A3686

K.A. DelahautA.C. Newenhouse

Growingcarrots, beets,radishes, andother root cropsin WisconsinA guide for fresh-market growers

ContentsPlant description, 1

Site selection, 3

Cultivar selection, 3

Planting and culture, 5

Soils and nutrient management, 7

Irrigation, 9

Harvest, handling, and storage, 10

Insect management, 11

Disease management, 15

Weed management, 18

Additional reading, 19

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).

s

1

Market gardeners typically growseveral root crops in Wisconsin.The flavor of fresh, locally growncarrots far surpasses supermar-

ket carrots. Carrots are becoming morepopular as the role of beta carotene inhuman health is understood. Carrotscontain a high amount of beta carotene,a precursor to vitamin A. Vitamin A helpsprevent infection, may prevent some

forms of cancer, and improves vision.Carrots are the main dietary source of vita-

min A in the United States. They also con-tain vitamin C, thiamine (B1), and riboflavin

(B2). Beets provide a multiseason crop forfresh market beginning with early salad

greens, followed by early beets, and later stor-age beets. Radishes are popular in salads and

provide market gardeners with an early seasoncrop. Other root crops such as parsnips, turnips, andrutabagas may be profitable in niche markets.Properly stored root crops can extend the fresh-mar-ket vegetable season into late fall in Wisconsin.

Although carrots, beets, radishes, parsnips, turnips,and rutabagas are very different botanically, theyshare similar growth requirements such as soil typeand cultural practices.

Plant descriptionBotanically, the part of the plant that we eat in all ofthe crops discussed in this publication is theenlarged stem below the seed leaves (the hypocotyl).There are feeder roots along this structure and a tap-root below. In this publication the term “root” for rootcrops will refer to the edible hypocotyl portion. Thevegetables fall into three plant families: Umbelliferae,Chenopodiaceae, and Cruciferae.

CarrotsCarrots, Daucus carota var. sativus, belong to theUmbelliferae family. Red carrots were originally culti-vated over 2000 years ago as medicinal plants inmiddle Asia. Red carrots remained the standard untilthe 17th century when white, purple, yellow, andorange varieties were selected. These colors are still

found in carrots grown in some areas of Europe andAsia, although orange has become the standard inthe United States.

Carrots are biennials. They form a rosette of herba-ceous leaves and the edible root the first year. If leftin the ground the second year, carrots produce ashort branched seed stalk which bears an umbeltype of flower cluster. Queen Anne’s lace is a wildform of carrot and produces the typical carrot flower.Carrot flowers are white and contain both male andfemale parts. Honey bees are the main pollinator.Flowers are produced after the plant has beenexposed to temperatures below 50°F for 6–8 weeks.Long day conditions can accelerate flowering. Underheat or moisture stress a flower stalk maydevelop during the first year. Stored sug-ars then break down and move from thecarrot root to the flower which causes car-rots to become woody and inedible.

Carrot seed leaves(cotyledons) are strap-like. True leaves arefern-like and doublycompound. Carrotroots arecomposedof four dis-tinct sec-tions: peel orperiderm, cortex(comprised of thephloem, or food-con-ducting tissue), cam-bium, and the centralcore (comprised ofxylem, or water-conduct-ing tissue). Sugar andcarotene are concen-trated in the cortex.

plant d

escription

Figure 1. Parts of a carrot root

crown

cortex(phloem)

central core (xylem)

secondaryroot

peel (periderm)

cambium

2ParsnipsParsnip, Pastinaca sativa, is also a member of theUmbelliferae family. Parsnips are native to theMediterranean. Parsnips resemble long, white,tapered carrots, and have high niacin levels similar tocarrots. Like carrots, parsnips are hardy biennialsalthough they are treated like slow-growing, cool-sea-son annuals. After planting in spring, they are har-vested in late fall of the first year or early spring of thesecond year, before the plant begins to flower.Parsnip leaves are pinnately compound with smallerupper leaves attached directly to the stalk. Flowersare umbels with both male and female parts. Theyare pollinated by bees and blow flies.

BeetsBeets, Beta vulgaris, are grown for both their edibleroots and greens. This publication will discuss beetroot production. Beets belong to theChenopodiaceae or goosefoot family, along withSwiss chard, spinach, celery, and parsley. Beets orig-inated in western Europe and north Africa where theywere grown to feed both humans and livestock. Beetscontain alternating light and dark bands or zones ofphloem and secondary xylem. This crop is a biennialgrown as a cool-season annual. During the first year,they produce a basal rosette of fleshy triangularleaves with long petioles, and the edible beet root. Ifplants are left in the ground the second year, a flowerstalk is produced. If beets are exposed to tempera-tures below 50°F for 2–3 weeks their first year theywill bolt and produce flowers. Flowers contain bothmale and female parts and are borne in a panicle.Thrips pollinate beet flowers. After pollination, a corkyseed ball develops which contains one or more fruitwith two to five seeds each. Beets contain a deep red

pigment (betacyanin) and a yellowpigment (betaxanthin). They are

high in carbohydrates.

RadishesRadishes, Raphanus sativus, belong to theBrassicaceae family (cole crop family). Like otherbrassicas, radishes contain mustard oils, which givethem pungency. Radishes were originally cultivatedin China. There are quick-growing spring typeradishes and slow-growing summer and winterradishes. Daikons are a long white Asian type of win-ter radish. Radishes may be grown as a cool-seasonannual sown in the spring and early summer, or as abiennial if sown in fall. Radish leaves are deeply pin-nate and form a basal rosette. Most radishes producea flower stalk the second year, after cool tempera-tures followed by long days initiate bolting. Floweringor bolting in annual radishes can occur after rootsreach edible size and the plant is exposed to warmtemperatures. Once the plant produces a flowerstalk, radish flavor and quality deteriorate. Rose orwhite flowers are borne in an elongated raceme andhave the characteristic cross shape of brassicas.Radish flowers are insect pollinated.

Rutabagas and turnipsRutabagas, Brassica napus var. napobrassica, andturnips, Brassica rapa, also belong to theBrassicaceae family. Rutabagas and turnips are cool-season biennials native to Asia and Eurasia.Rutabagas, also called Swedes, are thought to haveoriginated from a cross between turnips and cab-bage. Rutabagas are large, round, and have solidyellow flesh. Their leaves are smooth, fleshy andlarge, and grow from a short stem, unlike turnip.Rutabagas contain carotenes which are a precursorto vitamin A, although carotene levels are low com-pared to carrot.

Turnips are smaller than rutabagas and can beround, flattened, or elongated. The flesh is white.Turnip leaves are hairy, thin, smaller than rutabagaleaves, and are used as greens. This crop requires ashorter growing season than rutabagas. Rutabagasand turnips form yellow flowers in a raceme the sec-ond year. Both flowers readily cross pollinate, butturnips require cross pollination to produce seedwhereas rutabagas are self-fertile. If rutabagas areexposed to temperatures below 50°F for 3–6 weeksflowers are induced. When flower production begins,root flavor and quality deteriorate.

Site selectionChoose a sunny site with deep, friable soil for rootcrops. Soils may range from organic muck soils tosandy loams. A compaction layer or shallow plowpan will hamper root growth. Root crops grow beston fluffy soils with good tilth. Root crops can toleratea wide pH range. Carrots, parsnips, and rutabagasgrow well in pH 5.5–7.0, radishes in 6.0–7.0, andbeets in 6.0–7.5.

Cultivar selectionRefer to table 1 for a list of some suggested root cropcultivars for Wisconsin.

CarrotsCarrots are grouped according to shape and marketuse into four classes: Imperator, Nantes, Chantenay,and Danvers. Imperator carrots are grown for freshmarket sale and sold either in bunches with their topsor in bulk without. Imperator carrots are long andtapered and have a deep orange cortex with a lighterorange core. Harvest Imperator carrots before theymature and become woody. Nantes carrots are alsogrown for fresh market sale. They are bright orange,short, and cylindrical with a blunt, rounded base.Baby Nantes cultivars are only 1⁄2–3⁄4 inch in diameterand 21⁄2–3 inches long. They typically have a smallcore, sweet flavor, crisp texture, and high quality.Carrots of several cultivars can be harvested as babycarrots when immature. Chantenay carrots are short,tapered and are primarily for storage or processing.Chantenays are tender and crisp, and vary frommedium to light orange. Danvers carrots are longerthan Chantenay but are also short and tapered. Theirdeep orange flesh is often tinged with green. MostDanvers varieties are processed into baby food.

3site selection

Rcultivars

Carrots

Long A PlusImperatorIngotOrlando GoldSavoryScarlet Nantes

Half-long ArtistLucky BNantesNelson PioneerRed Cored Chantenay

Baby Little FingerMinicor

BeetsBig RedBurpee GoldenChioggia (striped)CylindraDetroit Dark RedDetroit SupremeLutzRuby Queen

(bunching type)

Radishes

Spring typeCherry BelleEarly Scarlet Globe

Summer typeFrench Breakfast Snow Belle (white)White Icicle (white) Red Meat

Winter typeApril Cross Round Black Spanish

ParsnipsLancerHarris ModelAndoverAll America

Rutabagas American Purple TopLaurentianYorkFortune

TurnipsPurple Top White GlobeGolden BallJust Right

Table 1. Recommended cultivars

Note: Choose cultivars according to your own situation and needs. Consider what your marketdemands, the length of your growing season, yoursoil, pests, diseases, irrigation, cultivars othergrowers like, and cultivars you personally like.When trying a new cultivar, do not use it exclu-sively. Grow new trials next to old standbys so youmay compare the characteristics objectively.

Carrot breeders have focused on producing sweetcarrots with high vitamin A content, deep orange-redcolor, and uniform size and shape. Disease resis-tance has also been a main focus of carrot breedingprograms. Cross breeding is necessary in carrots tomaintain plant vigor.

ParsnipsParsnips are bred for flavor, smooth long roots andcanker resistance. Lancer, Harris Model, Andover,and All America are recommended parsnip cultivars.

BeetsBeet cultivars are described by their color andshape. They may be red, yellow, purple, white orstriped, top-shaped, globe-shaped, flattened or elon-gated. Beets are also further classified by theirintended use, such as storage, slicing or bunching.Plant breeders select beets for taste, uniform colorbetween the xylem and phloem rings, and the pro-duction of one seed per fruit for more reliable seedspacing.

RadishesRadish cultivars are grouped according to the sea-son in which they will be grown. Cultivars may beclassified as spring, summer, or winter radishes.Spring radishes are globe-shaped and bright red,white, pink, or purple. They mature in only 25–30days. Summer radishes are similar to spring radishesbut are larger and slower to mature. Summer andwinter radishes require approximately 50–60 days tomature. Winter radishes favor cool temperatures andshort days and are grown as a fall crop in Wisconsin.Radish breeders select for taste, bolt resistance, dis-ease resistance, and appearance.

RutabagasRecommended rutabaga cultivars for Wisconsin areAmerican Purple Top, Laurentian, York, and Fortune.Breeders look for rutabagas resistant to clubroot dis-ease to which all brassicas are susceptible.

TurnipsPurple Top White Globe is a standard Americanturnip cultivar. Golden Ball is a yellow-fleshed, sum-mer cultivar. Just Right is an F1 hybrid with a large,smooth, white root. Plant breeders select for taste,production of hybrid vigor and uniform growth inturnips.

4

Figure 2. Carrot types, from left: Imperator,

Danvers, Nantes, and Chantenay

5Planting and cultureRefer to table 2 for the estimated amount of seedrequired, seed planting depth, yield, planting date,spacing, and days to first harvest.

In general, carrots, beets, turnips, and parsnips maybe planted around April 15 in southern Wisconsin.Growers in the northern part of the state should waituntil late April before seeding these crops. Seeds areoften treated with a fungicide to reduce the incidenceof seed-borne or soil-borne pathogens which causeseedling diseases.

Most root crops grow during spring or fall, whencooler night temperatures slow respiration and carbo-hydrates are stored in the roots. Long-season cropssuch as parsnips, turnips, and rutabagas are sown inthe spring and harvested in late fall or winter.

Soil preparationSeedbed preparation is the most important step ingrowing root crops. Soils must be rich, deep, and fri-able. Well-drained soils are essential to prevent soil-borne pathogens from infecting the plants. Use deeptillage to remove any plowpan compaction at a depth of6–8 inches. Before planting, remove clods, rocks, andplant debris to prevent irregular growth or stunting.

Raised beds. Raised beds are an alternative to theconventional field planting method, and are oftenused to improve carrot growth and shape. This plant-ing system improves soil drainage and allows accessto the crop without causing soil compaction. Raisedbeds are typically 4–5 feet wide and 100 feet long.The width is determined by the type of equipmentused and by the crop. Leave a 1-foot aisle on eitherside of each bed to accommodate foot traffic.

planting

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 3. 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

SeedingRoot crops are often precision seeded with mechani-cal seeders that prevent the need for subsequentthinning. Precision seeding requires specializedplanters and uniformly sized seeds. Specializedplanters are available such as the gravity-feed coneseeder, belt-driven seeder, and vacuum seeder.Walk-behind plate-type seeders are also used.Pelleted or coated seed is uniformly sized; it is avail-able for some root crops. Plantings are often irrigateduntil germination to prevent the soil from crusting andcausing uneven stands.

Carrot cultureCarrots grow best at 59°–65°F, where rapid growthpromotes good flavor. In warmer temperatures,coarse roots with poor flavor develop, and roots areshort and more blunt. Misshapen carrots form in soilwith stones or clods, and forked roots tend to form inheavy soils. On sandy soils or muck soils where blow-ing particles can shear tender germinating carrotseedlings, you can interplant strips of annual smallgrain crops such as oats to form a windbreak. Somegrowers will allow nearby grassy weeds to remainand act as a windbreak instead of planting a smallgrain. Windbreak effects typically extend to 21⁄2 timesthe height of the windbreak. For example, a 2-foot-tallwindbreak will reduce air flow up to 5 feet away onthe lee side. After the carrots have become estab-

lished, mow the grain seedheads or kill it with an her-bicide to prevent volunteer grain weeds. If youchoose herbicide applications, apply the first onebefore carrot emergence. This application won’t killthe grain crop but will reduce its vigor. Make a sec-ond herbicide application once the second set of trueleaves emerges from the carrot seedlings. When thethird true carrot leaf emerges, use a knockdown her-bicide to kill the small-grain nurse crop or the weedywindbreak.

Hoe or cultivate soil around the top part of carrotroots to prevent them from turning green in sunlight.Carrots are typically seeded in three rows per bedwith the seeds equidistant to each other. They canalso be planted 3⁄4–1 inch apart in 2-inch wide rows16–24 inches apart, or in single rows 15–30 inchesapart. Sow carrots 3 weeks apart to extend your har-vest season in spring and fall. Carrots can withstandmild frost and light freezes.

Parsnip cultureGrow parsnips under the same conditions as carrotsbut space them slightly farther apart since they growslightly larger than carrots (table 2). Parsnips growbest at 60°–65°F and cannot tolerate heat as well ascarrots can. Parsnips become sweeter after a late fallfrost.

6

Planting time Seeds Seed Spacing (inches) Days Estimated in southern WIa needed for depth between between to first yield (lb/ft

Vegetable outdoors 100 ft row (inches) rows plants harvestb of row)c

Carrot April 15 1⁄4 oz 1⁄4 15–30 1–3 60–70 1–11⁄2

Beet April 15 1–11⁄4 oz 1⁄2 15–30 2–4 50–60 1⁄2–11⁄2

Radish April 15 1 oz 1⁄2–3⁄4 8–18 1–2 25–30 1⁄2

Parsnip April 15 1⁄2 oz 1⁄2–3⁄4 18–36 2–4 100–120 11⁄2

Rutabaga June 15 1⁄8 oz 3⁄4 18–36 6–8 100–110 3

Turnip April 15 1⁄4 oz 1⁄2–3⁄4 12–36 2–6 40–70 2aPlant about 1 week later along the lower lake shore and in the central part of state and about 2 weeks later in northerncounties.

bCultivars 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.

c Estimated yields under less than ideal growing conditions; actual yields will vary widely with weather, soil fertility and cultural practices.

Table 2. Planting guide

7Beet cultureBeets produce their best flavor with rapid growth at55°–70°F. “Zoning,” or alternating dark- and light-col-ored rings, become visible in roots after severe tem-perature fluctuations. Plant seeds 2–4 inches apart indouble rows or in 2- to 4-inch bands. Space rows orbands 15–30 inches apart. Sow beets 2–3 weeksapart to extend your harvest season in spring andfall. Beets can tolerate mild frost and light freezes.

Radish cultureSpring radishes develop their best flavor if rapidgrowth with plenty of moisture occurs at 60°–65°F.Radish quality and flavor decline in warmer weather.Plant spring radish seeds 1 inch apart in rows 1 footapart. Plant winter radishes 2 inches apart in rows 18inches apart. Spring radishes can be planted inraised beds to encourage a rapid, complete plantcanopy that prevents weed growth. Since springradishes produce a crop so quickly, they can beinterplanted with slower growing crops such as latecabbage, peppers, or tomatoes.

Radishes can be planted before the last frost inspring. Sow radishes every 10–14 days in spring toextend your harvest, and repeat for a fall crop.

Rutabaga and turnip culturePlant rutabagas and turnips as late as possible tomature before a hard freeze, since both grow best incool temperatures. Both rutabagas and turnips cantolerate frost and light freezes. Plant rutabaga seeds6–8 inches apart in rows 18–36 inches apart. Plantturnips 2–6 inches apart in rows 12–36 inches apart.

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.

Root crops can be grown on a wide variety of soiltypes, but soil tilth characteristics are critical. Refer tothe site selection section on page 3 for a discussionof soils for root crops.

planting

and culture

Rsoils and nutrients

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. Organic fer-tilizers 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 of sourcessuch as manures, compost, fish meal, and bonemeal. Each material contains varying amounts ofspecific nutrients. Table 3 lists organic fertilizers andthe amounts of nutrients in each. For more informa-tion on this subject, refer to Extension publicationOrganic Soil Conditioners (A2305). Table 4 listsguidelines for nutrient management to compare withyour soil test results.

Fertilizer should be broadcast or applied in a band 2inches to the side of the row and 2 inches below theseed depth. On sandy soils, split nitrogen into two tothree applications over the course of the growingseason. Too much nitrogen on carrots, radishes, orparsnips will cause excessive top growth.

Carrots also need moderate amounts of manganese,boron, and copper. Carrots grown in copper-deficientmuck soils have poor color.

Test your soil for boron before growing beets. Beetsgrown in soils deficient in boron will develop blackspots in the phloem tissue and dry rot on the rootsurface. Boron deficiency is most common on cal-careous soils and under drought conditions. Someplants such as muskmelon and sweet clover accu-mulate boron, and their composted leaves may beadded to soil to raise soil boron levels. Excessiveboron in soils may cause poor beet seed germina-tion. Rutabagas are also susceptible to boron defi-ciencies and develop brown, water-soaked spots inthe core of the root.

Radishes need moderate amounts of boron, copper,manganese, molybdenum, and zinc. Soil test resultswill show recommendations to add zinc or to alter soilpH to make more molybdenum available.

8

Table 3. Nutrient composition of various organic fertilizers

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 the source.

IrrigationMoisture stress can reduce crop yield. If leavesbegin to wilt midday, plants are moisture stressed.Plants that wilt intermittently may produce smalleryields, while plants that wilt frequently or that wilt toolong often die due to irreversible cell damage.

Most root crops require irrigation prior to germinationto prevent a crust from forming on the soil whichimpedes germination. After germination, irrigation isonly necessary during drought or on typically drysoils such as sand. Both drip and overhead sprinklerirrigation systems are effective, such as trickle tape,solid set, and traveler hose wheel. Radishes requireadequate soil moisture to prevent them from devel-oping an overly pungent taste. Carrot yield is higherwith an even water supply, which can prevent crack-ing caused by wet weather immediately following dryweather. If you irrigate your soil, be sure to closelymonitor micronutrient levels to prevent deficiencies.

9irrig

ation

Table 4. Annual nitrogen, phosphate, and potash recommendations for root crops

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

Carrot <2 120 4.5 20–30 45 1.7 240 9.0

2.0–4.9 100 3.75

5–10 80 3.0

>10 60 2.2

Beet <2 120 4.5 15–20 20 0.75 120 4.5

2.0–4.9 100 3.75

5–10 80 3.0

>10 60 2.2

Radish <2 60 2.2 1.5–2.5 10 0.4 20 0.75

2.0–4.9 40 1.5

5.0–10 20 0.75

>10 10 0.4

Parsnip * 86 3.2 10 31 1.2 48 1.8

Turnip, <2 120 4.5 15–20 20 0.75 120 4.5

rutabaga 2.0–4.9 100 3.75

5.0–10 80 3.0

>10 60 2.2

aAmounts are for optimum soil test levels. Apply 50% of the given rate if the soil test is high and omit if the soil test is excessively high.If soil test is low or very low, increase rates according to the soil test recommendations.

*Nitrogen recommendation for parsnips is based on average soil organic matter.

10Harvest, handling, and storageHarvest root crops when they are sweet and sizeablebut not too large or fully mature. Harvest root cropsall at once with a tractor-pulled digger-lifter or byhand after loosening the soil with a fork. Crops soldwithout their tops are usually topped by machine dur-ing harvest, while bunched crops are pulled by handafter they are dug by machine. Make bunches ofradishes, beets, or turnips in the field by wearing asupply of rubber bands on one wrist and forming thebunch with the other hand as you go.

Root crops can be washed clean in a rotating barreltype of washer, or with a strong spray of waterdirected at produce placed on screen tables, orsoaked in a water bath. After washing, allow rootcrops to dry on screen tables and pack them intowaxed cardboard boxes. It is very important to main-tain high humidity to prevent shriveling. Line boxeswith a damp cloth, or pack produce in perforatedplastic bags. Store root crops in a cooler at 32°F and95% relative humidity.

CarrotsFresh market carrots are often sold as bunch carrotswith their tops, and are harvested by undercuttingthe roots and then pulling and bunching them byhand. Carrots are usually ready to harvest 60–70days after planting. Immature, bunched carrots willkeep for 2 weeks in a cooler. Carrots planted for stor-age are ready approximately 100 days after planting,just before the ground freezes. Remove their tops. Ina cooler at high relative humidity, storage carrots willkeep 7 months.

ParsnipsHarvest parsnips after a light frost. Low temperatures(32°F) make parsnips sweeter by causing rootstarches to convert to sugars. The longer parsnipsare stored, the more starch in the root is converted tosugar and the sweeter they taste. Parsnips can bestored in a cooler or in the field over winter if a thickmulch is used to prevent the ground from freezing.

BeetsHarvest beets when roots are still round and tender,usually 50–60 days after planting. Beets are typicallysold in bunches and will keep in top quality in acooler for 10–14 days. Mature, topped beets for stor-age will keep 6 months in a cooler.

Harvesting&packing tips

When you harvest root crops, change yourposition often to minimize stress and fatigue toyour body. Use garden carts and wagons asmuch as possible to minimize lifting and handcarrying heavy produce. Standardized ventedplastic containers that stack are easy to loadand unload, and clean.

With a smooth level floor in the packing area, apalletized packing and storage system can bedesigned to fit small-scale operations (smallpallets moved with a hand-pulled pallet-jack) orlarge operations (pallets moved by forklift).Heavy boxes of produce can be moved fromone area to another on roller tables.

Layout your washing and packing area to mini-mize stooping, lifting, and carrying. Set up bar-rel washers, screen tables or water baths attable height. Ideally, tables could be adjustedto match each worker, so that work is per-formed at a height between wrist and elbow.

11RadishesHarvest spring radishes 20–25 days after seeding assoon as they reach marketable size. Radishesquickly turn pithy if left too long in the field.Hydrocool radishes by submerging them in coolwater for a few minutes to remove field heat.Bunched radishes keep 1–2 weeks in a cooler andtopped radishes keep 3–4 weeks. Winter radishesare ready 50–60 days after planting. Daikons are brit-tle and easily break during harvest. They are usuallysold with 2 inches of leaves left on, and will keep in acooler for 6–10 weeks.

RutabagasRutabagas are ready to harvest 100–110 days afterplanting, and they become sweeter after frost. Theyshould be 3–5 inches in diameter and trimmed of allbut 1–2 inches of leaves. Rutabagas keep in a coolerfor 6 months.

TurnipsTurnips are ready either when young, small, andsmooth at 30 days after planting, or full size at 40–50days, although they’re sweeter 60–70 days afterplanting. They can be 11⁄2–3 inches in diameter. Theyare sold either with or without greens. With greens,turnips keep in a cooler for 10–14 days. Mature,topped turnips keep up to 6 months.

Insect management

Aster leafhopperDescription: The aster leafhopper isa serious pest of carrots because ittransmits the aster yellows phyto-plasma (discussed in disease sec-tion). Adult aster leafhoppers are olive-green, wedge-shaped, and about 1⁄5inch long. Adults have six spots onthe back of the head. Nymphs are

similar in shape to the adults, but are cream coloredand lack fully developed wings. Adults are extremelyactive and jump, crawl, or fly when disturbed.Nymphs are less active but crawl rapidly.

Life cycle: The first leafhoppers that appear eachseason migrate from the Gulf states. Each year theythey are carried in on warm, southerly winds. Largeinfluxes may occur in June and early July as localpopulations develop. Adult females lay eggs in theleaves of susceptible plants. Nymphs hatch 5–7 dayslater and mature in 20–30 days. There are normallytwo to five generations per year.

Damage/Symptoms: Both nymphs and adults feed byinserting piercing-sucking mouthparts into the plantto extract sap. If a leafhopper feeds on an infectedplant, it ingests the aster yellows pathogen. When theleafhopper moves to another plant to feed, it trans-mits the pathogen in its saliva. In carrots, diseasesymptoms appear about 3 weeks later. Symptomsmay appear as early as 10 days after infection or aslate as 40 days after infection.

Management: Aster leafhoppers may be effectivelycontrolled by excluding them from the carrot plantingwith floating row covers. Row covers should be inplace from the time the carrots emerge until 30 daysbefore harvest. Drape the covers over the crop orsupport it using wire hoops. Hold the material inplace by burying the edges or by weights such asreebar. Completely seal all four edges to the ground.

If you’re not using row covers, the only effective wayto prevent the spread of aster yellows disease isthrough insecticidal control of aster leafhoppers. Tocontrol leafhoppers, you need to know both the sizeof the population and the percent of the populationthat’s infective. Place yellow sticky cards in the field

harvest Rinsect m

anagem

ent

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

other insects, helping to keep popula-tions in check. You can take

advantage of this free naturalresource by minimizing the useof broad-spectrum insecticides.

For more information about biologi-cal controls, see Extension publication

Biological Control of Insects and Mites: AnIntroduction to Beneficial Natural Enemies

and Their Use in Pest Management (NCR481).

12early in the spring when plants are newly sprouted.Place the cards just above the crop a few rows infrom the outer field edge. Begin scouting weeklywhen you find leafhoppers on the cards. Use a sweepnet to take 25 sweeps per site, and sample two sitesper acre. Each spring, the University of Wisconsin-Extension collects samples of migrating leafhoppersand determines the percentage that are infective. Forcurrent information, contact your county Extensionoffice. If the percent of infectivity is not known, use2.5% for the following calculations. To decide whethertreatment is necessary, multiply the number ofleafhoppers per 100 sweeps by the percent infectivityof the migrant populations. Treat resistant carrot culti-vars when an index of 100 is reached, intermediatecarrots at an index of 75, and susceptible cultivarswhen the index is 50. Because it takes a month for thesymptoms of aster yellows to develop, treatment maybe discontinued 30 days before harvest.

Remove weeds from field edges as these may be areservoir for the pathogen. Avoid planting suscepti-ble crops near untreated crops or weeds that theleafhopper uses for refuge. If not using insecticidesor row covers, consider planting an additional 30% tooffset losses due to aster yellows.

Flea beetlesDescription: Flea beetles are occa-sional pests of beets, radishes, andturnips in the Midwest, especially infields that are weedy or surroundedby weeds. The larvae are delicateand threadlike with white bodies andbrown head capsules. Flea beetleshave characteristically large hind

legs, which makes them excellent jumpers. Theadults are 1⁄12–1⁄10 inch long.

Life cycle: Flea beetles overwinter as adults in leaf lit-ter, hedgerows, windbreaks, and wooded areas. Thebeetles become active when temperatures reach50°F and emerge in late April, feeding on weeds andvolunteer plants until the new crop emerges. Adultsbegin laying eggs in the soil at the base of hostplants in May. Eggs hatch in 7–14 days and larvaefeed on various plant parts until full grown. The lar-vae pupate in earthen cells for 11–13 days beforeemerging as adults. There are two generations peryear in Wisconsin.

Damage/Symptoms: Adult flea beetles chew tiny circu-lar holes or pits in the leaf tissue. On seedlings, heavyinfestations may cause plant stunting or death. Largepopulations usually do not cause economic damageon older plants. Larvae of most species feed on rootsbut generally cause little damage. Larvae of thehorseradish flea beetle will also mine in the stem andleaf veins. Many flea beetles are vectors of virusesand some bacteria.

Management: Early plantings may avoid high popula-tions of flea beetles while the plants are small andvulnerable. Enclosing seed beds with floating rowcovers will protect plants from egg-laying adults.Removing alternate weed hosts, deep plowing ofcrop residue in the spring, and crop rotation will helpcheck flea beetle populations.

Scout for adult flea beetles using a sweep net. Take25 sweeps per site, sampling at least one site peracre. Because flea beetles can move into a fieldquickly, scout newly planted fields every 1–2 days.Treat with insecticides only when flea beetles are sonumerous on small plants that feeding is causingstand reductions.

AphidsDescription: Numerous species ofaphids feed on vegetables. Thecabbage aphid and the turnipaphid are two of the more com-mon species found in radishes,turnips, and rutabagas. Adultaphids are pear-shaped insectsabout 1⁄10 inch long.

The common wingless form of the cabbage aphidhas heavy surface wax that gives it a dull greencolor; the wingless form of the turnip aphid is lightergreen. Winged forms of the turnip aphid are palegreen with black body markings and a black head.

Life cycle: Cabbage and turnip aphids overwinter aseggs on plant debris. Each female aphid typicallyproduces 80–100 young aphids. When foodbecomes scarce, winged females are produced sothey can colonize other sites. Aphids breed through-out the season.

13Damage/Symptoms: Feeding damage from heavyinfestations causes leaves to curl or wilt. Aphids, par-ticularly cabbage aphids, can transmit viruses duringfeeding.

Management: Insecticidal soaps are very effective incontrolling aphids. The soap must come into contactwith the aphids to provide control. A spreader-stickeris often necessary to get thorough and even cover-age of the soap on the plant. Several parasitic waspsnaturally control both species of aphid. Diaeretiellarapae is a small parasitic wasp that controls the cab-bage aphid and is available commercially. Reflectivemulches have been shown to repel aphids by caus-ing confusion when the winged forms are looking fora place to land. Typically, aphids look for dark areaswhich are present in clean cultivated fields. By usinga reflective material as a mulch between rows, theaphids become disoriented when seeking a landingsite.

CutwormsDescription:Cutworms arethe larvae ofnocturnal greymoths. Theytend to feed ator just below

the ground surface at night. Cutworms are activefeeders on young foliage and stems and will cut offmany young seedlings in an evening. The large(11⁄2–2 inches), fleshy larvae curl up into a tightC-shape when disturbed.

Life cycle: Few cutworms overwinter in Wisconsin.Beginning in late May, moths migrate into the state.Female moths lay hundreds of eggs either singly orin clusters. Most eggs are laid on low-growing,grassy vegetation or plant residue from the previousyear’s crop. Once the eggs hatch, the young larvaefeed above ground on the tips of plants. Larger lar-vae feed at or just below the soil surface at night oron cloudy days. During the day they hide in the soilor beneath foliage. There are three to four genera-tions per year in Wisconsin, but the first generation isthe most damaging because it coincides withseedling plants.

Damage/Symptoms: One large larva may destroy sev-eral plants in one evening. The larvae often pull thestem of the severed plant into their subterranean bur-rows.

Management: Since female moths prefer to lay eggsin grassy areas, controlling grassy weeds lessens thepossibility of problems. Avoid planting in low, wetareas or in areas where grassy plants or weedsexisted the previous year. Insecticides may be usedin areas where cutworms historically have been aproblem. Fields should be scouted if feeding dam-age is observed. Shake every plant along a 5-footlength of row in two adjacent rows into the furrow andcount the larvae on the soil surface. Spot treat if youfind two or more larvae per foot of row.

Root maggotsDescription: The cab-bage maggot and seedcorn maggot both posepotential problems in root

crop plantings. The adults of both insects are flies,similar in appearance to the common housefly. Themaggots are approximately 1⁄4-inch long, white tocream-colored, and legless with a sharply pointedhead end.

Life cycle: Root maggots pass the winter as pupae inthe soil. In early to mid-May, adults emerge from thesoil and lay eggs on the soil surface within 1–3inches of the plants. As the eggs hatch, the larvaebegin feeding on and in the roots. There are three tofive generations per year.

Damage/Symptoms: Seed corn and cabbage mag-gots feeding damages the root leaving brown tun-nels. It may also introduce disease organisms thatmay kill the plant or make it unmarketable. Maggotscan be especially damaging to seedlings, injuringthe growing point of the root. Affected plants areoften stunted and off-color. Seed corn maggots feedon ungerminated seeds as well as roots.

Management: Rutabagas are especially susceptibleto root maggot damage and require stringent maggotcontrol in southern Wisconsin. Insecticides applied atplanting time are recommended in areas that rou-tinely suffer cabbage maggot damage.

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14Prevention is the best method of root maggot control.Late plantings (mid-June) are generally damagedless than early plantings. To avoid heavy infestations,do not plant root crops during peak fly emergence.You can predict peak fly emergence by monitoringdegree day accumulations (for a discussion ofdegree days, see sidebar). Begin degree day calcu-lations once the ground thaws.

For cabbage maggots, use 43°F as the base temper-ature in your calculations. Use 39°F for seed cornmaggots. The first generation of adult cabbage mag-gots peaks at 300 DD43. Seed corn maggots peak at200 DD39.

An alternative method for monitoring emergence is toplace three or four yellow plastic dishpans filled withsoapy water along the field edge at 100 ft intervals inearly April. Check traps every 4–6 days. Remove andcount any flies and add fresh soapy water. Keeprecords of the number of flies trapped to determinewhen fly numbers are building up or tapering off.Floating row covers may be used to protect suscepti-ble root crops during flights of adult seed corn andcabbage maggots.

Temperature affects the rateof development of plantsand insects. Cold weatherslows development whilewarm weather accelerates it.For this reason it is mislead-ing to describe developmentin terms of time alone. Tomonitor crop developmentand predict pest behavior,professional pest managersoften use a system thattakes into account the accu-mulation of heat with pass-ing time. This system isbased on degree days (DD).

A degree day is a unit ofmeasure that occurs foreach degree above a basetemperature during a 24-hour period. The base tem-perature is the temperature

below which there is noplant or insect development.Specific insects have spe-cific base temperatures.Most plants use a base tem-perature of 50°F. Cool-sea-son plants, which includesmost root crops, grow incooler temperatures andhave a base temperature of40°F. Begin recordingdegree day accumulationsfor Wisconsin on March 1.

To monitor plant and insectdevelopment using degreedays, you will need a maxi-mum/minimum thermometerto obtain the daily high andlow temperatures. Calculatedegree days using theequations below.

Example: Assume you haveaccumulated 200 degreedays to date using a basetemperature of 40°F. If yes-terday’s high temperaturewas 75°F and the low was60°F, then the daily averagetemperature would be67.5°F [(75 + 60) ÷ 2]. Tocalculate the degree dayaccumulation, subtract thedaily average from the basetemperature for a total of27.5DD (67.5 – 40). Add thisnumber to the total numberof degree days to date(27.5 + 200) for a new totalof 227.5.

(daily higha + daily lowb) ÷ 2 = daily average temperaturedaily average temperature – base temperature = degree day accumulationaUse 86°F if the high temperature for the day is more than 86°F.bIf the daily low is less than the base temperature, use the base temperature.

Calculating degree days

Disease management

Aster yellowsHosts and severity: Aster yellows is a potentially seri-ous disease of carrots, parsnips, and radishes aswell as many other vegetables and ornamental flow-ers. The disease is caused by a phytoplasma organ-ism which is similar to a virus.

Disease cycle: The phytoplasma that causes asteryellows is transmitted by at least 17 species ofleafhoppers. The pathogen overwinters in the bodiesof adult leafhoppers or in perennial host plants suchas weeds and ornamentals. Nymphs and adultleafhoppers acquire the pathogen through feedingon infected plants. Once inside the leafhopper, thephytoplasma mutiplies. An incubation period of atleast 10 days must pass before the leafhopper cantransmit the pathogen back to plants. The insect mayremain infective for at least 100 days. Plants first showsymptoms 10–40 days after they become infected.

Symptoms: The first symptom on carrots is yellowingand vein clearing of young leaves at the center of thecrown. Next, dormant buds break and grow intochlorotic shoots. This gives the plant a short bunchyor witch’s broom appearance. Old leaves becometwisted and reddened or bronzed. They eventuallybreak off, leaving a top that consists only of shortadventitious shoots. These plants are difficult to har-vest mechanically and bunch for market. Roots ofinfected plants are usually malformed and havenumerous hairy secondary roots arising from them.The roots tend to be stunted, woody or tough, off-fla-vor, and have poor color. The crowns of diseasedplants are predisposed to soft-rot bacteria in moistweather. Infected carrots grown for seed propagationoften die before the seed is mature.

Management: There is no cure for aster yellows, socontrol is aimed at disease prevention. Controlleafhoppers or exclude them from susceptible cropsusing floating row covers. Planting tolerant cultivarsof carrots, parsnips, and radishes will reduce the losscaused by the disease in years of severe outbreaks.Also, remove weeds from field edges that may serveas a reservoir for the pathogen.

Alternaria leaf blightHosts and severity: Alternaria blight is a commonfoliage disease of carrots. In warm, moist weather,leaf spots develop so rapidly the entire field mayappear to have been injured by frost or chemicals.The disease is seldom serious until plants approachmaturity. Petioles of leaves weakened by Alternariablight become brittle and often break off during har-vest, resulting in unharvestable carrots.

Disease cycle: The fungus that causes Alternariablight overwinters in diseased debris in the soil. Itmay also be spread on or in contaminated seed.During the growing season, spores are disseminatedby wind, water, splashing rain, and field equipment.Infection takes place rather slowly unless a favorableenvironment is present. The fungus survives up to 2years in the soil.

Symptoms: Initially, small, dark brown to black spotsappear on leaves. The edges of leaflets turn chloroticyellowish-green. As the irregularly shaped lesionsincrease in size and number, the entire leaflet shrivelsand dies. The dead foliage has a burnt appearance.Large elongated lesions may form on the petiole,girdling and killing the entire leaf before any spotsdevelop. Alternaria also causes damping off ofseedlings, blights of seed stalks, and a black decayof the roots. Initially, the disease occurs irregularly, insmall patches within a field. Later, Alternaria blightbecomes fairly uniform throughout the field.

Management: Randomly collect 50leaves from the field. If 25% of theleaves sampled are infected,approximately 1–2% of the cropis infected and fungicide treat-ment should be initiated.

Plants that exhibit nitrogen defi-ciency are most susceptible to thisdisease. To control Alternaria blight,practice a 3-year crop rotation andspray the foliage with a protectant fungi-cide. Fall plowing after harvest is recom-mended in infested fields to hastendecomposition of infected debris. Selectwell-drained sites when planting new fields.

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Cercospora blightHosts and severity: Cercospora blight is anotherimportant foliage disease of carrots. It can also infectbeets. Cercospora does not infect the edible carrotroot. It is severe on young leaves and developsrapidly when plants are relatively young.

Disease cycle: The fungus overwinters on infectedplant debris and wild hosts such as Queen Anne’slace. Spores are produced on this debris and arecarried by wind or water to young carrots. The fun-gus enters the plant through pores in the leaf (stom-ata). Lesions appear after 3–5 days and new sporesare produced soon thereafter.

Symptoms: The symptoms of Cercospora blightresemble those of Alternaria leaf blight but are moresevere on the younger leaves and develops rapidlywhen plants are young. Conversely, Alternaria blightis more severe on older plants. Although lesionsdevelop on the leaves and later cause leaf curling,Cercospora may attack any aboveground part of theplant. It does not affect the fleshy root. Leaf lesionsare circular with dead centers and diffuse chloroticborders. Lesions at the margins of leaves are some-what elongated. The spots expand until the wholeleaflet dies. During humid weather, the lower surfaceof the lesion turns light gray with spore masses. Thefungus may also produce quantities of spores on thepetiole, where tan, elliptical lesions develop.Eventually the petiole may be girdled and the leafkilled. Cercospora blight occurs in July and August.

Management: Fall plowing to hasten decompositionof infected debris coupled with a 2- to 3-year croprotation will aid in the control of Cercospora blight.Protective fungicides are often necessary.

Black rotHosts and severity: Black rot is a bacterial diseasecommon to plants in the cole crop family includingturnips, rutabagas, and radishes. In Wisconsin, blackrot is typically not serious on these crops. It iscaused by the bacteria Xanthomonas campestris pv.campestris.

Disease cycle: The bacteria overwinters in diseasedplant debris and in seed. Plants can be infected bythe black rot bacteria at any stage of development.The bacteria survives 1–2 years on plant debris, butis often harbored in cruciferous weeds that act as areservoir.

Symptoms: The first signs of the disease appear atthe leaf tip where initial infection most often occurs.The tissue of the infected leaf turns yellow, usually ina V-shaped area with the base of the V toward themidrib. The symptomatic area soon dies and becomestan and dry as the disease progresses. In the yel-lowed tissue, the veins become dark. Holding the leafup to a bright light reveals a network of black veins.Infected roots are dark and break down internally.

Management: It is best not to save seed from turnips,radishes, or rutabagas as the disease is readilyseedborne and can infect the next year’s crop. Toprevent problems with black rot, plant only disease-free seed. Seed grown in the western United Statesis recommended. Rotating fields out of crucifers forat least 3 years will reduce the likelihood of pathogenbuild-up in the soil. Never cultivate or move irrigationequipment while the foliage is wet as this may helpspread the disease. Do not compost infected debris.To hasten decomposition, plow debris under immedi-ately after harvest.

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ClubrootHosts and severity: Clubroot is a serious disease ofcole crops. The fungus, Plasmodiophora brassicae,infects the below-ground parts of radishes, turnips,and rutabagas. Although the direct effects of club-root may not always be economically important, oncethe soil becomes infested, it remains so for an indefi-nite period, even in the absence of susceptiblehosts.

Disease cycle: The organism that causes clubrootcan remain in the soil for 10 years or longer. Infectionoccurs through root hairs and wounds. As the rootenlarges and spores of the fungus are produced, soilbecomes contaminated. Infested soil is disseminatedby equipment, human activity, and running water.

Symptoms: The most noticeable symptom of clubrootis the abnormal enlargement of the roots. Theseenlargements may occur on the very small roots,secondary roots, taproot, or underground stems. Theroot clubs are often thickest at the center, taperingtoward either end. Plants with clubbed roots arestunted and leaves may yellow or wilt. In root cropswhich normally have fleshy roots, infection usuallyonly occurs on the smallest secondary roots and theedible taproots are not affected.

Management: The best method of managing clubrootis to avoid infection in the first place. Plant cruciferson well-drained soils and use clean transplants.Practice long crop rotations of at least 7 years andremember that turnips, radishes, and rutabagas arein the same plant family as cabbage, broccoli, cauli-flower, and other cole crops when planning a croprotation. Maintain a soil pH of at least 7.2. Radish cul-tivars such as Galahad, Red King, and Red Pak areresistant to clubroot and may be used where the dis-ease has been a problem in the past. However, thereare several strains of the fungus that causes clubrootand cultivars may be resistant to one strain but sus-ceptible to another.

Downy mildewHosts and severity: Downy mildew is a cool-weatherproblem that affects cole crops including turnips,radishes, and rutabagas. There are several strains ofthe fungus, each strain causing infection only on aspecific crop with no cross infection occurring.

Disease cycle: The fungus overwinters as thick-walled resting spores in diseased plant residue. Inthe spring, the overwintering spores germinate andinfect susceptible hosts. Heavy fogs, persistentdews, and drizzling rains favor infection. Plants maybe infected at any stage of development.

Symptoms: Symptoms of downy mildew first appearas small, purplish or yellow-brown spots on theleaves. Young leaves may turn yellow and drop whileolder leaves become tan and leathery. In severecases, the entire leaf dies. Turnip and radish rootsbecome discolored from the root crown downward.The flesh may be brown or black and may be discol-ored in a net-like pattern. In advanced stages, theskin becomes roughened by tiny cracks or the rootmay split open.

Management: Downy mildew can be seedborne so itis important to purchase only certified disease-freeseed. Do not save seed from plants. To reduce thelikelihood of infection, practice a 3-year crop rotationout of crucifers and control cruciferous weeds, par-ticularly mustard weeds.

Black rootHosts and severity: Black root is caused by the soil-borne fungus Aphanomyces raphani. This diseasecan be economically important in radish, turnip, andrutabaga production.

Disease cycle: The fungus overwinters as thick-walled resting spores in diseased plant residue. Inthe spring, the overwintering spores germinate andinfect susceptible hosts. The fungus enters the rootwhere the side roots emerge from the taproot orhypocotyl. Plants may be infected anytime. The fun-gus survives in the soil for at least 1 year.

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Symptoms: Infected areas of the root turn bluish-blackand discoloration radiates inward. These areasenlarge in size until the root is girdled. Shortly afterthe root is girdled, the aboveground part of the plantwilts and dies.

Management: Because the fungus overwinters in thesoil, crop rotations of at least 4 years out of crucifersis recommended. White varieties of radish are mostsusceptible and should not be planted in infestedsoil. The radish varieties Fancy Red II, Fuego, andVintage are resistant to black root.

Turnip anthracnoseHosts and severity: Turnip anthracnose may besevere on turnips, radishes, and rutabagas.

Disease cycle: The fungus overwinters on infectedplant debris and weed hosts. Warm, moist conditionswith temperatures of 80°–86°F favor infection.

Symptoms: The fungus primarily causes a small, drylesion to develop on the leaves. On infected roots,small, tan or gray sunken areas develop. Theselesions provide a point of entry for bacterial soft rotwhich can destroy the edible portion of the roots.

Management: Purchase certified disease-free seed.Prompt incorporation of diseased plant residues atthe end of the season will hasten decomposition andlong crop rotations of at least 4 years are recom-mended to reduce the amount of inoculum in the soil.

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.

Non-chemical weed control in root crops is often diffi-cult because of the relatively small canopy producedby these crops as compared with bean, tomatoes, orvine crops. Repeated cultivations are often neces-sary to reduce weed competition in root crop planti-ngs. Sometimes hand cultivation or hand weeding isnecessary.

Chemical weed control in carrots is based on thetype of soil on which the crop is grown—muck vs.mineral soil—because the species of key weeds willdiffer as will the selection of available herbicides.

Cultivate beets up to three times during the season.You can clip weeds which grow above the top of thebeet foliage. Before planting beets you can apply agrass herbicide and incorporate it into the seedbed.After planting but before beets emerge, you canapply a broadleaf herbicide.

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Additional reading

CultureDirect 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.

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.

Producing Vegetable Crops. Fourth Edition. John M.Swiader, George W. Ware, and J.P. McCollum. 1992.Interstate Publishing.

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 © 1998 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, Collegeof Agricultural and 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 department of Biological Systems Engineering, College of Agricultural and LifeSciences, University of Wisconsin-Madison. Produced by Cooperative Extension Publishing, University ofWisconsin-Extension.

University of Wisconsin-Extension, Cooperative Extension, in cooperation with the U.S. Department of Agriculture andWisconsin counties, publishes this information to further the purpose of the May 8 and June 30, 1914 Acts ofCongress; and provides equal opportunities and affirmative action in employment and programming. If youneed this material in an alternative format, contact the Office of Equal Opportunity and Diversity Programs orcall Cooperative Extension Publishing at 608-262-8076.

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

A3686 Growing Carrots, Beets, Radishes, and Other Root Crops in Wisconsin:A Guide for Fresh-Market Growers I-1-98-1.5M-500

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