beds before planting, using a plasticmulch layer or by hand. Place soil along all theedges of the plastic to anchor it from wind. Clear

plastic raises the soil temperature more than darkplastic, but it doesn’t shade out weeds. If puddlesform on top of the plastic, poke tiny drain holes toprevent a wet environment suitable for fungi.

Cut or burn holes (with a propane torch) into theplastic where you want to plant. Remove loose plas-tic flaps which might abrade tender stems. Plantsgrown on dark plastic need more water. Before layingplastic, consider placing drip irrigation tape alongplant rows under the plastic.

Tunnels and cold frames. Slitted clear poly tunnelsincrease daytime temperatures 10°–30°F, and pro-vide 1°–4°F of frost protection. Cold frames can beused to harden off crops before transplanting into thefield. Consult the references listed at the end of thispublication for more information on cold frames andtunnels.

Windbreaks. A grove of trees to block the prevailingwinds can serve as a windbreak. Windbreak effectstypically extend to 21⁄2 times the height of the wind-break. For example, a 10-foot-tall windbreak willreduce air flow up to 25 feet away on the lee side.Less-permanent windbreaks include planting a tallcover crop such as grain rye upwind or between rowsto reduce wind gusts or placing a semipermeablefabric or poly fence on the upwind edge of the field.

Soils and nutrientmanagementObtain a soil test to determine the level of availablenutrients before planting a field for the first time androutinely thereafter at least once every 3 years. After3 years, soil conditions can change enough to makeyour current fertility management program obsolete.For information on how to collect good samples andwhere to send them for analysis, see Extension publi-cation Sampling Soils for Testing (A2100).

Routine soil tests include pH, organic matter content,phosphorus, and potassium. Special tests are avail-able on request for nitrate-nitrogen, calcium, magne-sium, sulfur, boron, manganese, and zinc. You willreceive the results of your soil test along with fertilizerrecommendations based on your cropping historyand planned use of the field.

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9Soil pH should be between 6.8 and 7.0 to maintainthe availability of micronutrients. If the soil pH isbelow 6.0, apply aglime to raise the pH to the6.8–7.0 range.

Fertilizer needsPlants take up nitrogen as nitrate (NO3

–) or ammo-nium (NH4

+), phosphorus as phosphate (P2O5), andpotassium as potash (K2O). These chemicals, as fer-tilizers, can come from organic or inorganic sources.With adequate environmental conditions, soilmicrobes break down organic matter and supply thechemicals that plants need to their roots. Organicfertilizers can also improve soil tilth and health.Inorganic fertilizers can be used to supply a morereadily available form of primary nutrients to plants.

Organic fertilizers can come from a variety ofsources such as manures, compost, fish meal, andbone meal. Each material contains varying amountsof specific nutrients. Table 4 lists organic fertilizersand the amounts of nutrients in each. For more infor-mation on this subject, refer to Extension publicationOrganic Soil Conditioners (A2305). Table 5 lists

guidelines for nutrient management to compare withyour soil test results.

soils and nutrients

Table 4. Nutrient composition of various organicfertilizers

Material N P2O5 K2O

Alfalfa hay 2.0–3.0 0.2–0.6 2.0–3.2

Bone meal 0.2–1.0 12.0–14.0 —

Composta 0.5–3.5 0.5–1.0 1.0–2.0

Fish meal 9.0–11.0 5.0–8.0 0.0–3.0

Greensand — — 7.0

Manure, cow 0.5–0.7 0.2–0.4 0.5–0.8

Manure, sheep 1.0–2.0 0.7–1.0 0.5–2.0

Manure, poultry 1.1–1.7 1.0–1.3 0.5–1.0

Rock phosphate — 20.0–30.0 —

Soybean meal 7.0 0.5 2.3

aNutrient analysis of compost will vary based on thesource.

Table 5. Annual nitrogen, phosphate (P2O5), and potash (K2O) recommendations

Nitrogen Phosphate and potash

Organic Amount to applya

matter Amount to apply Yield goal P2O5 K2O

Vegetable % lb/a oz/100 sq ft tons/a lb/a oz/100 sq ft lb/a oz/100 sq ft

Tomato <2 140 5.25 20–25 40 1.5 180 6.75

2.0–4.9 120 4.5

5–10 100 3.75

>10 80 3.0

Pepper <2 100 3.75 8–10 10 0.4 50 1.9

2.0–4.9 80 3.0

5–10 60 2.2

>10 40 1.5

Eggplant <2 140 5.25 10–12 40 1.5 180 6.75

2.0–4.9 120 4.5

5–10 100 3.75

>10 80 3.0aAmounts of P2O5 and K2O are for optimum soil test levels. Apply half the given rate if the soil test is high and omit if the soil test is exces-sively high. If soil test is low or very low, increase rates according to the soil test recommendations.

10Fertilizing tomatoes. Apply phosphorus and potas-sium according to the soil test recommendationsbefore planting, and work them into the soil. On fine-textured soils incorporate nitrogen fertilizer beforeplanting. On coarse-textured soils, apply 20–40 lbnitrogen/acre (0.75–1.5 oz/100 square feet) beforetransplanting tomatoes and sidedress the remainderin one or more applications after the fruits set.

Fertilizing peppers. Peppers require high soil fertilityearly in the growing cycle. Apply phosphorus andpotassium according to the soil test recommenda-tions before planting. Use a starter solution high innitrogen and phosphorus when setting out trans-plants and sidedress one or two applications of nitro-gen later in the season. If foliage starts to turn fromdark green to pale green or yellow, peppers may below in nitrogen.

Fertilizing eggplants. Eggplants also use largeamounts of nutrients. Apply phosphorus and potas-sium according to the soil test recommendationsbefore planting. A high phosphorus fertilizer shouldbe used at transplanting to prevent shock. Applyone-fourth of the total nitrogen as a sidedress attransplanting and again every 3 weeks for optimumgrowth.

IrrigationMoisture stress can reduce crop yields. If leaves beginto wilt mid-day, plants are moisture stressed. Plantsthat wilt intermittently may produce smaller yields,while plants that wilt frequently or that wilt too longoften die due to irreversible cell damage. Both dripand overhead sprinkler irrigation systems are effec-tive, such as trickle tape, solid set, and traveler hosewheel. Drip irrigation works particularly well with col-ored plastic mulch that is used as a season extender.

Tomatoes, peppers, and eggplants require 1 inch ofwater every week. Irrigate every 5–10 days depend-ing on the soil type and the frequency of rain. Soakthe soil to promote deep rooting, but keep the foliagedry to prevent the development and spread of foliardiseases. If using overhead sprinklers, water early inthe day so foliage can dry out quickly. Some com-mercial growers use the presence/absence of blos-som end rot in tomatoes and peppers as an indicatorof whether their irrigation schedule is adequate.

Blossom end rot is a physiological disorder thatoccurs when calcium uptake is inhibited by low soilmoisture.

Irrigation scheduling software is available from theUniversity of Wisconsin-Extension to help you deter-mine your irrigation needs. For more information onthis software, contact your county Extension agent.

Harvest, handling, andstorage

TomatoesTomatoes grown for local markets are harvested byhand when they are sweet and have reached thetable ripe stage. Consumers list the vine-ripened fla-vor of fresh tomatoes as their strongest market attrac-tion. Mature green tomatoes will ripen off the vine, butwill not acquire their full flavor.

The USDA has developed a classification of tomatomaturity (table 6). This information can be helpful forplanning when you’ll need additional harvest labor.Ten days elapse from the mature green state to tableripe tomatoes.

Handle tomatoes gently since they bruise easily.Tomatoes may be hydrocooled in a water bath toremove field heat, but do not chill the fruit, sincetomatoes will not ripen further once chilled. Tomatoesmay also be simply wiped clean. Do not stack themhigher than two layers while harvesting and packing.Pack tomatoes in shallow cardboard boxes or trays.

Tomatoes are sensitive to cold temperature. If thetemperature is above 55°F, tomatoes will continue toripen and improve their flavor. Do not store tomatoesbelow 55°F. Also, never allow ice to touch tomatoessince chilling injury will occur. Symptoms of chillinginjury include irregular ripening and off flavor.

Sell tomatoes within 2–3 days for best flavor andquality. Good quality can be preserved for up to2 weeks if tomatoes are stored in a cool location,above 55°F and in 85–90% humidity. Mature greentomatoes may be stored for up to 6 weeks under sim-ilar temperature and humidity conditions.

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Classification Description Days to full color

Green fruit gelatin around seed has formed, skin is a whitish green 9–13

Breaker trace of color on blossom end 8

Turning 10–30% pink starting at blossom end 7

Pink 30–60% pink or red 6

Light red 60–90% pink or red 3

Red/firm ripe >90% red 1

Table ripe ready to eat, fruit somewhat soft 0

Canning ripe deep red but still firm 0

Soft ripe too soft to slice 0

PeppersHarvest peppers by hand when they are firm, tasty,and crisp. The plant will set more fruit after eachflush of harvest, so regular harvests maximize yields.Peppers grown for their red, purple, or yellow colormust ripen on the plant. Hot peppers will producethe strongest flavor if allowed to remain on the plantuntil fully ripe.

Peppers may be hydrocooled in a water bath toremove field heat. Dry them on a screen table andpack into waxed cardboard boxes. Maintain highhumidity and provide evaporative cooling by liningthe box with a clean damp cloth. Store peppers at45°–50°F with 90–95% relative humidity. Under theseconditions, peppers will keep for up to 2 weeks.Temperatures less than 45°F can cause the samechilling injury as in tomatoes.

Peppers such as chili or cayenne can be dried onscreen tables in a cool, dark, dry, well-ventilatedarea. Peppers can also be strung on thread throughthe stem and hung to dry. Dried peppers keep for upto 6 months at 60–70% relative humidity.

EggplantsHarvest eggplants by hand when they are glossyand deeply colored, 25–40 days after pollination,before the skin toughens and seeds become large

irrigation

R harvest, hand

ling, and

storage

Table 6. USDA tomato maturity classes

Harvesting&packing tips

When you harvest tomatoes, peppers, and

eggplants, change your position often to mini-

mize stress and fatigue to your body. You

might wear kneepads or sit on a small cart.

Use garden carts and wagons as much as

possible to minimize lifting and hand carrying

heavy produce. Standardized vented plastic

containers that stack are easy to load and

unload, and clean.

With a smooth level floor in the packing area, a

palletized packing and storage system can be

designed to fit small-scale operations (small

pallets moved with a hand-pulled pallet-jack)

or large operations (pallets moved by forklift).

Heavy boxes of produce can be moved from

one area to another on roller tables.

Layout your washing and packing area to mini-

mize stooping, lifting, and carrying. Set up

screen tables or water baths at table height.

Ideally, tables could be adjusted to match

each worker, so that work is performed at a

height between wrist and elbow.

12and bitter. High quality fruit should feel heavy in rela-tion to its size. Clip the fruit from the plant, leavingthe cap and part of the fruit stem intact. Wipe fruitclean but do not hydrocool it, since eggplant is verycold sensitive and cannot tolerate temperaturesbelow 50°F. Symptoms of chilling injury are pittedskin and internal flesh discoloration.

Pack eggplant in waxed cardboard boxes. Maintainhigh humidity by lining the box with a clean dampcloth. Optimum storage conditions are between55°–60°F at 85–90% relative humidity. Under theseconditions the fruit will maintain good quality for up to10 days. Otherwise, eggplants remain in top qualityup to 2 days.

Insect management

AphidsDescription: Aphids are small,soft-bodied, pear-shapedinsects that come in a variety ofcolors. They can be distin-guished from all other types ofinsects by the presence of corni-cles, or tailpipes projecting from

the back end of the insect.

The green peach aphids and potato aphids com-monly infest peppers. Both species can be wingedor wingless. The wingless forms can be up to 1⁄8 inchin length. The green peach aphid has an elongated,smooth, soft, spindle-shaped body. Antennae areheld to the side and are longer than the body.Coloration varies from green to reddish-pink. Wingedforms are a pale green. Potato aphids have moreslender bodies and longer legs and are more active.Both species have piercing/sucking mouthparts andfeed by sucking on plant juices.

Life cycle: In Wisconsin, green peach aphids over-winter as black eggs on the bark of peach, plum,apricot, or cherry trees and potato aphids overwinteras eggs on wild and cultivated roses. During thesummer, adult female aphids produce offspring with-out mating or laying eggs. In warm weather a femalecan give birth to as many as 12 nymphs per day.

Nymphs mature in less than 2 weeks. Late in the sea-son, the females mate and produce eggs which willoverwinter. Individual generations may be completedwithin 1 week during the summer, and multiple gen-erations overlap. Aphids produce winged offspringwhen colonies become overcrowded and when daylength begins to shorten. Colonies live primarily onthe underside of leaves, usually in the lower canopy.

Damage/Symptoms: Aphids feed by inserting a fine,needle-like stylet between plant cells into the vascu-lar tissue. Typically, this causes little direct injury toadjacent tissues. Extremely large populations mayextract enough sap to cause leaf curling and wiltingor eventual plant death. Seedlings are most suscepti-ble to aphid damage, although pepper plants of anysize may be killed by heavy aphid feeding. Aphidsexcrete excess sap, honeydew, which falls ontoleaves, giving them a sticky texture. Sooty mold fungimay grow on honeydew secretions, making affectedpepper fruit unmarketable. Both aphid species trans-mit potato virus diseases.

Management: Scout weekly for aphids by removingleaves from the mid to lower half of 25 plants persample site. Count the total number of adult andnymph aphids. Treat if you find more than 50 wing-less aphids per 25 plants early in the season or 100per 25 plants late in the season. Monitor whetherpopulations are increasing or decreasing over time.

Natural controls such as heavy rains, predators, anddiseases may help reduce aphid populations.Predators include ladybird beetles, lacewings, andsyrphid flies. Often, though, aphids reproduce farfaster than the parasites and predators can consumethem.

Systemic and foliar insecticides provide good con-trol. However, insecticides often also destroy thebeneficial natural enemies, resulting in secondaryaphid problems. In addition, many populations ofgreen peach aphids have high levels of insecticideresistance. Insecticides should be applied for otherinsects only when needed, as determined by scouting.

13Colorado potato beetle

Description: Adult Coloradopotato beetles have bright yel-low bodies with black stripesrunning the length of theirbacks and black spots behindthe head. They are 3⁄8 incheslong. Young larvae are smalland blackish-brown. Older lar-

vae are reddish-brown with black heads, legs, andspots along each side of their bodies. This beetleattacks potatoes primarily, but also causes severedamage to eggplant. Noncrop hosts include weedssuch as nightshade, ground cherry, jimsonweed,horse nettle, and mullein. If left unchecked, Coloradopotato beetle larvae and adultscan completely defoliate plants,resulting in reduced yield or plantdeath. Once a garden has beeninfested, potatoes and eggplantswill suffer progressively worsedamage in subsequent years.

Life cycle: Colorado potato beetles overwinter asadults in the soil. Adults become active in the spring.Females lay clusters of bright yellow-orange eggs onthe lower leaf surfaces. Larvae hatch 4–9 days laterand begin feeding immediately. They frequently con-gregate on new growth on the ends of stems. Larvaesoon turn brown-red, and although feeding damageon new growth is more evident, damage will not besevere enough to require treatment. Older larvaecause serious crop damage. Second-generationadults normally appear in mid-July and may causesevere defoliation. There are usually one to two gen-erations per year in most of Wisconsin.

Damage/Symptoms: Both adults and large larvae arevoracious leaf feeders, chewing holes larger than 1⁄8inch in diameter. Often, entire leaves on the tips ofplants are consumed. Larvae typically feed in groupsand may completely defoliate plants. Older larvae dothe most feeding damage. Heavy defoliation willseverely reduce plant yields.

Management: Begin monitoring eggplants forColorado potato beetles as soon as plants havebeen set out or when potato plants in nearby fieldshave emerged. Examine the lower leaf surfaces for

clusters of the bright yellow eggs. In areas that wereinfested the previous year, look for adult beetles onplants near field edges in early May.

Several cultural methods will help reduce the numberof Colorado potato beetles. This pest has a limitedhost range, so rotating out of solanaceous plantssuch as eggplant and potatoes, while also removingalternate host weeds, will effectively reduce beetlepopulations. Another technique is to plant strips ofearly-planted potatoes, trap crops, on field edgesnext to overwintering sites to attract beetles. Whenadults gather in these trap crops, use propaneflamers or vacuum suction to remove the beetles.Watch populations on plants over several days.Control when populations appear to have peaked. Athird strategy is to use physical barriers, such as rowcovers or plastic-lined trenches, to prevent adultbeetles from finding plants and laying eggs. Coverplants with row covers immediately after transplant-ing and keep covers in place until mid-June. Orplace plastic-lined trenches between fields and over-wintering sites before transplanting. In small planti-ngs, the large larvae and adults may be hand pickedor removed with a net. Colorado potato beetles con-tain a chemical that can burn and blister sensitiveskin, so be sure to wash your hands after handlingthe beetles.

Pesticide resistance is a serious threat to continuedeffective control of Colorado potato beetles. Certainraces of this pest are resistant to every class ofinsecticide currently registered for control. Bacterialinsecticides, such as Bacillus thuringiensis (Bt), areeffective against young larvae only; eggs, older lar-vae, and adults will be unharmed. Bacterial insecti-cides only persist 1–2 days and should be appliedweekly for 2–3 applications if used alone. OnlyBacillus thuringiensis-tenebreonis (Btt) is effectiveagainst Colorado potato beetles. The more com-monly available Bt-kurstaki (Btk), which is effectiveagainst lepidopterous larvae, will have no effect onbeetles. Refer to Commercial Vegetable Productionin Wisconsin (A3422) for a complete listing of avail-able insecticides.

insect manag

ement

1414European corn borer

Description: Europeancorn borers can causesignificant damage topepper crops. Theadult European corn

borer is a night-flying moth. Males are mottled brownand have a wingspan of about 1 inch. The femalesare lighter in color and slightly larger than the malesbut have the same markings. The larvae are 3⁄4–1inch at maturity and gray to cream-colored with manydark spots covering the body.

Life cycle: The European corn borer overwinters asmature larvae in corn stalks and stems of weedhosts. They complete development and pupate inthe spring when temperatures exceed 50°F. Peakmoth emergence for the overwintering generation isusually in June in southern Wisconsin. Shortly afteremergence, females mate and lay eggs over thecourse of a few evenings. The eggs hatch in 3–7days and the larvae begin feeding. There are twogenerations in southern Wisconsin and only one inthe northern part of the state.

Damage/Symptoms: European corn borers damagepeppers by tunneling into developing fruit and plantstems. The larvae feed inside the fruit for about 3weeks. Infested fruit often ripen earlier than the restof the crop. The second generation, which appearsin late July and early August, poses the most seriousthreat to peppers.

Management: To help control corn borer infestationsin peppers, keep pepper plantings as far away fromsweet corn fields as possible and remove grassyweeds from field edges. If you plan to use insecti-cides, you’ll need to time applications to coincidewith the peak moth flight and egg-laying period.Once larvae burrow into the fruit, they are protectedfrom insecticide sprays. The Department ofAgriculture Trade and Consumer Protection (DATCP)provides weekly reports during the growing seasonon corn borer populations or you can monitor themthrough blacklight trapping. This information will helpyou know when to look for moths in the grassy areas.Corn borers can often be successfully controlled withthree treatments made at 7-day intervals.

Flea beetlesDescription: Flea beetles are small(1⁄10 inch), dark beetles with largehind legs for jumping. Commonspecies in Wisconsin include theeggplant flea beetle, tobacco fleabeetle, potato flea beetle, and thepale-striped flea beetle. All attackeggplant but the pale-striped flea

beetle is most common on pepper while the eggplantflea beetle is most common on eggplant. Flea beetlefeeding can severely damage eggplants. Tomatoesand peppers often tolerate feeding once they havepassed the seedling stage.

Life cycle: Flea beetles overwinter as adults in leaf lit-ter, hedgerows, windbreaks, and wooded areas. Thebeetles emerge in late April when temperaturesreach 50°F. Adults begin laying eggs in the soil at thebase of host plants (eggplants, peppers, tomatoes,potatoes) in May. Eggs hatch 7–14 days later andlarvae feed on various plant parts until full grown.The larvae move below ground to pupate, emerging11–13 days later as adults.

Damage/Symptoms: Characteristic flea beetle feed-ing damage is tiny holes or pitted areas scatteredthroughout the leaves. Eggplants can be totally defo-liated if flea beetles are allowed to feed unchecked.

Conservation of natural enemiesNot all insects are pests. Beneficial insects prey on other

insects, helping to keep populations in check.You can take advantage of this free nat-ural resource by minimizing the use ofbroad-spectrum insecticides. For moreinformation about biological controls,

see Extension publication Biological Controlof Insects and Mites: An Introduction to Beneficial

Natural Enemies and Their Use in PestManagement (NCR481).

Management: Because flea beetles overwinter inplant debris, it is important to remove infested plantmaterial or incorporate it deeply into the soil at theend of the growing season. Floating row covers canbe used to protect eggplants. Row covers should beput into place when transplants are set out. Beginmonitoring for flea beetles as soon as the plants areset out. Treat if flea beetle populations exceed thethresholds listed in table 7.

LeafhoppersDescription: Leafhoppers are small(1⁄8 inch), wedge-shaped, slendergreen insects that feed on manyvegetable crops but primarily causeproblems on snap beans, potatoesand eggplants. Adults are extremelyactive and jump, fly or crawl side-ways or backwards when disturbed.

Life cycle: Potato leafhoppers don’t overwinter inWisconsin. Instead, they are blown north on windcurrents each spring. Large influxes of migrants inJune and early July cause populations to increaserapidly and seemingly “explode” overnight. Adultfemales insert white eggs into the stems or large leafveins of susceptible crops. Each female lays approx-imately three eggs per day for about 1 month. Eggshatch in 7–10 days. Nymphs develop in 12–15 days,maturing in late July. The second generation maturesin early September. There are normally two genera-tions per year in Wisconsin.

Damage/Symptoms: Like aphids, leafhoppers feedby sucking plant juices from the vascular tissue ofthe plant. Damage caused by leafhopper feeding iscalled hopperburn and results when the insectinjects a toxin with its saliva while feeding. Earlysymptoms appear as a yellowing of the leaf margins.Affected tissue later becomes brown and dry.

Management: Leafhoppers are difficult to controlbecause they are highly mobile. The best method ofleafhopper management is exclusion. Floating rowcovers will prevent leafhoppers from reaching theplant. Row covers should be set out when trans-plants are set into the field. Monitor leafhopper activ-ity in nearby field edges or other crops to determinewhen activity has dropped and row covers may beremoved.

Tomato fruitworm (corn earworm)Description:The tomatofruitworm isalso known asthe corn ear-

worm. This pest poses a more serious problem insweet corn production than in tomatoes or pepperswhere it is a sporadic pest. The adult fruitworm is atan moth with dark spots on the outer edges of theforewings and a wingspan of 11⁄2 inches. Newlyhatched larvae are light green to brownish-black withsplotches of pink, maroon, green, brown, or tan.Lengthwise stripes are characteristic on these lar-vae. Older larvae have the same coloration but takeon a “greasy” appearance. They are 13⁄4 inches longat maturity.

Life cycle: Most tomato fruitworms overwinter aspupae in the south. Adults emerge in the spring andmigrate northward. The moths fly mainly at dusk orduring warm, cloudy days. The moths typically arrivein southern Wisconsin in late July although timingcan vary depending on weather conditions. Whensusceptible sweet corn is not available, femalemoths are attracted to reproductively mature tomatoplants. They lay eggs singly near the fruit. Each fertil-ized female can lay up to 1000 eggs during her life-time. Larvae hatch as soon as 24 hours later in warm

15insect m

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Plant size Threshold (flea beetles/plant)

<3 inches 2

3–6 inches 4

>6 inches 8

Table 7. Treatment threshold for flea beetles on

eggplants

weather. After feeding for approximately 2 weeks, thelarvae drop to the ground and pupate. There is onegeneration per year.

Damage/Symptoms: Damage is more severe on lateplantings of tomatoes and peppers. The larvae prefergreen fruit and rarely enter ripening fruit. Feedingdamage creates deep, watery cavities. These cavi-ties are often colonized by soft-rot organisms makingdamaged fruit unmarketable.

Management: The tomato fruitworm can be monitoredwith the Hartstack pheromone trap. Growers withlarge plantings of tomatoes or peppers should set upand monitor their own traps. Small-scale growersmay consult pest report newsletters late in the grow-ing season to determine when the adult moths havereached the state and the activity of this insect insweet corn. Control is recommended if tomato andpepper fruit is present at the same time as the mothsare active. The bacterial insecticide, Bacillusthuringiensis (Bt) is recommended for controlling theearly stages of this insect. Treat when you find younglarvae on the fruit.

Tomato and tobacco hornworms

Description: Tomato hornworms and tobacco horn-worms are large (3–4 inches), blue-green caterpillarswith a characteristic horn on the tail end of the body.They feed on tomato leaves and occasionally on fruit.The adults are large, heavy-bodied hawk moths witha wingspan up to 5 inches, that become active in July.

Life cycle: Hornworms overwinter as pupae in thesoil. Adults emerge in late June and mate. Femalemoths lay pale-green eggs singly on the lower leafsurface of tomato plants. Upon hatching, the larvaebegin feeding immediately and may reach full sizewithin a month. In late summer, the fully grown larvaedrop from the plant to pupate in the soil. There is onlyone generation per year.

Damage/Symptoms: Infestations of the tomato ortobacco hornworm are usually localized and damageis rarely economically important in Wisconsin.

Management: Monitor fields frequently for damage.Fresh-market tomatoes should be treated if you findone or more caterpillars per two plants.Trichogrammid wasps offer natural control by para-sitizing hornworm eggs. The bacterial insecticide,Bacillus thuringiensis (Bt), is recommended for con-trol of young caterpillars.

16

Disease management

Early blightHosts and severity: Early blight is a potentially seri-ous disease that affects the leaves, stems, and fruitof tomatoes and eggplant. It is caused by the fungusAlternaria solani. Early blight typically occurs alongwith Septoria leaf spot.

Disease cycle: The fungus overwinters on infectedplant debris, on seed, or in the soil. It can survive for1 year on infected debris. Periods of warm, wetweather in the spring favor infection. Early-maturingtomato cultivars are the most susceptible to infection.

Symptoms: Leaf spots appear first on the olderleaves. The lesions spread out in concentric ringsenlarging to 1⁄4–1⁄2 inch in diameter. A yellow halomay surround the spots. In serious infections, entireleaves may yellow and drop off. As the plant defoli-ates, the fruit becomes exposed to the sun and issusceptible to sunscald. Infected fruit has dark,leathery, sunken spots near the stem end. Onlygreen fruit is infected.

Management: Early blight can be managed by prac-ticing crop rotations of 3–4 years out of any solana-ceous crop or by using pathogen-free seed. Severaltomato cultivars are tolerant of early blight, but onlyJubilee is recommended for Wisconsin. Protectivefungicides applied on a 7–10 day schedule will pre-vent the spread of infection.

Late blightHosts and severity: Late blight (Phytophthora infes-tans) is a fungal disease of tomatoes. It occurssporadically in Wisconsin but can be serious whenpresent.

Disease cycle: Late blight overwinters on infectedplant debris. Under cool, wet conditions, the diseasedevelops. Storms can carry spores of the fungusgreat distances, causing new outbreaks of the dis-ease in previously disease-free areas.

Symptoms: Late blight can affect all above-groundparts of the tomato plant. Early symptoms includewater-soaked spots that enlarge to cover the entireleaf. As the disease progresses, leaves becomebrown and shriveled. There may be a white, fuzzygrowth on the lower surface of infected leaves in wetweather. Fruit lesions are dark, olive green, greasyspots that may enlarge to cover the entire fruit. Softrots often follow late blight fruit lesions. One charac-teristic of late blight is the foul odor emitted by thedecaying vines.

Management: To manage late blight, practice a 2–3year rotation out of solanaceous crops. Destroyinfected plants immediately, including any potatotubers which may be infected. Copper fungicidesmay be used as a protectant if conditions favor dis-ease development. Tomato cultivars resistant to lateblight include Johnny’s 361, Red Currant, and YellowCurrant.

Septoria leaf spotHosts and severity: Septoria leaf spot is a seriousdisease that often occurs with early blight. This dis-ease, caused by the fungus Septoria lycopersici,can infect tomatoes and ground cherries as well asjimsonweed and nightshade. Septoria often occursalong with early blight.

Disease cycle: Septoria overwinters on weedy hostsor on infected plant debris for up to 3 years. Wetweather favors infection. Infection begins on thelower part of the plant. It spreads upward as sporesfrom infected leaves are splashed onto clean foliageby rain or irrigation water. Spores can also be spreadif field work occurs while plants are wet.

Symptoms: Initially, small, circular spots appear onthe upper surfaces of older leaves with water-soakedareas on the lower leaf surface. Infection does notoccur until after fruit set has begun. As the spotsenlarge, they develop dark brown margins withsunken gray centers. Tiny black fruiting bodies maybe found in the center of these lesions. Infectedleaves often drop from the plant, exposing the fruit tosunscald.

17d

isease manag

emant

Management: To manage this disease, plow underinfected debris immediately after harvest in the fall.Do not compost infected plants. Rotate out of solana-ceous crops for 3–4 years and control solanaceousweeds. Protectant fungicides may be applied to pre-vent the disease from spreading. There are no resis-tant cultivars commercially available.

Fusarium and Verticillium wiltsHosts and severity: Two fungal pathogens cause wilt-ing of tomato plants, Fusarium oxysporum f.sp.lycopersici and Verticillium dahliae. The fungus thatcauses Fusarium wilt is specific to tomatoes whileV. dahliae may attack hundreds of plant speciesincluding peppers and eggplants.

Disease cycle: Both fungal organisms are soil-borne.High soil moisture and high temperatures favor initialinfection.

Symptoms: The early symptoms of both diseasesbegin as a yellowing of the older leaves. Often, onlythe leaves on one side of the plant are affected. Thesymptoms progress up the stem until much or all ofthe plant dies. Cutting open an infected stem, wherethe leaf petiole is attached, will reveal a dark browndiscoloration. If you suspect Fusarium or Verticilliuminfections, send or bring a sample to your countyExtension office for diagnosis.

Management: These diseases are soil-borne andlong-lived. Therefore, it is important to rotate out ofsolanaceous crops for at least 3–4 years. If plantingin a field with a history of either disease, select aresistant variety. Resistant varieties includeBeefmaster, Better Boy, Campbell 1327, Celebrity,Flash, Floramerica, Heinz 1350, Jet Star, Lemon Boy,New Yorker, Pole King Hybrid, Roma VF, Small Fry,and Viva Italia. Currently, no eggplant cultivars areresistant to Verticillium or Fusarium and very fewpeppers are resistant to Verticillium.

Bacterial speck and bacterial spot Hosts and severity: These two diseases are oftenfound together on the same plant but may occurseparately. They may occur on both tomatoes andpeppers.

Disease cycle: Bacterial speck is caused byPseudomonas syringae and is often seed-borne.Bacterial spot is caused by Xanthomonas campestrisand overwinters on infected plant debris. Both dis-eases are spread by splashing water. Working in thefield while plants are still wet hastens spread of thediseases. Warm weather favors the development ofbacterial spot while cooler weather tends to producebacterial speck infections.

Symptoms: Bacterial speck produces small (less than1⁄8 inch diameter), dark, round lesions on leaves.Initially, the lesions are surrounded by a yellow halo.As the disease progresses, the lesions may spreadto stems, petioles, and flowers. On fruit, tiny darkspots develop. Fruit lesions are often sunken with adarker green halo surrounding the center of thelesion. Bacterial spot produces water-soaked, brownlesions on all above-ground plant parts. A yellowhalo surrounds the lesions. As the disease becomesmore severe, a generalized yellowing may occur onthe leaves.

Management: Both bacterial diseases can be con-trolled by rotating fields out of solanaceous crops forat least 2 years. Using treated seed will preventseed-borne infection. Reduce activity in the fieldwhen plants are wet. Copper-containing pesticidesare available for use in controlling bacterial spot.There are a few resistant pepper cultivars, but theyhave not performed well in Wisconsin.

18

AnthracnoseHosts and severity: Anthracnose is a common dis-ease of tomato and pepper fruit. Infection occurswhen the fruit is still green but symptoms don’tappear until the fruit begins to ripen.

Disease cycle: Anthracnose overwinters in the soiland on infected plant debris. Warm weather alongwith free water favor infection. Fruit that comes incontact with soil is most likely to become the initialpoint of infection.

Symptoms: This disease produces small, round,slightly sunken spots that are surrounded by concen-tric rings. Leaves, stems and roots may be infected.

Management: Prevention is the best control. Croprotations out of solanaceous crops for 2–3 years willreduce the incidence of disease. Weed managementpractices to control susceptible weeds will reducereservoirs of the disease. Cultural practices such asmulching and staking to prevent the fruit from com-ing in contact with the soil will also reduce thechance of infection. Using drip irrigation, rather thanoverhead irrigation, will also reduce spread of thedisease. In severe outbreaks, fungicides may benecessary to protect developing fruit.

Viruses Hosts and severity: Several viruses can affect theproduction of tomatoes, peppers, and eggplant.Three common viruses are tobacco mosaic, cucum-ber mosaic, and spotted wilt viruses. All viruses canweaken infected plants and reduce yield and quality.

Disease cycle: Tobacco mosaic virus is spread pri-marily through infected seed and by human activity.Cucumber mosaic virus is transmitted by aphids andhas a wide host range including carrot, celery,cucurbits, eggplants, legumes, lettuce, pepper,spinach, and tomato. Because the host range is sobroad, cucumber mosaic virus is often difficult to

control once it becomes established in weedy reser-voirs. The tomato spotted wilt virus is transmitted bythrips and causes a bronzing of the young leaves.

Symptoms: Symptoms of each virus are characteris-tic of that virus. Tobacco mosaic virus produces mot-tled tissue on foliage and fruit. Affected leaves maybecome distorted, twisted or strap-like, mimickingsymptoms caused by phenoxy herbicides. Fruitsinfected with tobacco mosaic virus usually ripenunevenly and are smaller in size and number thantheir healthy counterparts.

Cucumber mosaic virus also produces shoestringfoliage. Early symptoms of the disease are yellow,bushy, and stunted foliage. The oldest and youngestleaves may show symptoms while the middle part ofthe plant appears normal. Severely infected plantshave reduced yield.

In plants infected with tomato spotted wilt virus,leaves develop numerous small, dark spots. Shootsmay wilt and die and infected stems are oftenstreaked. On infected fruit, target-shaped lesionsappear. These areas become more pronounced onripe fruit.

Management: Virus diseases are best managedthrough prevention: use resistant cultivars and followgood sanitation practices such as planting cleanseed and eliminating weed hosts. Do not smokewhile you work with tomato plants since viral dis-eases may be carried on your hands from tobacco.

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ement

20Environmental disorders

Blotchy ripeningBlotchy ripening of tomatoes is characterized byareas of the fruit that fail to ripen properly because ofpoor fertilization. This problem is more prevalent incool years and is exacerbated by too much or too lit-tle water. The symptoms may also appear on virus-infected plants. Yellow or orange blotches appear onthe surface of ripening fruit while the tissue insideremains hard and white. The affected area is usuallyon the upper portion of the fruit. Blotchy ripening iscultivar specific and appears more frequently on oldercultivars.

CatfacingCatfacing describes the presence of deep indenta-tions in the blossom end of the fruit. This damageoccurs when temperatures drop below 50°F duringflowering and fruit set. In some cases, excess heat,2,4-D injury, and erratic soil moisture can lead to cat-facing. Large-fruited cultivars are most susceptible.Catfacing is cultivar specific and appears more fre-quently on older cultivars.

Growth cracksTwo types of growth cracks affect the stem end oftomatoes: concentric and radial. Concentric crackingproduces circular cracks around the stem end of thefruit. Radial cracks spread outward from the stemscar. These cracks typically appear as the fruitmatures. Growth cracks often appear when conditionsdrastically change the rate of growth, such as widefluctuations in temperature and moisture. Dry weatherfollowed by heavy rains typically causes radial crack-ing in many tomato cultivars. Cultivars vary in theirability to withstand cracking depending on thestrength and “stretchability” of the skin. Proper plantnutrition and adequate, regular irrigation will reducethe likelihood of growth cracks.

Green shoulderGreen shoulder is similar to blotchy ripening, but onlythe shoulder region of the fruit remains unripe. Itresults when the chlorophyll in the affected area failsto break down as it does during the normal ripeningprocess. Green shoulder is cultivar specific. If itoccurs over several years, select a cultivar that is lesssusceptible to this disorder.

Large core or puffinessThis disorder produces angular tomatoes. If cut open,affected fruit have locules (chambers) that did not fillwith gel, causing the fruit to become flattened. Poorpollination, excess nitrogen, and improper seeddevelopment can cause large core. Cold tempera-tures may worsen the disorder. Many cultivars aresusceptible.

Physiological leaf rollPhysiological leaf roll can occur on any tomato culti-var and is most severe during excessively cold, wetyears. High water pressure within the plant causes themargins of the leaves to curl upward. This disordermay be mistaken for leafhopper damage, althoughleaves do not have marginal browning. It has no affecton fruit production.

Sun scaldSun scald is characterized by bleached, sunken tis-sue on the fruit. It occurs when the plant is defoliatedby disease, exposing the fruit to direct sunlight.Peppers, staked tomatoes, and determinate tomatoesare more susceptible to sun scald. Secondary rotorganisms often invade the affected tissue causingsubsequent fruit rots.

Weed managementWeed management is essential for crops to producemaximum yields. Weeds compete with crop plantsfor sunlight, water, nutrients, and space. Beforeplanting, reduce perennial weed populations bysmothering with a cover crop (such as buckwheat),by solarization with black plastic, by hand removal,or by using herbicide sprays. Cultivate or hoe regu-larly to control annual weeds.

Black plastic mulch within rows makes a good weedbarrier, helps warm the soil in the spring, and pre-vents the spread of some diseases. A thick strawmulch will prevent weed germination and growth byblocking sunlight from reaching the soil. Between therows, cultivation and herbicides will control weedsnot smothered by the plastic mulch. Some of theproblematic weeds that occur in solanaceous cropplantings include nightshade, pigweed, lambsquar-ters, smartweed, morning glory, annual and peren-nial grasses, green foxtail, and nutsedge. There arecommercially available cultivars of tomato that areresistant to the herbicide metribuzin allowing the useof this herbicide without injury to the plants.

Additional reading

CultureCommercial Greenhouse Production: Tomatoes.William J. Lamont Jr. and Charles W. Marr. KansasState Extension.

Direct Marketing of Farm Produce and HomeGoods—Direct Marketing Alternatives and Strategiesfor Beginning and Established Producers (A3602).John Cottingham, James Hovland, et al. 1994.University of Wisconsin-Extension.

Growing For Market Newsletter. FairplainPublications, P.O. Box 3747, Lawrence, Kansas66046. A monthly newsletter with practical articles onall aspects of small-scale fresh market farming,

Harvesting Vegetables from the Home Garden(A2727). H.C. Harrison. 1996. University ofWisconsin-Extension.

21environm

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weed

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Knotts Handbook for Vegetable Growers, FourthEdition. Donald N. Maynard and George J.Hochmuth. 1997. Wiley.

The New Organic Grower. Second Edition. . EliotColeman. 1995. Chelsea Green Publishing.

The New Seed Starters Handbook. Nancy Bubel.1988. Rodale Press.

Soil Test Recommendations for Field, Vegetable, andFruit Crops (A2809). K.A. Kelling, L.G. Bundy, S.M.Combs, and J.B. Peters. 1998. University ofWisconsin-Extension.

Storing Vegetables at Home (A1135). H.C. Harrison.1996. University of Wisconsin-Extension.

Rodale's All New Encyclopedia of OrganicGardening. Edited by Fern Marshall Bradley andBarbara W. Ellis.1992. Rodale Press.

World Vegetables: Principles, Production, andNutritive Values. Second Edition. Vincent E. Rubatzkyand Mas Yamaguchi. 1997. Chapman and Hall.

PestsBiological Control of Insects and Mites: An introduc-tion to Beneficial Natural Enemies and Their Use inPest Management (NCR481). Daniel L. Mahr andNino M. Ridgway. 1993. University of Wisconsin-Extension

Commercial Vegetable Production in Wisconsin(A3422). L.K. Binning, C.M. Boerboom, et al.Updated annually. University of Wisconsin-Extension.

Disease-Resistant Vegetables for the Home Garden(A3110). D.E. Brown-Rytlewski, M.F. Heimann, et al.Updated annually. University of Wisconsin-Extension.

Identifying Diseases of Vegetables. A. A. MacNab, A.F. Sherf, and J.K. Springer. 1983. Pennsylvania StateUniversity College of Agriculture.

Pests of the Garden and Small Farm: A Grower’sGuide to Using Less Pesticide. Mary Louise Flint.1990. University of California, publication #3332.

Rodale’s Color Handbook of Garden Insects. AnnaCarr. 1979. Rodale Press.

Vegetable Insect Management with Emphasis on theMidwest. Rick Foster and Brian Flood, editors. 1995.Meister Publishing Company.

Weeds of the North Central States. North CentralRegional Research Publication No. 281. 1981.University of Illinois at Urbana-Champaign, Collegeof Agriculture.

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Copyright © 1997 University of Wisconsin-System Board of Regents and University of Wisconsin-Extension, Cooperative Extension.

Authors: K.A. Delahaut is horticulture outreach specialist for the Integrated Pest Management Program, College of Agriculturaland Life Sciences, University of Wisconsin-Madison and University of Wisconsin-Extension, Cooperative Extension.A.C. Newenhouse is horticulture outreach specialist for the Wisconsin Healthy Farmers, Healthy Profits Project of the depart-ment of Biological Systems Engineering, College of Agricultural and Life Sciences, University of Wisconsin-Madison. Producedby Cooperative Extension Publishing, University of Wisconsin-Extension.

University of Wisconsin-Extension, Cooperative Extension, in cooperation with the U.S. Department of Agriculture and Wisconsin coun-ties, publishes this information to further the purpose of the May 8 and June 30, 1914 Acts of Congress; and provides equalopportunities and affirmative action in employment and programming. If you need this material in an alternative format, contactthe Office of Equal Opportunity and Diversity Programs or call Cooperative Extension Publishing at 608-262-8076.

This publication is available from your Wisconsin county Extension office or from Cooperative ExtensionPublishing, Rm. 170, 630 W. Mifflin St., Madison, Wisconsin, 53703. Phone 608-262-3346. Please call for publication availability before publicizing.

A3685 Growing Tomatoes, Peppers, and Eggplants in Wisconsin: A Guide for Fresh-Market Growers

I-12-97-2M-500

Partial funding for the printing of this publication was through a grant from the Wisconsin Sustainable Agriculture Program.