Sugarbeet

A. W. Cattanach1, A. G. Dexter1, and E. S. Oplinger2

1Extension Sugarbeet Specialists, North Dakota State University, Fargo, ND 58105, and University of Minnesota Extension Services, St. Paul, MN 55108.
2Department of Agronomy, College of Agricultural and Life Sciences Cooperative Extension Service, University of Wisconsin-Madison, WI 53706.
July, 1991.

I. History:

Sugarbeet (Beta vulgaris) growing for sucrose production became successful in the United States starting about 1870. Earlier attempts at sugarbeet production were not totally successful. Once a viable industry was established, sugarbeets were grown in 26 states. About 1,400,000 acres were produced in 14 states in 1990. Minnesota and North Dakota produced about 550,000 acres. Other leading sugarbeet states are Idaho, California, Michigan, Nebraska, Wyoming, Montana, Colorado and Texas. Canada produces sugarbeets in Manitoba and Alberta. Russia leads worldwide production of sugarbeets with nearly 8,500,000 acres followed by Poland, France, West Germany and Turkey with about 1,000,000 acres each. The United States beet sugar industry has experienced great change in the last three decades. A total of 10 beet processors operated 53 factories in 18 states in 1973 while nine companies operated only 36 factories in the United States in 1990.

II. Uses:

Sugarbeets are used primarily for production of sucrose, a high energy pure food. Man's demand for sweet foods is universal. Honey was the main sweetener for primitive man. Trade in sugar from sugarcane can be traced to primitive times too. The sugarbeet was recognized as a plant with valuable sweetening properties in the early 1700s.

A. Human Food:

Sucrose from sugarbeets is the principal use for sugarbeets in the United States. Sugarbeets contain from 13 to 22% sucrose. Sucrose is used widely as a pure high energy food or food additive. High fiber dietary food additives are manufactured from sugarbeet pulp and major food processors in the United States have used these dietary supplements in recently introduced new products including breakfast cereals.

B. Livestock Feed:

Sugarbeet pulp and molasses are processing by-products widely used as feed supplements for livestock. These products provide required fiber in rations and increase the palatability of feeds. Sugarbeet tops also can be used for livestock feed. Sheep and cattle ranchers allow grazing of beet fields in the fall to utilize tops. Cattle and sheep also will eat small beets left in the field after harvest but producers grazing livestock in harvested fields should be aware of the risk of livestock choking on small beets.

Beet tops (leaves and petioles) also can be used as silage. Sugarbeets that produce 20 tons/acre of roots also produce a total of about 5 tons/acre of TDN in the tops. Tops are an excellent source of protein, vitamin A, and carbohydrates but are slightly inferior to alfalfa haylage or corn silage for beef cattle. Tops are equal to alfalfa haylage or corn silage for sheep. Beet top silage is best fed in combination with other feeds. Tops should be windrowed in the field and allowed to wilt to 60-65% moisture before ensiling. See Morrisons Feeds and Feeding Handbook for a detailed description of the nutrient content of sugarbeet tops and roots.

C. Industrial Uses:

Molasses by-products from sugarbeet processing are used widely in the alcohol, pharmaceuticals, and bakers yeast industries. Waste lime from the processing of sugarbeets is an excellent soil amendment to increase soil pH levels. Waste lime is a good source of P & K plant nutrients. Treated processing waste water also may be used for irrigation.

III. Growth Habit:

Sugarbeet is a biennial plant which was developed in Europe in the 18th century from white fodder beets. Sugar reserves are stored in the sugarbeet root during the first growing season for an energy source during overwintering. The roots are harvested for sugar at the end of the first growing season but plants which overwinter in a mild climate will produce flowering stems and seed during the following summer and fall. Sugarbeet roots will not survive the winter in North Dakota, Minnesota, and Wisconsin. Sugarbeet is a summertime crop in the northern United States and a winter or summer crop in more southern, semi-arid regions. Sugarbeet seed for the United States is produced in Oregon where the climate is cool enough for vernalization but warm enough for the roots to live through the winter.

The plant has a taproot system that utilizes water and soil nutrients to depths of 5 to 8 ft. As sugarbeet plants emerge, a pair of cotyledons unfold. Successive leaves develop in pairs throughout the growing season. The life expectancy of sugarbeet leaves varies from 45 to 65 days and is temperature dependent.

Photothermal induction is necessary to bring about complete reproductive development of the plant. The sugarbeet normally is a diploid plant. It is cross pollinated with wind being the effective agent.

IV. Environment Requirements:

A. Climate:

Sugarbeets have adapted to a very wide range of climatic conditions. Sugarbeets primarily are a temperate zone crop produced in the Northern Hemisphere at latitudes of 30 to 60o N. Sugarbeets can be produced in hotter and more humid environments, however, problems with insects, disease and low quality of the crop are more common in such geographical areas.

The sugarbeet plant grows until harvested or growth is stopped by a hard freeze. Sugarbeets primarily grow tops until the leaf canopy completely covers the soil surface in a field. This normally takes 70 to 90 days from planting. Optimal daytime temperatures are 60 to 80oF for the first 90 days of plant growth. Regions with long day length are most suitable for sugarbeet growth. The most favorable environment for producing a sugarbeet crop from 90 days after emergence to harvest is bright, sunny days with 65 to 80oF temperatures followed by nighttime temperatures of 40 to 50oF. These environmental conditions maximize yield and quality in a sugarbeet crop.

B. Soil:

Sugarbeets are well adapted to a wide range of soil types. In the United States, sugarbeets are produced on coarse textured sandy soils to high organic matter, high clay content, silty clay or silty clay loam soils. A soil free or nearly free of stones is particularly desirable. Stones cause problems for sugarbeet planting, thinning, harvesting and processing equipment. Dryland sugarbeet production generally is limited to soils with high water holding capacities in areas with 20 in. of rainfall or more. Sugarbeets are successfully produced under irrigation in regions with very low rainfall.

V. Cultural Practices:

A. Seedbed Preparation:

Field selection and seedbed preparation are critical to establishment of the sugarbeet crop. Objectives are to manage crop residues effectively, minimize erosion, improve soil structure to meet needs of the crop and eliminate early season weeds.

Fall tillage should be matched to soil type, amount and type of previous crop residue present, and be compatible with soil conservation requirements. Mold board plows, chisel plows, disks and field cultivators all have been successfully used for primary fall tillage. Fall tillage systems should maintain enough residue on the soil surface to prevent erosion or be compatible with cover cropping systems for erosion control. Spring tillage should be kept to an absolute minimum. Objectives are to preserve seedbed moisture, maintain enough crop residues on the soil to stop erosion, and reduce the chance of wind damage to weak sugarbeet seedlings as they emerge. The spring seedbed should be as level as possible and firm to well packed to allow good seed to soil contact when planting. Common spring tillage tools are light harrows, multiweeders, and combination Danish tine, harrow, rolling basket tillage tool systems. Spring tillage should be only 1 to 2 in. deep. Planting should be done as quickly as possible after spring tillage before seedbed drying can occur. Sugarbeets are planted only 0.75 to 1.5 in. deep.

Sugarbeets have been successfully planted with no-till, with strip tillage in previous crop residues, and other reduced tillage systems. These tillage alternatives often require specialized equipment, greater planning and better management to be successful.

B. Seeding Date:

Research in North Dakota, Minnesota, Michigan and other states indicates highest yields and crop quality are attained with early planting. Growers generally accept some risk of early frost damage and plant early. Optimum planting dates in Minnesota, North Dakota, and Wisconsin are from April 20 to May 10. Sugarbeets have been successfully planted as early as April 1st. They may be planted as late as June 10 and still produce a harvestable crop. Yields decline about 1.5 tons/week with each week delay in planting after May 10. Seedling sugarbeet plants have good tolerance to mild frosts and have survived temperatures in the mid-twenty degree range.

C. Method and Rate of Seeding:

Sugarbeets are planted with precision row crop planters. Plate and cell wheel planters or newer vacuum or air planters all work well. Sugarbeets may be planted to thin to a final stand or space planted to a desired final plant population. Seeding rates vary from 1 to 2 lbs of seed/acre. Sugarbeet planters should not be operated at more than four miles per hour. Planting speeds greater than four miles per hour result in increased skips, increased seed doubles or triples and seed damage. Sugarbeet seed should not be planted greater than 1.5 in. deep.

D. Row Width and Plant Populations:

Narrow row widths produce higher yields and quality than wide rows. Sugarbeets in narrow rows compete better with weeds also. Optimum row widths are 18 to 24 in., with 22 in. rows being most common. Sugarbeets may be planted in 30 in. rows for equipment convenience and compatibility with other row crops in rotation. However, sugarbeets planted in 30 in. rows commonly yield 400 to 600 lbs less recoverable sugar per acre than in 22 in. rows, with the same harvest populations. Also, higher more uniform plant populations, which will result in greater yield and quality, are easier to establish on narrow rows.

Sugarbeet plant populations should be from 30,000 to 40,000 uniformly spaced plants per acre at harvest. These populations should produce very good yields of easily harvested high quality sugarbeets. Growers can expect plants to be established from only 60 to 70% of the seed planted. Loss of 5 to 15% of established seedlings can be expected between planting or thinning and harvest depending on growing conditions.

E. Crop Rotations:

Yields and quality usually are highest when sugarbeets follow barley or wheat in the crop rotation. Yields usually are high when sugarbeets follow corn, potatoes or summer fallow in rotation, but higher than desirable residual soil nitrogen levels may follow these crops and reduce sugarbeet quality. Three years research in Minnesota indicated sugarbeet yielded significantly less when following soybeans versus barley in rotation. One year of research indicated sugarbeet yields also were reduced following dry edible beans in rotation.

F. Fertility and Cultural Practices:

Sugarbeets do not grow well on highly acidic soils and grow best on soils with a pH of 6.0 to 8.0. Sugarbeet culture on soils with pH lower than 6.0 should not be attempted until liming raises the pH to 7.0 or greater.

Profitable sugarbeet production depends largely on a high sucrose content/high tonnage crop. To accomplish this, growth-limiting factors such as soil fertility must be managed effectively.

Sugarbeets are unique in their nitrogen (N) requirements. Too little nitrogen results in poor leaf canopies, premature yellowing and reduced yields, while too much nitrogen leads to a reduced sucrose content, increased impurities and lowered sucrose extraction. For proper nitrogen management, pregrowing season soil nitrate-nitrogen (NO3-N) should be determined in a reputable laboratory that uses appropriate procedures and interpretations. NO3-N is mobile in the soil so residual nitrogen level should be determined annually. Phosphorus and potassium should be determined every three to four years.

Sugarbeet quality involves two concepts: the percent sucrose in the root and the level of impurities in the root, both of which affect sucrose extraction by the processor. Production of high quality sugarbeets is especially important to growers whose payment is based on the extractable sucrose content of their beets.

Proper nitrogen fertilizer use normally increases yield of both roots and sucrose and also may increase impurities and decrease the percent sucrose in the root. Use soil test information to select fields with nitrogen levels suited to expected yields, and to select fertilizer rates appropriate for expected yield goals. Excessive amounts of either residual or fertilizer nitrogen usually significantly lowers beet quality. Sugarbeets require 8 to 9 lbs of nitrogen/ton to produce a high quality, good yielding crop.

Table 1. Nitrogen, phosphate and potash recommendations for sugarbeets1 .
    Phosphorus Potassium
    P Soil Test Levels (lb/acre) K Soil Test Levels (lb/acre)
    L
0-9
M
10-19
H
20-29
VH
Over 30
L
0-99
M
100-199
H
200-299
VH
Over 300
ton/acre lb/acre/2 ft1 -------- P2O5 lb/acre -------- ---------- K2 O lb/acre ----------
16 95 60 35 10 0 85 50 15 0
17 100 60 35 10 0 90 55 20 0
18 110 65 40 15 0 95 55 20 0
19 115 70 40 15 0 100 60 20 0
20 120 75 45 15 0 105 65 20 0
22 130 80 50 15 0 115 70 25 0
*Subtract amount of NO3-N in top 2 feet of soil from these figures to determine the amount of N fertilizer to apply. 1All recommendations are for broadcast applications.

When selecting a sugarbeet yield goal and requesting fertilizer recommendations, remember that recoverable sugar is the product desired. Over-fertilization, particularly with nitrogen, can result in poor quality beets and reduced net returns. Therefore, judicious use of manageable factors such as nitrogen fertilizer, early planting, even spacing, adequate plant populations, weed control, timeliness of operations, disease and insect control all will improve recoverable sugar yield. A good method for selecting a yield goal is to use a yield approximately three tons/acre lower than the greatest yield produced on your farm or in your area.

Recent research in Minnesota and North Dakota indicated early season growth and/or yield responses to starter fertilizer occurred about 40% of the time. Significant responses are most likely to occur when soils test very low to low in phosphorus or have low levels of available nitrogen in the top 6 in. of soil.

Sugarbeet seeds and seedlings are sensitive to fertilizer salts. Germination damage may occur if excess nitrogen or potassium fertilizer is placed in direct contact with seed. In some areas, straight phosphate fertilizer materials may not be available in sufficient quantities. In this case, use monoammonium phosphate (11-48-0) or 10-34-0 liquid as a starter fertilizer. Seed germination reduction should be negligible from 5 or less pounds of nitrogen per acre in contact with beet seed and any slight effect would be more than offset by the improved yields from the banded phosphorus application on very low-testing soils. Do not apply more than 5 to 6 lbs/acre of nitrogen plus potassium as a starter in contact with the seed.

Sugarbeets growing on soils that test very low in phosphorus and/or potassium depend heavily on applied fertilizer. On soils testing medium or above, the crop is much less dependent on applied fertilizer. Fertilizer is applied on these soils to replace nutrients removed by the crop and/or as a starter to get the crop off to a fast start, especially in cool, cloudy springs. On very low testing soils where the plants depend largely on fertilizer for their needs, the method of application will influence the amount of fertilizer that plants can recover. Broadcast fertilizer is thoroughly mixed with the soil and, as a result, some is positionally unavailable to plant roots. Band or drill row fertilizer is applied closer to the seed and can be recovered more efficiently by the crop.

Sugarbeets are among the crops least susceptible to secondary and micronutrient deficiencies. The exception may be a susceptibility to boron and manganese shortages. Zinc deficiency has been reported on infrequent occasions in Minnesota. Responses to other micronutrients have not been reported or demonstrated. A soil test for these nutrients will answer questions that arise about possible needs for manganese, copper, or iron.

Calcium deficiency may be observed in sugarbeets in Minnesota and North Dakota. However, the deficiency apparently is a physiological problem. Soils in this area are high in calcium and application of calcium-containing fertilizers will not correct the deficiency. Yield losses due to this problem have not been documented.

G. Variety Selection:

Commercial sugarbeet variety development has been exclusively by private sugar and seed companies in the United States. American Crystal Sugar Company, Moorhead, Minnesota conducts the most comprehensive variety trials in the United States.

American Crystal's coded variety trials are designed to give an unbiased evaluation of the genetic potential of all sugarbeet variety entries while other variables (stand, fertility, moisture levels, etc.) are kept constant. These evaluations are used to establish a list of approved varieties which insures the use of the most productive varieties to maximize returns to the growers and sugar companies.

H. Weed Control:

Sugarbeets are poor competitors with weeds from emergence until the sugarbeet leaves shade the ground. Emerging sugarbeets are small, lack vigor, and take approximately two months to shade the ground. Thus, weeds have a long period to become established and compete. Sugarbeets are relatively short even after they shade the ground so many weeds that become established in a field prior to ground shading will become taller than the sugarbeets, shade the sugarbeets, and cause severe yield losses. To avoid yield loss from weed competition, weeds should be totally controlled by four weeks after sugarbeet emergence and weed control should be maintained throughout the season.

A combination of cultural, chemical, and mechanical weed control methods should be used to maximize weed control in sugarbeets. Some weed species such as kochia, common mallow, common milkweed, and velvetleaf are difficult or impossible to control selectively in sugarbeets with herbicides. These weeds in particular, and all weeds in general, should be effectively controlled in other crops in the rotation. Spot spraying or hand weeding small areas should be used to prevent establishment of problem weeds. Sugarbeets should not be planted on fields badly infested with problem weeds.

Cultivation with a row crop cultivator is a universal and essential weed control method in sugarbeets. Also, the rotary hoe or spring tine harrow can be used to remove small weeds from well rooted sugar beets. Hand weeding is still an important method of weed control in sugarbeets with 76% the acres in Minnesota and Eastern North Dakota receiving some hand weeding in 1989. The decision on using hand weeding or other methods of weed control should be based on expected economic returns. Generally herbicides will be more cost effective than hand weeding in moderate to heavy weed densities. Hand weeding may be more cost effective in low weed densities, especially if the target weed species are herbicide tolerant or too large for effective control.

1. Preemergence Contact or Tillage Substitution Herbicides: Glyphosate (several trade names) can be applied before sugarbeets emerge to emerged weeds at 0.19 to 0.75 lb/acre (0.5 to 2 pt/acre). Use the higher rate on larger weeds, more resistant weeds, or if the plants are under moisture stress. Use 0.75 lb/acre to control living small grain cover crops. When low rates of glyphosate are used, apply in 3 to 10 gallons of water per acre by ground or in 3 to 5 gpa by air. Delay tillage for at least 3 days after treatment. Glyphosate is a non-selective translocated postemergence herbicide with no soil residual activity. A non-ionic surfactant should be used with glyphosate.

Paraquat (Gramoxone Extra) can be applied before sugarbeets emerge to emerged weeds at 0.62 to 0.94 lb/acre (2 to 3 pt/acre). Apply in 5 to 10 gpa of water by air or in 20 to 60 gpa by ground. Paraquat is a non-selective contact herbicide with no soil residual activity. A non-ionic surfactant should be used with paraquat.

2. Soil-applied Herbicides: Good weed control with preemergence (non-incorporated) herbicides requires rainfall after application. Herbicides which are incorporated into the soil surface usually require less rainfall after application for effective weed control than unincorporated herbicides. Weeds emerging through a preemergence herbicide treatment may be controlled by rotary hoeing or harrowing without reducing the effect of the herbicide unless the harrow or rotary hoe removes the herbicide from a treated band.

The reasons for using soil-applied herbicide in sugarbeets include the following:

1) To reduce early season weed competition.

2) To make postemergence herbicides more effective by increasing weed susceptibility and by reducing the total weed population.

3) To provide weed control if unfavorable weather prevents timely cultivations or postemergence herbicide applications.

4) A single herbicide treatment usually will not give total weed control. A preemergence or preplant incorporated herbicide followed by postemergence herbicides often will improve weed control compared to preemergence or preplant incorporated herbicides alone or postemergence herbicides alone.

Incorporation of Herbicides: Many herbicides applied before crop and weed emergence need to be incorporated to give optimum weed control. Included in this group are cycloate (Ro-Neet) and EPTC (Eptam). Weed control from ethofumesate (Nortron), pyrazon (Pyramin), and diethatyl (Antor) generally is improved by incorporation.

Cycloate (Ro-Neet) and EPTC (Eptam) should be incorporated immediately after application regardless of whether the liquid or granular formulation is used. Ethofumesate (Nortron), diethatyl (Antor), and pyrazon (Pyramin) may be used preemergence but incorporation usually improves weed control, especially on fine-textured soils or with limited rainfall after application. Incorporation may reduce weed control if heavy rains follow application and incorporation may increase sugarbeet injury compared to surface application. Experience indicates that lack of rainfall is more common than excess rainfall following planting.

An estimate of the efficiency of an incorporating tool can be obtained by operating the tool through flour or lime which has been spread thickly over the soil. A thorough incorporation should cover most of the flour or lime and give uniform mixing through the soil. Several tillage tools have been used successfully for the incorporation of herbicides. Some herbicides require more thorough incorporation than others and the incorporation method should be matched to the herbicide.

Cycloate and EPTC require a thorough incorporation and should be incorporated by one of the following methods or a method which will incorporate similarly.

a) A tandem disk should be set at a depth of 4 to 6 in. for EPTC or cycloate. Operating speed should be 4 to 6 mph. Tandem disks with disk blades spaced 8 in. or less and disk blade diameter of 20 in. or less have given good herbicides incorporation. Larger disks often give streaked incorporation and poor weed control.

b) Field cultivators of various types may be used. These should have overlapping sweep shovels with at least three rows of gangs and the operating depth should be 4 to 6 in. for EPTC and cycloate. A harrow should follow the field cultivator. The operating speed necessary to achieve a satisfactory incorporation will vary somewhat depending on the type of field cultivator but the speed usually will be 6 to 8 mph.

c) Field cultivators with Danish tines plus rolling crumblers behind have given good herbicide incorporation. These tools should be operated 4 in. deep and at 7 to 8 mph or faster. Adequate incorporation with one pass may be possible with these tools if soil conditions are ideal for herbicide incorporation. However, a second incorporation may be good insurance against poor weed control.

d) Power driven rototiller-type equipment will give adequate incorporation when set to operate at a depth of 2 to 3 in. at the manufacturer's recommended ground speed.

A single incorporation with a power driven rototiller is sufficient for cycloate or EPTC. However, a second tillage at right angles to the initial incorporation should be done if the disc or field cultivator is used. The second incorporation has two purposes:

a) Most of the herbicide left on the surface after the first incorporation will be mixed into the soil with the second tillage.

b) The second tillage will give more uniform distribution of the herbicide in the soil which will improve weed control and may reduce crop injury.

Ethofumesate, diethatyl, and pyrazon do not require deep incorporation. A tillage tool operating at a minimum depth of 2 in. will give adequate incorporation if the tool mixes the herbicide uniformly through the soil.

EPTC (Eptam) preplant incorporated in the spring at 2 to 3 lb/acre (2.3 to 3.4 pt/acre) or fall applied at 4 to 4.5 lb/acre (4.5 to 5.25 pt/acre) gives good control of annual grasses and certain broadleaf weeds. EPTC sometimes causes sugarbeet stand reduction and temporary stunting. However, no yield reduction will result if enough sugarbeets remain to obtain an adequate plant population after thinning. EPTC should be used with extreme caution on sugarbeets grown in loam or coarser-textured soils with low organic matter levels because a safe EPTC rate is difficult to predict on such soils.

Cycloate (Ro-Neet) spring applied at 3 to 4 lb/acre (4 to 5.3 pt/acre) or fall applied at 4 lb/acre (5.3 pt/acre) gives weed control similar to EPTC. EPTC tends to give better weed control than cycloate on fine-textured, high organic matter soils or under relatively dry conditions while cycloate gives better control than EPTC when spring rainfall is adequate to excessive. Cycloate causes less sugarbeet injury than EPTC and is thus safer for use on more coarse textured, low organic matter soils.

EPTC (Eptam) plus cycloate (Ro-Neet) has less potential for sugarbeet injury than EPTC alone and is less expensive per acre than cycloate alone. The rate of application of the mixture must be adjusted for soil texture and organic matter. Suggested fall applied rates are: cycloate alone at 4 lb/acre on soils with less than 3 % organic matter, EPTC + cycloate at 1 + 3 lb/acre on loam or coarser soils with 3 % organic matter, 1.5 to 2.5 lb/acre on loam to clay loam soils with 3 to 4 % organic matter, 2 + 2 lb/acre on clay loam soils with 3.5 to 4.5 % organic matter, and 2.5 + 2.5 lb/acre on clay or clay loam soils with over 4.5 % organic matter. Suggested spring applied rates are: cycloate alone at 3 lb/acre on loam or coarser soils with 3 % or less organic matter, EPTC + cycloate at 1 + 2.5 lb/acre on loam or coarser soils with 3 to 3.5 % organic matter, 1.5 + 2.5 lb/acre on loam to clay loam soils with 3.5 to 4.5 % organic matter, and 2 + 2 lb/acre on clay loam or finer soils with 4 % or more organic matter. These rates may need to be adjusted on certain fields or with certain incorporation tools based on individual experience. EPTC, cycloate, or EPTC + cycloate require immediate incorporation for best weed control.

Pyrazon (Pyramin) spring applied at 3.1 to 7.6 lb/acre (6 to 14.5 pt/acre) controls most broadleaf weeds. Pyrazon has been less effective on soils with more than 5% organic matter. Weed control from pyrazon generally increases as soil organic matter content decreases. Shallow incorporation generally improves weed control from pyrazon. High amounts of rainfall after application improves weed control from pryazon.

Ethofumesate (Nortron) at 3 to 3.75 lb/acre (16 to 20 pt/acre) gives good control of several broadleaf and grassy weeds, is especially effective on redroot pigweed, but is weak on yellow foxtail. Ethofumesate generally gives less sugarbeet injury than EPTC (Eptam) especially on more coarse textured, low organic matter soils. Ethofumesate may be applied preemergence but incorporation generally improved weed control in tests in North Dakota and Minnesota. Preemergence applications of ethofumesate will give good weed control when relatively large amounts of rain follow application. The exact amount of rain needed is not known but field observations indicate that at least 1 in. of rain is needed to give best results from preemergence ethofumesate. Coarse textured, low organic matter soils require less rain for activation than fine textured, high organic matter soils. Ethofumesate often has a residue the year following use on sugarbeets. Crops most likely to be damaged by ethofumesate residue are wheat, barley, and oats. Moldboard plowing usually eliminates carryover injury. Ethofumesate should be applied in a band to reduce cost and reduce carryover.

Diethatyl (Antor) spring applied at 4 to 6 lb/acre (8 to 12 pt/acre) gives good to excellent control of redroot pigweed and prostrate pigweed. Diethatyl generally gives less sugarbeet injury than EPTC (Eptam) especially on coarse textured, low organic matter soils. Diethatyl may be applied preemergence but incorporation generally improved weed control in tests in North Dakota and Minnesota. Preemergence diethatyl will give good weed control if adequate rain follows application. Diethatyl needs amounts of rain similar to ethofumesate as discussed in the previous paragraph.

3. Postemergence Herbicides: Clopyralid (Stinger) at 0.09 to 0.25 lb/acre (0.25 to 0.66 pt/acre) postemergence controls several broadleaf weeds and volunteer crops. Clopyralid at 0.09 to 0.19 lb/acre is most effective when applied to common cocklebur, giant ragweed, marshelder, volunteer sunflower, wild sunflower, volunteer alfalfa, and volunteer soybeans up to the six-leaf stage, common ragweed up to the five-leaf stage and wild buckwheat in the three to five-leaf stage before vining begins. Clopyralid at 0.19 to 0.25 lb/acre is most effective on Canada thistle in the rosette to pre-bud growth stage, but rosette application often gives better control than later application. Clopyralid must be applied to sugarbeets in the two to eight-leaf stage and at least 105 days prior to harvest. Clopyralid is not registered for application by aircraft.

Clopyralid (Stinger) may have a herbicidally active residual in the soil following postemergence application. Wheat, barley, oats, grasses, corn and sugarbeets have good tolerance to clopyralid and can be planted any time following application. Other crops usually can be planted 12 months after treatment. Extreme conditions where topsoil remained cold or dry for extended periods after application may cause herbicidally active residual to persist for more than 12 months. In this case, small areas of lentils or peas should be planted as bioassay species prior to planting more extensive areas of lentils, peas, safflower, potatoes, alfalfa, sunflowers, edible beans, or soybeans. Time of clopyralid application during a season may influence the time of crop seeding the following year. For example, clopyralid applied June 15 would prevent seeding soybeans or edible beans until June 15 or later the following year.

Desmedipham (Betanex) and desmedipham + phenmedipham (Betamix) are postemergence herbicides for the control of annual broadleaf weeds. Sugarbeet injury occasionally occurs from desmedipham and phenmedipham. Sugarbeets with four true leaves are less susceptible to injury than smaller sugarbeets. Sugarbeets gain additional tolerance as they become larger than the four-leaf stage. Desmedipham at 0.25 to 0.5 lb/acre (1.5 to 3 pt/acre) or desmedipham plus phenmedipham at 0.12 to 0.25 plus 0.12 to 0.25 lb/acre (1.5 to 3 pt/acre) may be applied to sugarbeets with less than four leaves. Applications totalling 0.5 lb/acre or less should be followed by a second application in 5 to 7 days if living weeds are present after 5 days. Split application with reduced rates has reduced sugarbeet injury and increased weed control compared to a single full dose application. Risk of sugarbeet injury is reduced by starting application in late afternoon so cooler temperatures follow application. Risk of injury is increased by factors such as recent flooding, high temperature, and a sudden change from a cool, cloudy environment to a hot, sunny environment. Sugarbeets and weeds in fields treated with a soil applied herbicide will be more susceptible to desmedipham and phenmedipham than untreated plants. Desmedipham and desmedipham plus phenmedipham vary in effectiveness on certain weed species.

Endothall (Herbicide 273) at 0.75 to 1.5 lb/acre (2 to 4 pt/acre) gives good control of wild buckwheat, and smartweed. Sugarbeets would have 4 to 6 leaves before application and should not be treated later than 40 days after emergence. Temperatures should be 60 to 80oF at application. Weed control may be poor when weeds are under even slight drought stress.

Sethoxydim (Poast) at 0.1 to 0.5 lb/acre (0.5 to 2.5 pt/acre) plus an oil additive will control annual grasses and suppress perennial grasses. An oil additive must be used for consistently good grass control. Tank mixing sethoxydim (Poast) plus oil additive with desmedipham, phenmedipham, or endothall often gives less grass control, especially of wild oats. Addition of ammonium sulfate at 2.5 lb/acre or 28% nitrogen solution at 0.5 to 1 gpa often will increase grass control especially when the water carrier has high levels of sodium carbonate or sodium bicarbonate. Application rates for several grass species are: 0.1 lb/acre for wild proso millet; 0.2 lb/acre for green foxtail, yellow foxtail, giant foxtail, barnyardgrass, wooly cupgrass, wild oat, or volunteer corn; 0.28 lb/acre for volunteer cereals; and 0.25 lb/acre plus 0.2 lb/acre on regrowth for quackgrass.

Combinations of postemergence herbicides give more broad spectrum and greater total weed control compared to individual treatments. The risk of sugarbeet injury also increases with combinations so combinations should be used with caution. Ethofumesate (Nortron) in combination with desmedipham and desmedipham + phenmedipham has given improved weed control compared to desmedipham or desmedipham + phenmedipham used alone. These combinations increase the risk of sugarbeet injury. Endothall (H-273) has been used at 0.25 to 0.5 lb/acre in combination with desmedipham or desmedipham + phenmedipham to give improved control of wild buckwheat compared to desmedipham or desmedipham + phenmedipham alone. Clopyralid plus desmedipham plus phenmedipham have given control of wild buckwheat, eastern black nightshade, common lambsquarters, and Russian thistle superior to clopyralid alone and to desmedipham or desmedipham plus phenmedipham alone.

4. Layby Herbicides: Trifluralin at 0.75 lb/acre (1.5 pt/acre) is cleared for use on sugarbeets when the sugarbeets are 2 to 6 in. tall and well rooted. Exposed beet roots should be covered with soil before application. Emerged weeds are not controlled. Trifluralin may be applied over the tops of the sugarbeets and incorporated with a harrow, rotary hoe, or cultivator adjusted to mix the herbicide in the soil without excessive sugarbeet stand reduction. Use of trifluralin can reduce the emergence of late season weeds which often cause problems in sugarbeets. EPTC (Eptam) at 3 lb/acre (3.4 pt/acre) is cleared as a layby herbicide for sugarbeets and should be applied similarly to trifluralin. However, the greater volatility of EPTC and the greater need for thorough incorporation make EPTC less likely to be effective as a layby herbicide than trifluralin. EPTC also can be applied by metering the herbicide into irrigation water. EPTC should be applied in the first irrigation after the last cultivation of the season.

I. Diseases and Their Control:

Sugarbeet yield losses are caused by seedling blights, root rots and foliar diseases. Using appropriate control methods will eliminate or reduce losses from diseases.

The most common seedling pathogens are soilborne fungi. These include Aphanomyces cochlioides, Rhizoctonia solani and several Pythium species. Phoma betae is a seedborne pathogen that affects sugarbeets but has not been a common problem in the region. These diseases attack the seed and/or germinating or recently emerged seedlings. Seedling diseases caused by these fungi produce similar symptoms often called damping off. Two or more pathogens may simultaneously or successively attack seedlings. Disease severity and prevalence varies among regions, between fields and within a field. Seedling disease severity is determined by the availability of disease inoculum, environmental factors and varietal susceptibility.

Aphanomyces cochlioides and Rhizoctonia solani are the primary fungi that cause root rots of economic concern. Phoma betae, several Fusarium species, Pythium aphanidermatum and Erwinia caratovora are of minor importance. Many of these fungi survive for long periods of time in the soil. Symptoms vary from minor lesions to complete destruction of the root by dry or wet rots. Control methods for severe root rot and seedling disease problems include varietal resistance, fumigation crop rotations,

Table 2. Effectiveness of herbicides on major weeds in sugarbeets.
  Grasses Broadleafs  
  Barn-yard grass Fox-tails
(pigeon grass)
Wild oats Can-ada this-tle Cockle-bur Com-mon Lambs-quar-ters Eastern black night-shade Ko-chia Pig-weed, red-root Russ-ian this-tle Sun-flower, volun-teer Wild buck-wheat Wild mus-tard Herbicide persistence after 12 months
Preemergence or Preplant Incorporated
cycycloate
(Ro-Neet)
G G F/G N P F/G F/G P F/G P N F/P P N
diethatyl (Antor) F/G F/G F/G P P P F/G P G P P P P N
EPTC (Eptan) G G F/G N P F F/G F F/G P N F P N
ethofumesate (Norton) P F/G F/G N P P/F F/G F/G G F/G P F/G F O
pyrazon (Pyramin) P P P P P/F G G P/F G P/F P P/F G N
Postemergence
clopyralid (Stinger) P N N G G P/F F/G N P P/F G F/G P S
desmedipham (Betanex) P P N N P/F G G P/G G P P F G N
desmedipham + phenmedipham (Betamix) P F N N F G G F F/G P P F/G G N
endothall (Herbicide 273) N N N N P/F P - P P/F P F/G F/G F N
ethofumesate + desmedipham (Nortron + Betanex) F F/G P N F/G G G F/G G P/F P G G N
ethofumesate + desmedipham + phenmedipham (Norton + Betamix) F F P N F G G F G P/F P F/G G N
sethoxydim (Proast) G G G N N N N N N N N N N N
trifluralin (Layby) G G F N N G N G G N N F N O
G=Good; F=Fair; P=Poor; N=None; O=Often; S=Seldom; -=No data.

seed treatments and fungicide application. Control of root rots is often expensive and temporary in nature. Commercial sugarbeet seed is usually pretreated with one or more protectant fungicides.

Cercospora leafspot caused by the fungus Cercospora beticola is the most serious foliar disease of sugarbeets in the north central United States. Losses of 30 % or greater recoverable sucrose per acre are fairly common under moderate to severe disease conditions. Also, roots of affected plants do not keep well in storage piles either. Many of the currently grown high yielding varieties are susceptible or moderately susceptible to Cercospora. Warm days and nights with high humidity or free water on the crop canopy are most conducive to serious disease outbreaks.

A Cercospora leafspot disease prediction model is available to monitor disease development and plan a fungicide control program. Crop rotation is an important control measure since the disease overwinters on infected beet leaves. A three year rotation is minimal for reducing disease inoculum. Burying beet refuse by tillage helps reduce inoculum survival and dispersal. Varieties vary greatly in Cercospora resistance. The disease develops slowly and is a minor problem on some varieties but can cause total defoliation of others. Triphenyl tin hydroxide fungicides give best Cercospora leaf spot control. Mancozeb and copper fungicides give acceptable Cercospora control especially with less severe disease outbreaks.

Powdery mildew, caused by the fungus Erysiphe betae, is the only other serious foliar disease of sugarbeets in the region. The disease is favored by long periods of drought, warm days cool nights and a wide fluctuation in day-night temperatures. Control of powdery mildew with sulfur fungicides is relatively inexpensive and usually very successful. Bayleton also is registered for powdery mildew control, but at rates that make control much more expensive than with sulfur. Crop rotation is not an effective control measure. Little data is available on varietal resistance or tolerance to the disease.

Other foliar diseases that occur in the region are of little if any economic importance. They include Ramularia, Alternaria and Phoma leaf spots. Virus diseases like Western Yellows, Curly Top and others are absent or of no economic importance.

J. Insects and Their Control

The sugarbeet root maggot, Tetanops myopaeformis is the most serious insect of sugarbeets in the region. It is present in all areas of the Red River Valley of Minnesota and North Dakota. Infestations are particularly severe on lighter textured soils. Damage is caused by the larval stage of the life cycle of the insect. Crop damage is caused by feeding on the plant root system. Stand loss may be severe if heavy infestations occur in the seedling stage. Plants surviving feeding damage may yield up to 50% less than undamaged fields. Sugarbeet root maggot control generally is good to excellent when granular soil insecticides are applied at planting time. Crop rotation and resistant varieties are not acceptable control alternatives.

Several species of cutworms are the second most important insect problem. Severe stand loss can occur when heavy infestation of cutworms go undetected in fields. Grasshoppers have caused serious stand loss in droughty years in particular. Several species hatch from late May through June. Heavy infestations of later instar stage grasshoppers can rapidly cause sugarbeet stand loss in a field.

Flea beetles, wireworms, root aphids, white grubs and beet webworms are less common sugarbeet pests. However, severe localized infestations of these pests occur. White grubs and wireworm may cause serious stand loss to germinating and emerging beet seedlings. Flea beetles occasionally cause some stand loss if insect populations are high. Root aphids may cause severe yield loss in dry years, especially when cracks form in the soil providing ready access to secondary plant roots the insects feed on. Sugarbeet webworm outbreaks are very infrequent in the region. Leaf feeding may occasionally justify insecticide treatment.

Wireworms, cutworms and white grubs may be controlled by certain soil applied sugarbeet root maggot insecticides. Check product labels for specific recommendations. Severe cutworm outbreaks usually require a postemergence insecticide application for successful control. Flea beetles and webworms can be successfully controlled with foliar insecticide. No acceptable control measures are available for the root aphid. Crop rotation does not give effective control for any of these insects. The key to a successful insect control program in sugarbeets is timely monitoring of insect populations, followed by recommended insecticide applications when insect populations and crop damage justify pesticide use.

K. Harvesting and Storage:

Sugarbeets are harvested in late September and October. A mechanical defoliator is used to remove all the foliage from the beet root prior to lifting. Removal of all foliage is essential to prevent leaf regrowth in storage piles. Heavy frosts prior to defoliation make proper foliage removal from the beets more difficult. Immediately following defoliation, sugarbeet lifter-loader harvesters pull beets from the soil and load them on trucks. The harvesters remove most of the soil from the beets prior to loading. Wet soil conditions greatly slow the harvesting operations and result in higher amounts of dirt clinging to the beets. After the trucks are loaded, the sugarbeets are delivered to piling stations or the factory for storage and processing. Sugarbeet harvesting requires at least two specialized expensive pieces of equipment, the defoliator and the harvester, plus trucks that may be used very little except at sugarbeet harvest.

Storage is primarily on flat unpaved piling grounds provided by the processing company in the factory yard or at outside piling stations. Some storage also may be over forced air ventilation/aeration systems or in climate controlled storage buildings. These specialized piling grounds or buildings minimize the loss of sugar caused by storage rots and root respiration.

VI. Yield Potential:

Sugarbeet yields in Minnesota and North Dakota usually average from 13 to 25 tons/acre under dryland conditions depending on the climate. Less than 1% of the present acreage in Minnesota and North Dakota is irrigated. Yields under irrigation may be 15 to 30% greater. Other crops in rotation often yield less following sugarbeets because of soil water depletion by the sugarbeet crop.

Sugarbeet production requires much more management attention than small grain, soybean, or corn production. Specialized equipment is required for sugarbeets that can not be used for other crops in rotation.

VII. Economics of Production and Markets:

Market access may be the greatest obstacle facing farmers who want to begin sugarbeet production in North Dakota, Minnesota or Wisconsin. All present processing facilities are operating at full capacity as farmer- owned cooperatives. If increased acreage becomes available at these factories, the present grower owners have first opportunity to grow these sugarbeets. A new grower must purchase an existing contract or shares owned in the cooperative by a present sugarbeet grower in order to market sugarbeets.

No new processing facilities have been built in the United States since 1975. Estimated cost to build an average size processing facility today is $100 million.

Average economic returns from sugarbeets in the region have been greater than for small grains, corn, dry edible beans and soybeans. Prices paid for sugarbeets also have been more stable than for most other crops. While return per acre from sugarbeets may be good, risk of economic loss is also greater than with most other crops. Average total cost of production in Minnesota and North Dakota in 1989 was from $492 to $557 per acre. Cost of production for a new grower starting sugarbeet production would probably exceed $600 per acre.

No one should attempt to initiate sugarbeet production on their farm without securing a market for his crop and completing an economic feasibility study.

VIII. Information Sources:

- Sugarbeet Research and Extension Reports. Volume 1 to 20. North Dakota State University and University of Minnesota Extension Services.

- Sugarbeet Production Guide. 1990 and 1991. North Dakota State University and University of Minnesota Extension Services.

- Sugarbeet Insects. Nov. 1988. North Dakota State University Extension Service, Fargo, ND.

- Insects Affecting Sugarbeets in North Dakota. Circular E-695. North Dakota State University Extension Service.

- Sugarbeet Diseases of the North Central United States. NCR Extension Publication #140, Feb. 1981. North Dakota State University and University of Minnesota Extension Services.

- Cercospora Leafspot of Sugarbeets. Revised Oct. 1987. North Dakota State University Extension Service. PP-764.

- Sugarbeet Powdery Mildew. Dec. 1988. North Dakota State University Extension Service. PP-967.

- Seedling and Root Rot Diseases of Sugarbeets. 1989. Ag-FO-3702. University of Minnesota Extension Service.

- Fertilizing Sugarbeets. Sept. 1988. SF-714 Revised. North Dakota State University Extension Service.

- Compendium of Beet Diseases and Insects. American Phytopathological Society Series. St. Paul, MN.

- Pests, Diseases and Disorders of the Sugarbeet. The Beet Sugar Development Foundation. Denver, CO.

References to pesticide products in this publication are for your convenience and are not an endorsement of one product over other similar products. You are responsible for using pesticides according to the manufacturer's current label directions. follow directions exactly to protect people and the environment from pesticide exposure. Failure to do so violates the law.


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