Pest Management Guidelines - Vegetables
Pest Management Guidelines
A Cornell Cooperative Extension Publication

  
Cornell Guide for Pest Management of Vegetables

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Chapter 12 Asparagus

Chapter 14  Beets


Contents

14.1 Recommended Varieties. 97

14.2 Planting Methods. 97

14.3 Fertility. 97

14.4 Harvesting. 97

14.5 Disease Management 98

14.5.1 Leaf spots, caused primarily by Cercospora beticola but also by Phoma batae  98

14.5.2 Pocket rot.  This disease is caused by Rhizoctonia solani and its sexual stage Thanatephorus cucumeris. 99

14.5.3 Seed rot, damping-off, and root rot. This disease complex is primarily caused by Pythium ultimum and Rhizoctonia solani,  however  Aphanomyces cochlioides and Phoma betae also occur on beets  99

14.5.4 Sugar beet cyst nematode, Heterodera schachtii 99

14.6 Insect Management 101

14.6.1 Spinach leafminer, Pegomya hyoscyami 101

14.7 Weed Management 101

 

 

14.1 Recommended Varieties

 

Detroit Dark Red

Red Ace

Ruby Queen

Crosby (greens or roots)

14.2 Planting Methods

 

The beet is a cool-season, root vegetable that tolerates frosts and mild freezes. Seed germinates at soil temperatures between 40° and 90°F, optimally 50° to 85°F. Because beet plants withstand cool growing conditions and the seed germinates at soil temperatures below 50°F, planting can begin in late April. The best root quality and color are obtained when the crop matures during cool temperatures and bright sunlight. When grown under warm conditions, root color is lighter, sugar content is lower, and color zoning in roots is more pronounced than under cool conditions.

 

Beets are biennial, normally producing an enlarged root the first growing season and, after a cold induction period, a seedstalk. Premature seedstalk initiation can occur if the plants are subjected to two to three weeks of temperatures below 45°F after they have several true leaves. Plants of some varieties initiate premature seedstalks more readily than others; many of the newer varieties are less sensitive to this problem.

 

Well-drained, sandy loam to silt loam soil is preferred for best growth and quality. Beets can also be grown on muck soil, but weed control is difficult. A soil with good structure is highly recommended because beets respond favorably to aeration.

 

A beet seedball normally contains from two to four viable seeds, and more plants than seedballs may result, especially if conditions are favorable for germination. Larger seedballs contain more seeds than do smaller seedballs. Desired plant spacing is obtained by adjusting seeding rate. Plants are sometimes thinned for the fresh market. See Table 14.2.1 Recommended spacing

                                                                                     

Table 14.2.1 Recommended spacing.

 

Type

Row

(in inches)

In-row seeding rate1 (in pounds per acre)

Fresh-market

16-24

8-10

Processing

16-24

15-25

1: The lower rate of seed is sown early so the roots will size quickly for early harvest

 

14.3 Fertility

Use lime to maintain a pH of 6.5 to 6.8 in all parts of the field. Beets are especially sensitive to low pH and should not be planted in soil with a pH below 6.0. Because beets use boron inefficiently, this element must be applied to most soils in New York. A boron deficiency causes plant foliage to be stunted and distorted, and roots exhibit symptoms of internal breakdown. Boron is less available in high pH soils. Apply 2 1/2 to 5 pounds of boron per acre mixed with fertilizer. Use the lower rate if nutrients have been applied two to three times in the previous five years. Boron is toxic to many plants and care must be taken when developing a rotation plan. Beans, peas, and cucurbits are especially sensitive to boron residues. See Table 14.3.1 for the recommended rates of nitrogen, phophorus, and potassium.

14.4 Harvesting

For fresh market, the crop is usually ready for harvest in 60 to 85 days. The processing crop is harvested in 90 to 110 days, but a thick plant stand can be held in the field for a relatively long time. Processing beets are usually harvested until mid-November. Yields for the fresh market range from eight to 12 tons per acre and approximately 15 to 20 tons per acre for processing.

 

Machine harvesters are used for the processing crop and for the market crop that is sold topped. Beets for bunching are handpicked and tied. Topped beets can be stored for several months at temperatures near 32°F and 95 to 98 percent relative humidity.


 

Table 14.3.1 Recommended application rate of nutrients based on soil tests.1,2

N (pounds/acre)

P2O5 (pounds/acre)

 

K2O (pounds/acre)

Comments

 

Soil Phosphorus Level

 

Soil Potassium Level

 

 

low

med.

high

 

low

med.

high

 

150-175

150

100

50

 

300

200

100

Total recommended

 

 

 

 

 

 

 

 

 

25-50

75

25

0

 

225

150

50

Broadcast and disk-in.

25

75

75

50

 

75

75

50

Band place with planter.

50

0

0

0

 

0

0

0

Apply three weeks after planting

50

0

0

0

 

0

0

0

Apply eight weeks after planting

 



14.5 Disease Management

14.5.1 Leaf spots, caused primarily by Cercospora beticola but also by Phoma batae

Time for concern: Most prevalent in mid to late season with daytime temperatures of 75° to 80°F and with frequent rainfall or long periods of 90 to 100 percent relative humidity.

 

Key characteristics: Cercospora leaf spot appears as small, circular lesions that are light tan to brown with a distinct dark brown to purple halo.  Phoma leaf spot appears as lesions of various size with concentric ring pattern and fruiting bodies of the pathogen.  When lesions of both pathogens mature, the centers become gray and brittle and fall out.

Management Option

Recommendation

 

Scouting/thresholds

Record the occurrence and severity of leaf spot. No thresholds have been established.

 

Resistant varieties

No resistant varieties are currently available.

 

Crop rotation

Minimum two year rotation out of beets with nonhost crops preferably grains.

 

Site selection

Avoid fields with tree lines and stagnant air circulation, as long duration of  leaf-wetness is conducive for disease development.  Also, weeds belonging to the family Chenopodiaceae may serve as a source of inoculum.

 

Fertility

Use nitrogen to promote growth and development of new leaves which are less susceptible to both pathogens and will aid in harvesting.

 

Seed selection/treatment

Plant commercially treated seed to prevent seed decay and reduce seedborne inoculum.

 

Postharvest

If possible, crop debris should be destroyed as soon as possible to remove this source of disease for other plantings and to initiate decomposition.

 

Sanitation

This is not a currently viable management option.

 

Compound(s)

 

 

 

 

 

Common name

Rate/A

PHI

REI

Field

 

 

Trade name

Product

(days)

(hours)

Use EIQ

Comments

azoxystrobin

 

 

 

 

 

 

Quadris F

6.2-15.4      fl oz

0

4

1.3-3.4

Do not apply more than 2 sequential foliar applications of these products or other strobilurin (Group 11) before alternating with a fungicide that has a different mode of action.  Do not spray these products where spray drift may reach apple trees or use same sprayer to apply sprays to apple trees.

 

Amistar 80 WDG

2-5  oz

0

4

1.5-4.6

copper compounds

 

 

 

 

 

 

Champ F or OLF

1 1/3 –

2 2/3 pt 

0

24

19-38

 

Begin spraying after disease detection.  Label varies with manufacturer and formulation. Addition of a suitable agricultural spray oil is recommended.

pyraclostrobin

 

 

 

 

 

 

Cabrio EG

8-12 oz

0

12

3-5

No aerial application in NYS.  Do not make more than 2 sequential applications before alternating to a non-strobilurin (Group 11) fungicide with a different mode of action.

 


14.5.2 Pocket rot.  This disease is caused by Rhizoctonia solani and its sexual stage Thanatephorus cucumeris.

Time for concern: Planting through the end of the season, but long term planning is required for sustainable management.

 

Key characteristics: Pocket rot appears first as black cankers on the lower petioles and the crown area as well as dry, black-rotted portions of the fleshy beets. Lesions may also be found on leaves. With favorable conditions, infections progress from plant to plant, resulting in open areas of dead plants (pockets) of various length.  See references 6-8.

Management Option

Recommendation

 

Scouting/thresholds

Record the occurrence and severity of pocket rot. No thresholds have been established.

 

Resistant varieties

No resistant varieties are currently available. Under severe disease pressure, Ace exhibits lower disease levels.

 

Crop rotation

Rotate out of vegetables with nonhost crops such as grains. Rhizoctonia attacks most vegetables and has a very wide host range.

 

Site selection

Sites that are well-drained with healthy soil and good soil structure are preferred.

 

Seed selection/treatment

Plant vigorous, disease-free seed, and make sure it has been treated with Apron plus thiram and/or Maxim.

 

Cultivation

To reduce disease severity, minimize the amout of soil thrown on crown tissues during cultivation.

 

Postharvest

If possible, crop debris should be destroyed as soon as possible to remove this source of disease for other plantings and to initiate decomposition.

 

Sanitation

This is not currently a viable management option.

 

Compound(s)

 

 

 

 

 

Compound(s)
Common name

Rate/A

PHI

REI

Field

 

 

Trade name

Product

(days)

(hours)

Use EIQ

Comments

azoxystrobin

 

 

 

 

 

 

Quadris F

.4 - .8 fl oz/1000 row feet

0

4

<1-2

Make two applications at 14 day intervals with first application at second cultivation.   Do not spray these products where spray drift may reach apple trees or use same sprayer to apply sprays to apple trees.

 

Amistar 80 WDG

0.125-0.25 oz per 1000 row feet

0

4

<1

 

 

14.5.3 Seed rot, damping-off, and root rot. This disease complex is primarily caused by Pythium ultimum and Rhizoctonia solani,  however  Aphanomyces cochlioides and Phoma betae also occur on beets

Time for concern: Planting to early-midseason, but long term planning is required for sustainable management.

 

Key characteristics: Poor emergence, uneven growth, dead seedlings, wire-stem symptoms, and reddish discoloration of aboveground plant parts appear in patches and low spots. Infected plants develop abnormal, fleshy roots with constrictions and rotted areas of various shapes and sizes. See Reference 1.

Management Option

Recommendation

Scouting/thresholds

Record the occurrence and severity of seed and root rot diseases. No thresholds have been established.

Resistant varieties

No resistant varieties are currently available.

Crop rotation

Minimum two year rotation out of vegetables. Beans, cabbage, peas, carrots, onions or potatoes should not be considered as rotational crops as they will increase pathogen populations. Only rotation with grain crops is known to be effective.

Management Option

Recommendation

Site selection

Sites that are well-drained with healthy soil and good soil structure are preferred. Planting on raised ridges will also reduce root rot severity. Avoid soil compaction and crusting.

Seed selection/treatment

Plant seed treated with Apron plus Thiram and/or Maxim. The combination of Thiram plus Apron is effective during cool, wet weather when Pythium is a problem. Apron is highly effective against Pythium; Thiram provides protectant activity against a broad spectrum of fungi, but especially Phoma. Maxim and captan are also available as seed treatments in combination with Apron and Thiram.  Maxim has activity against Rhizoctonia, Fusarium and Phoma.

Postharvest

If possible, plow under infected crop debris to remove this source of disease for other plantings and to initiate decomposition.

Sanitation

Not a viable option.

Compound(s)

Ridomil, applied as a soil treatment for Pythium, is available.  Check label for details.

 

14.5.4 Sugar beet cyst nematode, Heterodera schachtii

 

Time for concern: Before and at planting

 

Key characteristics: Sugar beet cyst nematode eggs are enclosed in brown, leathery, lemon-shaped cysts, 1/40 inch in length. When first evident on the root surface, females are white or cream colored. The effected plants are stunted, wilt at midday, and produce small beets.

Management Option

Recommendation

 

Scouting/thresholds

For documentation of occurrence, begin scouting four to six weeks after planting. One sign that a field is infested is the presence of swollen, immature females attached to the surface of the roots of stunted plants. Dig roots carefully to prevent breaking roots and jarring loose the females. The first evidence of infestation aboveground is stunted growth in a small area of the field. Record the occurrence of sugar beet cyst nematodes. The threshold value is six to nine eggs per cubic centimeters (cc) of soil. Collect soil samples in the fall or a few weeks prior to planting for analysis. See Reference 2.

 

Resistant varieties

No resistant varieties are available.

 

Crop rotation

Minimum four year rotation with nonhost crops if soil is heavily infested. Plants in the Brassicaceae (crucifer) and Chenopodiaceae (spinach and lambsquarters) families are hosts to this nematode and should not be planted during this rotation time period. See Reference 3.

 

Postharvest

If possible, crop debris should be destroyed as soon as possible after harvest to stop further development of the pathogen on host roots and to initiate decomposition.

 

Sanitation

Clean equipment after use on an infested field.

 

Site selection and Seed selection/treatment

These are not currently viable management options but stress and damage to plants will be reduced in healthy soils.

 

Compound(s)

 

 

 

 

 

Common name

Rate/A

PHI

REI

Field

 

 

Trade name

Product

(days)

(hours)

Use EIQ

Comments

fenamiphos

 

 

 

 

 

 

*Nemacur 3                3 lb/gal

4-6 oz/1,000 ft row

90

48

6-9

Refer to label for dosages at specific band widths.

*Restricted use only.

 

 

 

 

 


14.6 Insect Management

14.6.1 Spinach leafminer, Pegomya hyoscyami

 

Time for concern: Emergence through harvest. Only a pest if infested leaves are to be harvested or if beets are to be sold in bunches.  Infestations do not reduce yield, and beets grown for their roots do not need treatment.

 

Key characteristics: Adult flies are gray with yellow legs. Adults emerge in late May and early June and lay small clusters of eggs on the undersides of leaves. Newly hatched larvae bore into the leaves producing characteristic slender, winding mines and blister-like blotches.

Management Option

Recommendation

 

Scouting/thresholds

Scout for eggs on the lower surface of the leaf.  If treatments are needed, make sure that the lower leaf surfaces are covered. Use air blast or high pressure, high volume rigs.

 

Natural enemies

Natural enemies help control the spinach leafminer populations. Use Reference 4 or www.nysaes.cornell.edu/ent/biocontrol/ for identification of natural enemies.

 

Note(s)

Destruction of weed hosts can help reduce the risk of infestation. The use of protective crop screens or covers can prevent infestations.

 

Resistant varieties

No resistant varieties are available.

 

Crop rotation

Because leafminers overwinter in the soil, avoiding fields planted to beets the previous year may help reduce infestations.

 

Site selection, Post-harvest, and Sanitation

These are not currently viable management options.

 

Compound(s)

 

 

 

 

 

Common name

Rate/A

PHI

REI

Field

 

 

Trade name

Product

(days)

(hours)

Use EIQ

Comments

diazinon

 

 

 

 

 

 

*Diazinon 50W  0.5 lb/lb

0.5-1 lb

14

24

11-22

 

spinosad

 

 

 

 

 

 

SpinTor 2SC               2 lb/gal

4.5-6 fl oz

3

4

1-2

Do not apply more than 21 oz per crop per season.

 

Entrust                 

0.8 lb/lb

2-3 oz

3

4

2-3

Do not apply more than 6.5 oz per crop per season.

*Restricted use only.

 

 

 

 

 

 

14.7 Weed Management

Key characteristics: Weed fact sheets provide a good color reference for common weed identification. See Reference 5.  See Chapter 4 for information on scouting/thresholds, site selection, cultivation, and banding of herbicides.

Compound(s)

 

 

 

 

 

Common name

Rate/A

PHI

REI

Field

 

 

Trade name

Product

(days)

(hours)

Use EIQ

Comments

preplant incorporated

cycloate (annual grasses and broadleaves except galinsoga, ragweed and mustard)

 

Ro-Neet 6-E                6 lb/gal

2-2.67 qt

 

12

45-60

Use the lower rate with hot, dry, soil conditions. When possible, apply 7-10 days ahead of planting and incorporate immediately. Reworking the soil at planting often improves weed control and reduces the chance of crop stunting.

Compound(s)

 

 

 

 

 

Common name

Rate/A

PHI

REI

Field

 

 

Trade name

Product

(days)

(hours)

Use EIQ

Comments

preemergence

s-metolachlor (annual grasses, yellow nutsedge, galinsoga, nightshade species, and  selected broadleaves)

 

*†Dual Magnum 7.62EC

7.62 lb/gal

0.67 pt

24

 

12

Not for use in Nassau/Suffolk Counties.   See comments below.

Make a single application after planting, before the crop or weeds emerge.  This may be made as either a broadcast or banded application.  Do not use on soils having less than 1.5% or greater than 10% organic matter. Syngenta has created a new means of acquiring the indemnification required when using Dual Magnum on the vegetable crops registered on New York State’s multi-crop 24(c) Special Local Need (SLN) supplemental label.  The required product label and indemnification can only be obtained through the “special labels” link found at www.farmassist.com and must be obtained by the ‘end-user’.  If difficulties are encountered in using the website call the Syngenta Customer Resource Center at 866-796-4368.

preemergence or postemergence

pyrazon (annual broadleaves)

 

 

Pyramin 50 DF                      4.51 SC

4.6-5.4 lb             5.5-6.5 pt

 

12

12

 37-43

 44-52

Effective with rain. Apply at time of seeding. A postemergence (emergency or salvage) treatment may also be used if soil applied preemergence herbicides have failed or were missed. Timing of the postemergence treatment is critical. Beets must have at least 2 expanded true leaves and weeds should have fewer than 2-4 true leaves. Larger weeds will not be controlled.

postemergence

clethodim (annual and perennial grasses)

 

 

*Select 2EC                   2 lb/gal

6 - 8 fl. oz.

30

24

2

For control of numerous annual and perennial grasses.  Apply when grasses are 2-6 inches tall and actively growing.  DO NOT apply more than 32 fl. oz. of Select 2EC (0.5 lb ai)/A/season.  Application on LONG ISLAND is restricted to no more than 16 fl. oz. of Select 2EC (0.25 lb ai)/A/season.  Always use a crop oil concentrate at 1% V/V in the finished spray volume.

clopyralid (ragweed, hairy galinsoga, smartweed, wild buckwheat, dandelion, hairy nightshade, Canada thistle)

 

†*Stinger 3EC                 3 lb/gal 

0.5 pt

30

12

4

Not for use in Nassau/Suffolk Counties.  Make 1 broadcast application per crop per year.  Stinger may be tank-mixed with other herbicides labeled for use on garden (red) beets.

phenmedipham (annual broadleaves and grasses, except pigweed)

 

 

Spin-Aid                      1.3 lb/gal

1.5-6 pt

 

24

7-29

Apply when weeds have fewer than 2 true leaves.  Spin-Aid effectively suppresses several broadleaf weeds common in beet fields.  Common lambsquarters and common chickweed are particularly sensitive.  Three low rate applications of Spin-Aid applied at approximately 2 wk intervals, beginning when the beets are in the cotyledon to 2-true leaf stage have proved to be very effective in research trials.  Under adverse weather conditions slight and usually transient injury has been observed.  Read and observe cautionary statements/restrictions found on the product label.


 

Compound(s)

 

 

 

 

 

Common name

Rate/A

PHI

REI

Field

 

 

Trade name

Product

(days)

(hours)

Use EIQ

Comments

postemergence - hooded row middle application

carfentrazone

 

 

Aim EW                     1.9 lb/gal

0.5-2.0        fl oz/ application

0

12

<1

May be used only as a hooded, row middle application.  Sprayers must be designed to prevent ANY contact with the crop and may not be operated at more than 5 MPH.  Special care must be taken when operating on uneven ground.  See product label for additional precautions.

*Restricted use only.

(†) Not for use in Nassau/Suffolk Counties

 

 

 

 

 

 

 

 

 

 

 

 

 

14.8 References

 

1      Abawi, G. S., D. C. Crosier, A. C. Cobb, and R. F. Becker. 1986. Root rot of table beets in New York State, New York’s Food and Life Sciences Bulletin 115. 8 pp.

2      Abawi, G. S., and W. F. Mai. 1980. Effects of intial population densities of Heterodera schachtii on yield of cabbage and table beets in New York State. Ecology and Epidemiology 70: 481-485.

3      Mai, W. F., and G. S. Abawi. 1980. Influence of crop rotation on spread and density of Heterodera schachtii on a commercial vegetable farm in New York. Plant Disease 64: 302-305.

4      Hoffmann, M. P., and A. C. Frodsham. 1993. Natural Enemies of Vegetable Insect Pests. Cornell Cooperative Extension. 64 pp.

5      Pennsylvania State University. 1987. Weed identification, pp. 1-32. Pennsylvania State University Cooperative Extension, University Park.

6      Olaya, G. and G.S. Abawi.  1994.  Characteristics of Rhizoctonia solani and binucleate Rhizoctonia species causing foliar blight and root rot on table beets in New York state. Plant Disease 78: 800-804.

7      Olaya, G. and G.S. Abawi.  1994. Influence of inoculum type and moisture on development of Rhizoctonia solani on foliage of table beets.  Plant Disease 78: 805-810.

8      Olaya, G., G.S. Abawi, and J. Barnard.  1994.  Response of Rhizoctonia solani and binucleate Rhizoctonia to five fungicides and control of pocket rot of table beets with foliar sprays.  Plant Disease 78: 1033-1037.

 


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