Beta vulgaris (Chenopodiaceae)
Colorado Facts
| 1997 | 1998 | 1999 | 2000 | 2001 | |
| Acres in Colorado: | 66,400 | 57,300 | 68,500 | 53,600 | 36,800 |
| Percent U.S. Acreage: | 4.5% | 4.2% | 4.6% | 4.6% | 3% |
| National Ranking | 6th | 7th | 7th | 7th | 9th |
| Per Acre Value (Net): | $626.19 | $803.58 | $668.82 | $645.75 | n/a |
| Value of Production in Colorado: | $42,518,000 | $46,055,000 | $45,813,000 | $34,612,000 | n/a |
Number of Growers in 1997: 600
Data from 1997-2001 Colorado and National Agricultural Statistics Services
Description of Crop
Sugarbeets are a biennial, warm season crop. It is grown as an annual crop and not taken into the second year of production unless it is being grown for seed. The taproot grows about 8" deep and is harvested for sucrose. Sugarbeets are known for their abundant foliage; sugar content is proportional to the size and development of the leaf surface. Weld County is ranked #1 in the state with 26,700 acres of sugarbeets.Cropping System
Sugarbeets should be planted in March or early April, allowing 150 - 160 days between planting and harvesting. Recommendations are around April 15 for rapid germination. Earlier planting (when soil temperatures are cooler) reduces the risk of loss due to rhizomania. Favorable planting temperatures are between 40 and 60 F. There is a risk of freezing if seeds are planted too early in the season; replanting may be necessary. Optimal soil pH is between 6 - 8. Sugarbeets should be planted at a depth of 0.75 - 1.25". Narrow row widths (usually 30", although some growers use 22" row widths) help plants compete better with weeds. Fifty-five thousand uniformly placed sugarbeet seeds per acre is average. Sugarbeets are planted in beds 6" apart.
A crop rotational system where sugarbeets follow barley or wheat is very successful; they also do well with corn, potatoes, or summer fallow. Sugarbeets are not planted with dry beans or soybean, as the nitrogen levels in the soil are too high. Nitrogen management is critical to sugarbeet cropping systems. No manure is applied to sugarbeet fields in the spring.
Sugarbeet plants, especially seedlings, need a drier environment, or insect and disease problems will become more prevalent. Disease development is favored by high soil moisture, so it must be managed to minimize the need to irrigate during the first six weeks after seed germination. However, if the soil is too dry, seedlings can dry out and plants will be blown over by the wind.
All sugarbeets in Colorado are irrigated by either center pivot or furrow irrigation. When furrow irrigating, the beets are watered up to every week, depending on the weather and growing stage of crop.
Harvest begins in October. Adequate soil moisture makes beet removal easier. Cool air temperatures are required for successful storage of sugarbeet tubers.
Sugarbeets can be successfully planted with no-till, strip-tillage or other reduced tillage systems. However, deep tillage, which is used to improve drainage, will help reduce the risk of soil borne diseases (mainly the beet necrotic yellow vein virus causing rhizomania).
Location of Production
Northeast
Adams, Kit Carson, Logan, Morgan, Phillips, Sedgwick, Washington, Weld, Yuma
Northwest
Boulder, Larimer
Note: Shaded boxes indicate counties where the crop is grown. Regions have been delineated by Interstates I-70 and I-25.
Key Insects
Several cutworm species attack a wide range of plants. Most feeding occurs at night. The larvae hide in the soil near the surface during the day. Full grown cutworm larvae are 1.5 - 2" long. Coloration will vary among species, but all tend to be stout-bodied caterpillars with four sets of prolegs. They curl into a ball when disturbed. Seedlings are girdled at the soil line and stands may be significantly reduced in some cases. Life cycles vary among the different species. Several generations may occur each year, but overwintering larvae and the first generation in the spring are the most damaging. Larvae overwinter in the soil, especially in grassy or weedy situations. Fall and spring cultivation will help reduce populations of overwintering larvae. Insecticides such as carbaryl, chlorpyrifos, methomyl, or methyl parathion are effective if applied in a timely manner and directed at the soil around the base of the crop plants.
Sugarbeet Root Maggot, Tetanops myopaeformis
The sugarbeet root maggot is the most severe insect pest of sugarbeets in Colorado. Adult flies are similar in size and appearance to the house fly (about 0.25"). However, the body is shiny black with few hairs. Larvae are white, legless maggots that grow to about 0.25 - 0.33" in length. The head end is tapered to a point and the rear end is blunt. The pupae are tan to brown, elongate capsules about 0.31" long. Sugarbeet root maggots overwinter as full-grown larvae about 10 - 14" deep in the soil. As temperatures rise in the spring, the larvae move close to the soil surface and pupate. Sugarbeet root maggots pupate in April, and flies begin to emerge in early May. The flies move from last year's sugarbeet fields to the current fields soon after emergence. They are not strong fliers, and generally movement is limited to localized flights to adjacent fields. Fly activity in sugarbeet fields is greatly increased under warm and calm conditions. During cool or windy periods the flies remain in sheltered areas along field margins. Peak emergence and fly activity occur in late May or early June. Females lay eggs in the upper 0.25 - 0.5" of soil at the base of the sugarbeet plants. White, elongate eggs are laid in batches of a few to 40. Survival of eggs and early larval stages is greatly reduced in dry soil conditions. Larvae begin to feed on the sugarbeet roots and continue to feed for about 3 - 4 weeks. By late June to early July, feeding ceases, but the larvae remain in the soil around the sugarbeet roots. Root maggots feed on the surface of the sugarbeet root causing surface scarring. Deeper scarring and malformed roots may result from heavier feeding. Heavy infestations of the sugarbeet root maggot can cause severe stand loss, particularly with small plants because the maggots feed on and sever the tap root. Severe damage results in wilted or dead plants. Losses may also result from reduced plant vigor. Damaged plants also may be more susceptible to root diseases.
White Grubs, Phyllophaga spp.
White grubs are U-shaped insects ranging in length from 0.5 - 1.5". These larvae live in the soil for extended periods of 1 - 3 years. Most white grubs have a three-year life cycle. Adults are active in the early summer when they emerge from the soil, mate and lay their eggs in grass or pasture areas. They feed on sugarbeet roots and can cause problems early enough in the season that plant damage can lead to stand loss. Plants damaged at this time wilt and die. Late season feeding can also result in sugarbeets with severely pitted leaf surfaces caused by grub feeding.
Wireworms, Family: Elateridae
Wireworms are the larval stage of a family of beetles commonly called click beetles. Adults are brown or black and elongate, tapering toward each end but more so towards the rear. Earlier larval stages are very small and white, later stages have a characteristic hard shell appearance and a shiny yellow to reddish-brown color with six slender legs. Mature larvae range from 0.5 - 1" in length, depending on the species. Wireworms usually overwinter in the adult stage. Females deposit eggs in the soil. When the eggs hatch, larvae feed on tubers. In potatoes, wireworms usually stay in the top two or three inches of soil. During the winter, they move as far down as 2' deep. Larvae require 2 - 5 years for maturation and most damage is caused by older larvae. Fully developed larvae pupate in the soil. Emergent adults remain in the soil until the following spring. Wireworms feed on seed pieces in the spring, occasionally damaging young shoots. The damaged seed pieces secondarily become infected with bacteria or fungi, and plants grow weakly or fail to emerge. Later in the summer, wireworms bore into tubers, leaving straight round holes that usually heal over and do not become infected with rotting microorganisms. As plants mature, wireworms girdle plant stems. Wireworm cultural controls include rotating to non-host crops and tilling fallowed fields. If stand growth is significantly reduced early in the season, replanting may be an option.
Additional Insects
Flea Beetles: Potato Flea Beetle, Three-spotted Flea Beetle, Pale Striped Flea Beetle and Tuber Flea Beetle, Epitrix cucumeris, Disconycha triangularis, Systena blanda and E. tuberis
Adult beetles are typically small, often shiny, and have large rear legs that allow them to jump like a flea when disturbed. Flea beetles overwinter in the adult stage hidden under leaves, dirt clods, or in other protected sites. They become active during warm days in mid spring but may straggle out over several weeks. Many flea beetles are strong fliers and seek out emerging host plants that they locate by chemical clues the plants produce. Adults feed for several weeks. Soon thereafter, females intersperse feeding with egg laying. They lay eggs in soil cracks around the base of the plants. The minute, worm-like larvae then move to feed on small roots and root hairs. The larval stage is completed in about a month. The insects pupate and emerge from the soil as adults. There may be a second generation during the summer and, with a few species, a third generation. Flea beetles produce a characteristic injury known as "shot-holing" in which the adults chew many small holes or pits in the leaves, making them look as if a fine buckshot has damaged them. Young plants and seedlings are particularly susceptible. Growth may be seriously retarded and plants even killed. Leaf feeding also damages plant appearance, which can impact the marketability of leafy vegetable crops. Although flea beetles are common, injuries are often insignificant to plant health. On established plants, 10 - 20% or more of the leaf area must be destroyed before there is any negative yield effects.
Garden Symphylan, Scutigerella immaculata
Symphylans are fast moving soil arthropods that resemble centipedes. They grow up to 0.375" long, have long antennae and can have up to 12 pair of legs. Their entire life cycle is spent in the soil. They will move up and down in the soil depending on soil moisture and temperature. Symphylans feed on decaying vegetable matter and small root hairs on the plants. Roots can be severely pruned to the point of very few secondary roots. This damage in the field is quite obvious but most often it is confined to localized spots.
Grasshoppers
Grasshoppers follow roughly a 22-year cycle in Colorado, with the last major outbreak occurring in the late 1970s and early 1980s. Grasshoppers vary considerably depending on the species. Grasshopper nymphs have a similar appearance to adults but are smaller in size. Grasshoppers lay eggs in undisturbed areas, usually in late summer and early fall. Small nymphs or "hoppers" hatch the following spring. Winged adults will appear 5 - 6 weeks after hatch. A few Colorado grasshopper species have eggs that hatch in late summer and overwinter as nymphs. Winged adults of these species usually appear early in the following summer, often causing undue alarm about unusually early grasshopper activity. Some of these species are important on rangeland, but none are considered a threat to field crops. The usual pattern of grasshopper damage in field crops is for early development to occur in weedy areas of roadsides, fence rows, irrigation ditches, and other non-crop areas. As these food sources are exhausted or begin to dry down, the grasshoppers leave in search of other food - often an irrigated crop. Here they will first feed in the field margins and subsequently spread throughout the field. Most field crop damage is caused by the differential, red-legged, two-striped, and migratory grasshoppers.
Leafminers, Liriomyza huidobrensis
Leafminers are shiny, black flies, 0.04 - 0.12" in size, with yellow markings. The leafminer overwinters in the soil in the pupal stage. Adult flies will emerge in May and seek out sugarbeets on which to lay their eggs. The adults are gray and smaller and thinner than a house fly. The larvae are white maggots and are always present in the mine inside the leaf. Females puncture the leaf to feed on plant sap and to lay their eggs within the leaf tissue. When the eggs hatch, larvae feed on the area between the upper and lower leaf surfaces. Larval development within the leaf lasts 7 - 10 days. Following this period, the maggots move to the soil and pupate. The pupal period lasts for 2 - 3 weeks, after which the flies emerge to begin a new generation. While the larvae are small, they create narrow, winding tunnels in the leaves that are visible as water-soaked or whitish areas. As the larvae increase in size and in feeding requirements, the feeding area appears as large irregular blotches on the leaves. These large leaf mines will dry up and darken, giving the plant a very ragged appearance. To minimize pest problems, it is advisable to plant sugarbeets away from lettuce, celery and spinach fields, as they are also susceptible. It may also be necessary to allow a fallow period between harvesting an infected crop and planting other, susceptible plants in the same field.
Lygus Bugs, Lygus hesperus, L. elisus and L. lineolaris
Lygus bug is a term given to a group of insects that are related and have similar appearance and life cycle. These insects feed primarily on flowers and developing seed, but can damage sugarbeets leaves. Economic damage from this insect is rare. Lygus bugs are green to brown with black and yellow markings. They are roughly 0.25" long and have a triangular patch on the back between the wings. They overwinter as adults in debris. Feeding from the lygus bug causes yellow discoloration and distorted growth (puckering) at the leaf tip. Extensive feeding results in severe damage to the heart leaves and produces stunted plants. Damage is most severe early in the season while the plants are small.
Sugarbeet Webworm, Alfalfa Webworm and Garden Webworm, Loxostege sticticalis, L. cerealis and Achyra rantalis
Three species of webworms (sugarbeet, alfalfa and garden) can be found on sugarbeets. They are not very common, but when present in large numbers, damage can be severe. Early instar sugarbeet webworms are light colored and feed within webs near the base of the leaves. Later instars are olive green with a dark stripe down the center of the back. On each body segment there are three circular spots on either side of the center stripe. A long hair projects from each of these spots. The alfalfa webworm has similar spots with protruding hairs, but the stripe on the back is broad, covering nearly the entire area between the spots. Both sugarbeet and alfalfa webworms can reach about 1.5" in length. Garden webworms are the least common webworm and is smaller - only reaching a maximum length of 1". Its markings are similar to those of the other webworms. Webworms overwinter as mature larvae or pupae in the soil. Adult moths emerge in May and begin laying eggs on sugarbeets. Eggs are laid singly or in small groups on the underside of the leaves. There are usually two generations of webworms. Larvae of the first generation feed in June and the second generation feeds in late July or August. Webworm larvae feed on the lower surface of the leaves. These early instars are not able to feed completely through the leaves resulting in a pitting on the lower leaf surface. Larval consumption rates in later instars increase dramatically through the leaves. Substantial defoliation can occur in a short time. This increase in defoliation is especially striking because the early instar feeding often goes unnoticed. After heavy infestations, only the midveins remain on the plant. Heavy feeding can result in damage to the growing point.
Sugarbeet Root Aphid, Pemphigus populivenae (betae)
Sugarbeet root aphids are yellowish green and broadly oval in shape. They secrete a white waxy material that gives their colonies a distinctive appearance. Several generations are produced in the root colonies. These winged aphids fly out of the sugarbeet fields and overwinter on narrow-leaved cottonwoods in the mountains. Some root aphids remain in the soil in the fall and overwinter. These aphids are capable of beginning new infestations on sugarbeets or other host weeds the following spring. Root aphids feed on the small secondary roots of sugarbeets. Their feeding interferes with plant growth by inhibiting nutrient and water uptake and transport. Severe infestations show leaf yellowing and wilting and are often limited spots in the field. This severe damage results in yield and quality losses. Varieties resistant to sugarbeet root aphid feeding represent good management tools for this insect.
Key Insect Management Strategies
Cultural Controls
Avoid planting sugarbeets after alfalfa to alleviate flea beetle problems. Tillage reduces grasshopper egg survival.
Rotating fields out of sugarbeet production for 3 - 4 years, accurate timing and application of irrigation water, and timely planting all improve pest management in sugarbeet crops.
Insecticides-
Pesticide: carbaryl (Sevin XLR Plus)
Pesticide: chlorpyrifos (Lorsban 4E)
Pesticide: chlorpyrifos (Lorsban 15G)
Pesticide: malathion (Malathion 57EC)
Pesticide: methomyl (Lannate LV)
Pesticide: methyl parathion (Methyl Parathion)
Pesticide: phorate (Thimet 15G)
Pesticide: phorate (Thimet 20G, Phorate 20G)
Pesticide: terbufos (Counter 15 CR)
Key Weeds
Barnyardgrass, Echinochloa crusgalli
Barnyardgrass, a member of the Grass family, is an annual that prefers wet sites. It is not usually a problem in well-drained cultivated fields but can grow heavily around irrigation pipe leaks and other wet spots in the field. It is a vigorous, warm season annual grass reaching 1 - 5' in height. Many stem bases are reddish to dark purple. Leaf blades are flat, broad, smooth, and without a ligule or auricle at the junction of sheath and blade. Seed are the only source of reproduction. It flourishes in warm conditions.
Black Nightshade, Solanum ptycanthum
Black nightshade, a member of the Nightshade family, is an annual that grows 6 - 24" tall with glabrous, appressed-hairy stems. Black nightshade is a Colorado noxious weed and varies greatly in form and color. Seed leaves of black nightshade are elongate-oval and pointed; the first true leaves are spade-shaped with smooth edges. Lower leaf surfaces are often purple. Berries turn from green to black when mature and the calyx covers only a small part of the fruit surface. Petioles, stems and leaves have some hairs but are not densely hairy or sticky. Leaves are ovate, smooth to wavy-edged and have a tapered tip. Flowers are white to pale blue, 0.25 - 0.4" wide borne in clusters. Flowering season is from May to October. Seed are the only source of reproduction.
Canada Thistle, Cirsium arvense
Canada thistle, a member of the Sunflower family, was introduced from Europe. It is a creeping perennial which reproduces by seed and fleshy, horizontal roots. Canada thistle is on the Colorado noxious weed list as well as marked as one of the top ten most widespread weeds causing the greatest economic impact to the State of Colorado. Stems are erect, hollow, smooth and slightly hairy, 1 - 5' tall, simple, and branched at the top. The leaves are set close on the stem, slightly clasping, and dark green. Leaf shape varies widely from oblong to lance-shaped. There are numerous sharp spines on the outer edges of the leaves, branches and main stem. The flowers are small and compact, about 0.75" or less in diameter, and light pink to rose-purple in color, occasionally white. The seed are oblong, flattened, dark brown, and approximately 0.125" long. Canada thistle emerges in April or May in most parts of Colorado. Infestations are found in cultivated fields, riparian areas, pastures, rangeland, forests, lawns, gardens, roadsides, and waste areas. Because of its seeding habits, vigorous growth, and extensive underground root system, control or eradication is difficult. It is distributed across Colorado in elevations ranging from 4,000 - 9,500'.
Common Lambsquarters, Chenopodium album
Common lambsquarters, a member of the Goosefoot family, was introduced from Europe. It reproduces by seed. The stem is erect, stout, smooth, grooved, often striped with pink or purple, branched and grows 1 - 6' high. Lower leaves are alternate and ovate. Upper leaves are also alternate, but are more narrow. The flowers are small, green, and crowded in the axils and at the tips of the stems and branches. Common lambsquarters is a succulent, fast growing plant which rapidly removes moisture from the soil.
Field Bindweed, Convolvulus arvensis
Field bindweed, a member of the Morningglory family, is a creeping perennial introduced from Europe. It reproduces by seed and horizontal roots. Field bindweed is on the Colorado noxious weed list as well as marked as one of the top ten most widespread weeds causing the greatest economic impact to the State of Colorado. The stems are smooth, slender, slightly angled, 1 - 4' long and spread thickly over the ground or wind around erect plants and other objects. Leaves are alternate, 1 - 2" long, with great variation in shape. They are somewhat arrow-shaped with spreading, pointed, or blunt lobes at the base. Flowers are bell- or trumpet-shaped, white, pink, or variegated, and about 0.75 - 1" in diameter. Flowering is from June to September. Field bindweed is one of the most competitive perennial weeds. A two or three year food supply is stored in the extensive underground root system. This makes it difficult to kill by cultivation because roots will live as long as their food reserve lasts. Seed remain viable in the soil for up to 40 years. Field bindweed is widespread in cultivated and uncultivated areas including pastures, lawns, gardens, roadsides, and waste areas throughout Colorado from 4,000 - 8,000' in elevation.
Green Foxtail, Setaria viridis
Green foxtail, a member of the Grass family, is generally shorter than other foxtails. Green foxtail is on the Coloraod noxious wed list. Other characteristics distinguishing it from other foxtail species include: roughened leaf sheaths, lack of hairs, and smaller seed than other foxtails. Seed are broadly oval, green and found in spike-like panicles that are 1 - 4" long. Green foxtail is native to Eurasia, but common throughout most of North America. Green foxtail is responsible for reductions in yields, increased seed cleaning costs, and expensive control measures. Flowering and seed production are in July, August and September.
Hairy Nightshade, Solanum sarrachoides
Hairy nightshade, a member of the Nightshade family, is an annual. Hairy nightshade is on the Colorado noxious weed list. Leaves have wavy edges, prominent veins and numerous fine, short hairs, especially along the underside of the main vein. Berries are green or yellowish brown when mature, never black. The calyx covers the entire upper surface of the fruit. The pedicels, like stems and leaves, are usually hairy. Mature plants reach about 2' in height.
Kochia, Kochia scoparia
Kochia, a member of the Goosefoot family, is native of Eurasia. It is an annual, reproducing solely by seed. Kochia is on the Colorado noxious weed list. Flowering season is from July to October. Stems are erect, round, slender, pale green, branched, and 1 - 6' tall. Leaves are narrow, bright green, hairy, numerous and are attached directly to the stem. Upper leaves are more narrow than lower leaves. Flowers are inconspicuous in the upper leaf axils. Seed are about 0.063" long, wedge-shaped, dull brown, and slightly ribbed. Kochia can be found throughout Colorado up to 8,500' in elevation. It has become a major problem on roadsides, waste areas, and non-cultivated fields. In the fall, plants become red, later turning brown and breaking away from the root, causing them to tumble over the ground scattering large amounts of seed. Many kochia populations in Colorado are resistant to sulfonylurea, imidazilinone, triazine and benzoic acid herbicides, representing three very different modes of action. Therefore, care should be taken when using herbicides to control kochia. Some alternative herbicides include: fluroxypyr, bromoxynil, MCPA ester, isoxaflutole, pyridate, flufenacet, fomesafen, glyphosate, lactofen and clomazone. It is important to rotate herbicide modes of action to prevent future cases of herbicide resistance.
Pigweeds, Amaranthus spp.
Pigweeds, members of the Amaranth family, are weed pests in several cropping systems. A. hybridus, smooth pigweed, was the first triazine resistant plant documented. A. retroflexus, redroot pigweed is probably Colorado's most common species. A. lividus, is a prostrate species with a notch in the tip of the leaf. A. spinosus, spiny amaranth, has sharp, stron spines on the stem. A. graecizans, breaks off at the ground line and being round shaped is blown around by the wind. Redroot pigweed is ALS herbicide resistant.
Russian Thistle, Salsola iberica and S. collina
Russian thistle, a member of the Goosefoot family, was introduced from Russia. It is an annual and reproduces by seed. It is on the Colorado noxious weed list. It is a round, bushy, branched plant growing 1 - 3.5' high. The branches are slender, succulent when young, and woody when mature. The first leaves to develop are alternate, dark green, soft, slender, and 1 - 2.5" long. These senesce early and new leaves form which are alternate, short, stiff, spiny, and not over 0.5" long, with two sharp-pointed bracts at the base. The flowers are small, inconspicuous, green-white or pink, and are usually solitary in the leaf axils. Seed are conical and 0.063" in diameter. Russian thistle grows in dry plains, cultivated fields, roadsides, and waste areas, primarily in grain-growing areas of the state. At maturity, the plant breaks off at the base. Its round shape allows it to tumble, scattering seed for long distances. It is widespread over Colorado in elevations up to 8,500'.
Sunflower, Helianthus annuus
Sunflower, a member of the Sunflower family, is a native weed. It is an annual, 1 - 10' tall. Stems are erect, simple to branched and rough. Leaves are alternate, simple, rough, and hairy. Ray flowers are yellow to orange-yellow and disk flowers are brown. Flowering is from July to September. Seed are the only source of reproduction.
Toothed Spurge, Euphorbia dentata
Toothed spurge, a member of the Spurge family, is native to the Great Plains region. It spreads by seed and grows under a wide range of environmental conditions. Toothed spurge is an annual, growing up to 3' tall. Leaves are up to 3" long, ovate to linear, coarsely toothed, mostly opposite, hairy and often dotted with a few purplish-red spots. Stems are many branched and generally curve upwards. Both stems and leaves exude a milky latex when broken. The inconspicuous flowers develop in late summer, followed by 3 sided, turban-shaped, 0.25", smooth, green fruits. Seed are rough, bumpy, oval and gray.
Velvetleaf, Abutilon theophrasti
Velvetleaf, a member of the Mallow family, was introduced from India and is an annual. Velvetleaf is on the Colorado noxious weed list. It is completely covered with soft hairs, has erect stems, is branched, and is 2 - 7' tall. Leaves are alternate, heart shaped, pointed at the apex, are 5" or more in width, and are attached to slender petioles. Flowers are solitary in the leaf axils with 5 yellow petals and numerous fused stamens that form a tube. Flowering and seed production occur from late June to October. Fruits are rounded with 9 -15 arranged in a disk, each containing 3 - 9 egg-shaped, somewhat flattened, rough gray-brown seed. The seed retain viability in soil for more than 50 years, making eradication difficult. Seed are the only source of reproduction.
Additional Weeds
Jimsonweed, a member of the Nightshade family, is a rank-smelling annual. Stems are 0.75 - 5' tall. Leaves are alternate, large, usually unevenly toothed to shallowly lobed. Flowers are trumpet-shaped and 3.5 - 5" long. Jimsonweed has large leaves with spiny capsules that contain several hundred seed. As the capsule matures, it opens at the top and the plant tips it over, allowing all of the seed to fall out. The seed are potent hallucinogens, but are very toxic; several people have become seriously ill or have died from ingesting the seed.
Wild Buckwheat, Polygonum convolvulus
Wild buckwheat, a member of the Buckwheat family, is an annual weed with arrowhead shaped leaves. It has trailing stems that wind around other plants and is often mistaken for field bindweed. Its leaves are heart shaped, alternate and more pointed than those of field bindweed. The leaves have an inconspicious papery sheath that encircles the stem at the base of each petiole. Stems can be 8 - 40" long. In contrast to field bindweed, wild buckwheat has small, green flowers in the leaf axils. Seed are triangular, black and slightly roughened. Seed are the sole source of reproduction.
Wild Proso Millet, Panicum miliaceum
Wild proso millet, a member of the Grass family, is an annual, reproducing by seed. Although proso millet is grown in Colorado as a crop, the wild species is very different and is on the Colorado noxious weed list. Seed germination is in the spring and throughout the summer when soil temperatures reach 68 F. Seed germinate and emerge from the soil as deep as 4" below the surface, but are equally able to germinate closer to the soil surface. Once in the soil, wild proso millet seed can remain viable for five or more years. Wild proso millet plants range in height from 1' in dry areas to 4 - 6' on irrigated sites. Stems of wild proso millet have an abundant hairs located at right angles to the stem. As plants grow larger, they lodge and put down additional roots wherever stem joints touch the ground. Plants can begin flowering in July and continue throughout the summer. The inflorescence produced by wild proso millet is large and bushy. Seed matures in late August through September. Once mature, it readily shatters when the plant is disturbed. Plants can produce 400 - 12,000 seed per square foot, depending upon the degree of plant competition.
Key Weed Management Strategies
Cultural Controls
Sugarbeets are poor competitors with weeds, so it is important not to plant sugarbeets in fields that have been heavily infested. Narrow row widths allow sugarbeets to overshade and out compete emerging weeds. Hand cultivation is also an option for weed control in sugarbeet beds.
Herbicides-
Pesticide: clethodim (Select)
Pesticide: clopyralid (Stinger)
Pesticide: cycloate (Ro-neet 6E)
Pesticide: desmedipham + phenmedipham (Betamix)
Pesticide: desmedipham + ethofumesate + phenmedipham* (Progress)
Pesticide: EPTC (Eptam)
Pesticide: ethofumesate (Nortron SC)
Pesticide: glyphosate (many)
Pesticide: quizalofop (Assure II)
Pesticide: sethoxydim (Poast)
Pesticide: triflusulfuron (Upbeet)
Critical Pest Management Issues
Fungicide resistance management is important in sugarbeets. For control of cercospora leaf spot, thiophanate methyl should be applied only once per season, and should be rotated with triphenyltin hydroxide, mancozeb and maneb. Tetraconazole has a section 18 label for sugarbeets for 2000 through 2003 for Cercospora.
Scout for army cutworms; serious problems occur when wheat is grown through the winter and sugarbeets are planted directly into the cover crop.
ALS resistant kochia is a serious problem that is not adequately managed. Cross and multiple resistance needs to be explained more thoroughly and resistance warnings need to be included on labels to achieve success.
ALS herbicide resistance can be selected for very quickly, even after two applications. More commonly, population pressure due to consecutive applications or continuous production of the same crop year after year using only ALS herbicides selects for resistance. In many situations, resistance is selected for along right-of-ways and then resistant biotypes move into agricultural fields. It is important to rotate herbicide modes of action to prevent future cases of herbicide resistance.
Weeds, diseases, and insects can all develop resistance over time to pesticides. When the same pesticide is used consecutively over a period of time, the target pest can become resistant to that pesticide and render the pesticide obsolete.
Key Diseases
Aphanomyces Root Rot and Black Root, Aphanomyces cochlioides
Aphanomyces root rot can cause problems both in the seedling and in the mature root of beet. Black root is the seedling stage characterized by grayish, water-soaked lesions near the soil line. These lesions often turn black and infection can extend up to the cotyledons, causing cotyledons to become black and thread-like. On mature roots, the foliage wilts, turns dull green and may eventually become yellowed or take on a scorched appearance. On roots, yellowish-brown water soaked lesions become dark brown to black. Infection usually starts at the root tip. Disease severity and intensity depends largely on available soil moisture and temperature. Management includes planting early into cool soils and the use of seed treatments with hymexazol (Tachigaren) to protect seedlings. Avoid unnecessary irrigation and avoid plant stress.
Cercospora Leaf Spot, Cercospora beticola
Cercospora leaf spot is a serious leaf disease of sugarbeet. Symptoms initially occur on older leaves and then progress to the younger leaves. The symptoms are leaf spots about 0.125" in diameter with ash colored centers and purple to brown borders. These leaf spots are distinguished from other leaf spot diseases of sugarbeet by the appearance of black spore-bearing structures (sporophores) in the centers of the spots. The sporophores can be seen as black dots with the aid of a hand lens. During moist periods, the black dots will be covered with colorless fuzzy mass of spores. As the disease progresses numerous individual spots coalesce to form large areas of dead tissue. Severely infected older leaves wither and die. This disease is only a problem in wet years and is directly related to leaf surface wetness and high nighttime temperatures. Plant spacing is critical to reducing wetness. Crop rotation and tillage decrease inoculum carryover in the soil. Host resistance can aid in management.
Beet Curly Top Virus, (BCTV)
Curly top is a viral disease that is transmitted and spread by the sugarbeet leafhopper. The growing region is divided into zones based on the historic severity of the disease. Only varieties of sugarbeets that have been tested and demonstrated sufficient disease resistance for each specific zone are allowed to be planted. Leaves of susceptible cultivars are dwarfed, crinkled, rolled inward, and cupped upward. It is favored by hot and dry conditions. Resistance, early planting, weed management, and vector management or scouting based on economic thresholds are recommended techniques for controlling this disease.
Fusarium Yellows, Fusarium oxysporum f. sp. betae
Fusarium yellows symptoms are drooping and epinasty (downward twisting) of leaves followed by yellowing, stunting and death. Symptoms may be one sided and progress upward, killing foliage. A cross section of the stem near the base will have characteristic reddish vascular discoloration. Fusarium wilt is favored by high air and soil temperatures and occurs most frequently in temperate areas. This fungus survives in soil and plant debris as chlamydospores, survival structure of the fungus. It can also survive in infected weeds. This disease is a major problem in Colorado. Control is primarily through use of resistant cultivars. Managing nematodes can aid in control.
Powdery Mildew, Erysiphe polygoni (E. betae)
Powdery mildew causes small, white powdery spots on the bottom of older leaves when the plant is young. It can occur under wet or dry conditions and does not require a film of water on the leaf surface for infection to take place. In warm, dry weather the fungus can spread to all leaves and older leaves turn yellow, become necrotic and die. Spores are produced continuously day and night throughout the summer. Powdery mildews are host specific. They also produce a sexual structure, an ascoma, which produces ascospores in the spring. Management of powdery mildew is primarily through use of resistant cultivars. Protectant fungicides such as sulfur can be used when necessary and are most effective when applied with good leaf coverage at first sight of the characteristic powdery spots.
Rhizoctonia Crown Rot, Rhizoctonia solani
Symptoms of root and crown rots are seen first in the above ground parts of the plant as chlorosis, wilting, stunting, necrosis, collapse, reduced yield, and plant death. The affected roots, crown or stem have darkened lesions and cankers. In Colorado, this disease is worse when sugarbeets have to be replanted into warmer soils. Fungicide seed treatment such as chloroneb combined with good soil preparation will best manage the disease. Careful cultivation avoiding piling up soil around stem and in the crown is very important in integrated management of this disease. Crop rotation and clean seed are always key factors in a successful integrated management program. Resistant cultivars are available and chemical control is now available with some efficacy.
Rhizomania, Beet Necrotic Yellow Vein Virus (BNYVV)
Rhizomania is a serious issue in Colorado. The most obvious symptom is a mass of fine, hairy secondary roots that consist of a mixture of dead and healthy roots. Early season infection may result in severely stunted fleshy roots. Leaf symptoms are most often a general chlorosis that may reveal infested areas in the field. Veinal yellowing and necrosis is diagnostic of rhizomania. Management is primarily achieved through disrupting the life cycle of the vector which is a soil-borne fungus, Polymyxa betae. Planting early, avoiding over use of irrigation and using resistant varieties will help reduce problems associated with BNYVV. Soil fumigation and/or soil solarization can be beneficial where allowed or cost effective.
Sugarbeet Cyst Nematode, Heterodera schachtii
There are three different species of nematodes that are of concern to sugarbeet growers. The most common is the Sugarbeet cyst nematode, Heterodera schachtii. Sugarbeets are sometimes also affected by the root knot, Meloidigyne spp., and the false root knot nematode, Nacobbus dorsalis. However, both of these are usually quite localized and normally do not represent too much of an economic threat. Nematodes survive in soil as cysts and on weed hosts. They are spread by irrigation water and contaminated soil on machinery. In general, above ground symptoms are not readily noticeable. However symptoms from severe nematode damage appear as stunted growth, chlorosis, and wilting during periods of high temperature and moisture stress. These symptoms can be similar to those induced by nutrient deficiencies. Root symptoms of nematode infection vary with the kind of nematode. Heterodera schachtii, or Sugarbeet cyst nematode, is a small, pinhead-sized cyst that attaches to the feeder roots. Plants sprawl and turn yellow and leaf petioles wilt above ground. Soil temperature between 55 - 80 F favor nematodes. Plants appear stunted or dead. Cyst nematodes are present throughout much of our beet growing area. Three to four year crop rotations are recommended to help manage populations, but in many areas treatment is still necessary. If unchecked, yield losses can be extremely high from sugarbeet cyst nematode damage. Nematicides such as dichloropropene, crop rotation, and resistant varieties are the primary tools available for nematode control.
Additional Diseases
Damping Off, Aphanomyces cochlioides, Cylindrocladium spp., Fusarium spp., Phoma betae, Pythium spp., and Rhizoctonia solani
Soil-inhabiting fungi cause these diseases. They are characterized by missing or collapsed plants. When pre-emergence damping-off occurs, seedlings fail to break the soil surface. The germinating seed rots while still in the ground. With post-emergence damping-off, seedlings will rot at the soil line. The stem appears pinched and plants fall over. The developing root system rots and plants collapse. Seedling diseases are problems when soils are cold and wet at or immediately following planting. These conditions can delay germination or stress developing seedlings, which allows pathogens to attack. Crusting caused by poor soil preparation or hard rain, or excessive trash on the surface also contributes to disease. Fungicide seed treatment such as captan or mefenoxam combined with avoiding cold wet soils and good soil preparation will best manage these diseases. Cultural practices such as avoiding piling soil around stem and rotation can help in the control of this disease. A key management tool is the use clean seed.
Pythium Root Rot, Pythium spp.
Pythium root rot causes pre-emergence and post-emergence damping off. Infection rates can be high, particularly during the periods of cool, wet weather and can lead to germination failure. Infected seedlings wilt, turn brown and die resulting in poor stands. Seedlings that are attacked at the ground level develop a water-soaked, discolored stem and topple over. Infected plants seldom recover. Pythium develops as white mycelium, branching off and forming reproductive structures. The spores move through water to the host, surviving best on dead plant and animal matter, but able to survive on living plants in particularly wet soils. The fungus enters plant cells, consumes cellular material and kills the cells. If the initial infection of a plant occurs at a more mature stage of plant development, the host is able to resist the fungal growth. However, at more immature stages, such as seed and young seedlings, the fungus is able to grow readily into the plant tissues and kill the plant with yield losses up to 100%. Young roots can be attacked by fungus at any stage of plant growth. If there is a history of this disease in a field, it would be better to use sprinklers than to furrow irrigate. Currently, there is no resistance used to control this disease, but rhizomania resistant varieties have proven to be more tolerant due to healthier root systems.
Key Disease Management Strategies
Cultural Controls
Scout plants for disease occurrence. Disease models are available for some diseases to determine infection periods and fungicide application requirements.
Rotating fields out of sugarbeet production for 3 - 4 years, accurate timing and application of irrigation water, and timely planting all improve pest management in sugarbeet crops.
Nematicides-
Pesticide: dichloropropene + chlopicrin (Telone C-17)
Pesticide: dichloropropene (Telone II)
Fungicides-
Pesticide: captan (Captan 30DD)
Pesticide: captan (Captan 400)
Pesticide: copper hydroxide (Kocide 101)
Pesticide: copper sulfate (Basicop)
Pesticide: hymexazol (Tachigaren 70WP)
Pesticide: mancozeb (Dithane M-45)
Pesticide: mancozeb (Penncozeb 75 DF)
Pesticide: maneb (Maneb 80WP)
Pesticide: maneb (Manex)
Pesticide: mefenoxam (Ridomil Gold EC)
Pesticide: mefenoxam (Ridomil Gold GR)
Pesticide: sulfur (Microthiol Disperss)
Pesticide: tetraconazole (Eminent 125SL)
Pesticide: thiophanate methyl (Topsin M WSB)
Pesticide: triphenyltin hydroxide (Super Tin 80W)
Scott Nissen, Sugarbeet Weed Specialist, Colorado State University, Department of Bioagricultural Sciences, Fort Collins, CO 80523, (970) 491-3489, snissen@lamar.colostate.edu
Linda Hanson, Plant Pathologist, Sugarbeet Research, 1701 Centre Avenue, Fort Collins, CO 80526
Authors
Sandra K. McDonald, EditorLisa Downey