Chapter 16 Carrots
Link to IPM Elements for Carrots
Link to New York Carrot Crop Profile
Link to Resource
Guide for Organic Insect and Disease Management
Link to Cornell Organic Guide for processing carrots
Long, slender Imperator-type varieties are desired for fresh market. Blunt-tipped Nantes varieties are preferred for sliced, processed products, and blocky Chantenay or Danvers types are used for dicing. Varieties that have done well in trials include Bolero, Magnum, Red core Chantenay, Ya Ya and Danvers. Cultivars vary in susceptibility to aster yellows. See Reference 1.
Table of carrot disease resistant varieties
Carrots are a cool-season crop that can tolerate light frosts. Good quality roots (judged by length, shape, and color) develop when soil temperature is between 60° and 70°F. At warmer temperatures, the roots will be shorter, and internally the color will be lighter orange.
Carrots are biennial, normally producing an enlarged root the first growing season and, after a prolonged cold period (below 45°F), a seedstalk (assuming that the roots are not allowed to freeze). When spring conditions are especially cool, bolting or premature seedstalk development can occur during the first growing season. If this happens, the root will be woody and inedible. Because large seedlings are more susceptible to bolting than are smaller seedlings, premature seedstalk development is generally associated with early spring plantings. Varieties differ greatly in their susceptibility to bolting.
The length of carrot roots is determined within the first few weeks after germination because the taproot quickly penetrates deep into the soil. If the young taproot is injured, it will become branched and forked, making the root unmarketable. Excessive soil moisture, insects, diseases, nematodes, and soil compaction can all markedly affect root quality. Wet soil near harvest will cause the roots to become rough and promote root rot diseases.
Obtaining long, straight, smooth roots is difficult. Light-textured soils that contain few stones or well-drained muck soils are preferred. Primary tillage should be fairly deep, but care must be taken not to impair soil structure by working the soil when wet. Use of raised beds, which tend to increase drainage, aeration, and total depth of tilled soil, can improve the length and shape of roots.
Some carrot varieties (Nantes and related types) are especially susceptible to the formation of chlorophyll (green pigment) on the shoulders and within the core area of the root. To reduce this problem, the soil should be hilled over the shoulders of the roots at the last cultivation.
|
|
|||
| Table 16.2.1 Recommended spacing. | |||
|
|
|||
| Type |
Row
(inches) |
In-row
(3 lines at) |
Seed
(lb/acre) |
|
Imperator or Nantes |
18-36
|
1.5"
|
2
to 3
|
| Chantenay or Danvers |
18-36
|
1.5"
|
1
to 2
|
Crop rotation and disease management article
Maintain a pH of 6.0 to 6.5 on mineral soils; consider liming when the pH falls below 5.2 on muck soils. See Table 16.3.1 for the recommended rates of nitrogen, phosphorus, and potassium.
Cornell cover crop decision tool
Go to Cornell Nutrient Analysis Lab website to find out how to get soil samples tested.
See Cornell Soil Health website and manual
Cornell article: "Closing the phosphorus cycle on vegetable farms: releasing soil-bound phosphorus to support springtime seedling growth."
SARE Publication: "Building Soils for Better Crops"
SARE publication: "Managing Cover Crops Profitably"
Machine harvesters are used for the processing crop and for roots that are marketed in polyethylene bags. Bunching carrots are hand harvested and tied together.
Carrots can be stored for several months at 32°F and 90 to 95 percent relative humidity. If the temperature is allowed to rise, sprouting will occur. If the relative humidity is too low, the roots will desiccate.
See Cornell GAPsNET
See Cornell "Smart Marketing" series
See USDA grade standards for bunched carrots, topped carrots, short trimmed topped carrots, and processed carrots
See USDA Agricultural Marketing Service site
See current wholesale prices from US markets
See UC
Davis post harvest guide for carrots
SARE Publication: "Marketing Strategies for Farmers and Ranchers"
SARE Publication: "Direct Marketing Resource Guide"
| Aster yellows
| Cavity spot | Rhizoctonia
crown rot |
| Alternaria leaf blight | Northern
root_knot nematode |
| Sclerotinia white mold | Seed
decay | Storage rots |
SARE Publication: "A Whole-Farm Approach to Managing Pests"
Ontario Canada fact sheet on aster leafhopper/aster yellows
Time of concern: June through August
Key characteristics: The severity of aster yellows and damage
to the crop depends on the age of the crop when the infection occurs.
The first symptom observed in the field is leaf yellowing. In severely
affected plants, the new shoots from the crown are sickly and have a
"witch's broom" appearance. Older leaves become red and are
easily recognizable in the field. The petioles become twisted and are
easily broken-off making mechanical harvesting and bunching difficult.
Roots of infected plants exhibit numerous tufts of fine roots (hairy
condition).
For management options, see the Aster leafhopper.
Ontario Canada fact sheet on carrot root diseases
Time for concern: Planting through end of the season
Key characteristics: Elliptical- to irregular-shaped
depressed lesions appear across the tap roots. Initially lesions are usually
less than 1 1/2 inches in diameter at different stages of decay. Symptoms
may not be apparent until carrots are approaching marketable size.
| Management Option | Recommendation |
| Scouting/thresholds | Record the occurrence and severity of cavity spot. No thresholds have been established. |
| Resistant varieties | Carrot varieties differ widely in their susceptibility to cavity spot, but varieties reported to perform better include Six Pak, Six Pak II, 24 Karat, and Dagger 78. Table of carrot disease resistant varieties |
| Crop rotation | Minimum three year rotation out of vegetables and alfalfa. Crop rotation and disease management article Cornell cover crop decision tool Cornell article: "Cropping sequences and root health" Cornell Forage Species Selection Tool |
| Site selection | Select fields
with well drained , light textured, and healthy soils.
SARE Publication: "Building Soils for Better Crops" SARE publication: "Managing Cover Crops Profitably" |
| Seed selection/treatment | Plant vigorous, disease-free seed that has been treated with fungicides (Apron and Maxim). |
| Harvest | Harvest carrots soon after they reach maturity because older carrots are more susceptible to this disease. |
| Postharvest and Sanitation | These are not currently viable management options. |
|
Compound(s) |
|||||
Cornell article: "General guidelines for managing fungicide resistance" |
|||||
Comparing Environmental Risks of Pesticides |
|||||
| Common name Trade Name |
Rate/A Product |
PHI (days) |
REI (hours) |
Field Use EIQ |
Comments |
| cyazofamid | |||||
6 fl oz |
14 |
12 |
2.0 |
Alternate sprays of Ranman (Group 21) with an effective fungicide with a different mode of action. . | |
| fenamidone | |||||
8.2 fl oz |
14 |
12 |
4.2 |
Apply only in a 1:1 alternation with a mefenoxam-containing fungicide like Ridomil Gold SL. | |
| mefanoxam | |||||
0.5-1.3 pt |
- |
0 |
4.3-11.2 |
A Group 4 fungicide. Preplant incorporated (broadcast or band): Apply in water or liquid fertilizer and mechanically incorporate in the top 2 inches of soil. Soil spray (broadcast or band): Apply in water or liquid fertilizer at planting or prior to emergence. A 7-inch band is recommended. |
|
| mefanoxam | |||||
|
0.25-1.0 pt |
7 |
48 |
2.2-8.7 |
For post planting applications: All ground applications must be followed by irrigation of 1 inch of water to promote movement of product into the root zone. See label. For directed spray (broadcast or band): Apply as a spray at base of plant. For banded application use a 7-inch band. See label. |
|
* Restricted use only † Not for use in Nassau/Suffolk Counties
Ontario Canada fact sheet on carrot root diseases
Time for concern: Planting through the end of the season
Key characteristics: Crown rot - symptoms
result from infections of R. solani AG-2 on the main root, often where
lateral roots emerge. Under favorable conditions, lesions of initial infections
continue to enlarge and develop into brown to black sunken lesions. The
canker/rotted areas remain dry unless colonized and softened by other
soil organisms. The lesions may penetrate several millimeters into the
tap root; this distinguishes crown rot from the cavity spot lesions caused
by Pythium species which are much shallower. Foliar blight
- symptoms first appear on tissues of the petioles or the crown areas.
A thin, brown layer of mycelial growth (hymenial layer) becomes visible
on the surface of petioles or crown areas. Small spores are produced on
these layers and may be carried away by splashing rain or winds and infect
adjoining plants. Typical cankers may also appear on the infected areas,
and severely infected plants may die resulting in open spaces. Crater rot of carrot is caused by another species of Rhizoctonia, R. carotae.
| Management Option | Recommendation |
| Scouting/thresholds | Record the occurrence and severity of crown and foliar blight diseases. No thresholds have been established. |
| Resistant varieties | No resistant varieties are available. |
| Crop rotation | Rotate out of vegetables, preferably with grain crops.Crop rotation and disease management article Cornell cover crop decision tool Cornell article: "Cropping sequences and root health" Cornell Forage Species Selection Tool |
| Plant density | Heavy plant density and narrow row spacing of carrots will increase the severity of these diseases, especially under moist conditions. |
| Hilling | Excessive hilling of carrots, under moist conditions, will increase disease occurrence. |
| Fungicide use | Applications with thorough coverage of the lower petiole and crown area effectively control foliar blight disease, if applied before infections occur (prior to hilling). |
| Seed selection/treatment | Plant vigorous, disease-free seed that have been treated with fungicides. |
| Postharvest | If possible, plow crop debris immediately after harvest to remove this source of inoculum for other plantings and to initiate decomposition. |
| Site selection | Select well drained sites with light textured and healthy soils. Planting on raised ridges will also be helpful. SARE Publication: "Building Soils for Better Crops" SARE publication: "Managing Cover Crops Profitably" |
| Sanitation | These are not currently viable management options. |
| Compound(s) | Quadris, Cabrio, Rovral and Serenade Soil are effective against Rhizoctonia. |
|
16.5.4 Alternaria
leaf blight, Alternaria dauci;
Cercospora leaf blight, Cercospora carotae; and Bacterial leaf blight, Xanthomonas campestris pv. carotae |
See Cornell Fact Sheet for Carrot Leaf Blights 1988
Cornell Carrot leaf blight fact sheet 2004
Carrot disease fact sheet from Ontario, Canada
Time for concern: See individual
pathogens listed below.
Key characteristics: These pathogens can
cause severe blight on carrot leaves and petioles during a prolonged
period of cool, wet and warm weather.
All three pathogens can be seedborne.Alternaria - dark brown
to black irregular spots first appear at the margin of the leaflets.
Lesions on the petioles and stems are dark brown and girdle the stems.
As the disease progresses, entire leaflets may shrivel and die. Lesions
are more prevalent on older foliage. Because cool weather is favorable
for development, Alternaria is most severe in late August and September.
Cercospora - small, circular, tan or gray spots with a dead center
first appear along the margins of the leaves causing the leaves to curl.
As the lesions increase in number and size, the entire leaflet dies.
The fungus attacks younger plants. Because it develops rapidly in hot
or humid weather, it is likely to occur in July and early August. Bacterial
- small yellow areas appear on the leaflets. The centers of the lesions
become brown and dry and are often surrounded by a yellow halo. See
Reference 2.
| Management Option | Recommendation |
| Scouting/thresholds | Record the type of leaf blight and severity of infection. When 25% of leaves are infected with Alternaria and Cercospora, make the first fungicide application. No threshold has been established for bacterial blights. Once detected spray program should commence, See Cornell report on combining scouting and tolerant cultivars for controlling leaf blight |
| Resistant varieties | Great differences exist in the tolerance of carrot varieties, thus scouting for disease threshold must be done by variety. Contact your Cornell Cooperative Extension office for details. Table of carrot disease resistant varieties See Cornell report on combining scouting and tolerant cultivars for controlling leaf blight |
| Crop rotation | Minimum two- to three-year rotation out of carrots is effective against the three diseases. Crop rotation and disease management article Cornell cover crop decision tool Cornell Forage Species Selection Tool |
| Soil maintentance | Well-fertilized soil reduces the development of Alternaria. A nitrogen application made in mid-August or early September may promote foliage development. An alternative method of applying nitrogen is to add sprayable urea to each fungicide spray. SARE Publication: "Building Soils for Better Crops" SARE publication: "Managing Cover Crops Profitably" |
| Seed selection/treatment | Plant only disease-freeand treated seed. All three pathogens can be seedborne. Hot water treatment of seeds reduces bacterial leaf blight. |
| Postharvest | 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) |
|||||
Cornell article: "General guidelines for managing fungicide resistance" |
|||||
Comparing Environmental Risks of Pesticides |
|||||
| Common name Trade Name |
Rate/A Product |
PHI (days) |
REI (hours) |
Field Use EIQ |
Comments |
| Alternaria leaf blight and others | |||||
| azoxystrobin | |||||
|
|
9.0-15.5 fl oz
|
0
|
4
|
3.5-6.0
|
For control of Alternaria and Cercospora leaf blights and has activity against Rhizoctonia foliar blight. Do not apply more than one application of Quadris before alternating with a fungicide that has a different mode of action (other than Group 11). Do not spray these products where spray drift may reach apple trees or use same sprayer to apply sprays to apple trees. |
| azoxystrobin+chlorothalonil | |||||
|
2-4
pt
|
0
|
12
|
44.3
|
For control of Alternaria and Cercospora leaf blights and has activity against Rhizoctonia foliar blight. Do not apply more than 2 sequential applications of Quadris before alternating with a fungicide that has a different mode of action (other than Group 11). Do not spray these products where spray drift may reach apple trees or use same sprayer to apply sprays to apple trees. | |
| azoxystrobin + propiconazole | |||||
14 fl oz |
14 |
12 |
4.9 |
Make no more than 1 application (Groups 11 + 3) before switching to a non-Group 11 fungicide. | |
14 fl oz |
14 |
12 |
8.1 |
||
| boscalid | |||||
| Endura WG | 4.5 oz |
0 |
12 |
5.2 |
For Alternaria leaf blight control. Do not make more than 2 sequential applications before alternating to a labeled fungicide with a different mode of action.(other than Group 7) |
| chlorothalonil | |||||
| Bravo Weather Stik or OLP 6 lb/gal |
1.33-2.0
pt
|
14
|
12
|
30.3-40.4
|
Note eye wash requirement for shortened reentry interval on label. Controls Alternaria and Cercospora leaf blights. |
| chlorothalonil + zinc | |||||
|
Bravo
Zn |
2.25-2.75
pt
|
0
|
12
|
32.4-39.6 + Zn
|
|
| copper compounds | |||||
|
Champ
|
1.33
lb
|
-
|
48
|
18.8
|
Label varies with manufacturer and formulation. Controls bacterial leaf blight. |
| cyprodinil + fludioxonil | |||||
| † Switch 62.5WG | 11-14 oz |
7 |
12 |
21.8-27.7 |
Begin applications for control of Alternaria leaf blight prior to or at the onset of disease. After 2 applications of †Switch 62.5 (a combination of Groups 9 and 12), alternate with another fungicide with a different mode of action for 2 applications. |
| iprodione | |||||
Rovral 4F |
1-2 pt 1 pt if tank-mixed with chlorothalonil |
0 |
24 |
10.1-20.1 |
Controls Alternaria leaf blight. and has activity against Rhizoctonia foliar blight (Group 2 fungicide). |
| propiconazole | |||||
|
4 fl oz solo 2 fl oz with chlorothalonil |
14 14 |
24 24 |
3.3 1.7 + chlorothalonil |
Both PropiMax and Tilt (Group 3) are labeled for Cercospora leaf blight and powdery mildew and for suppression of Alternaria leaf blight. Do not apply more than 16 fl oz/A/season. Follow most restrictive requirements when tank mixing with chlorothalonil. | |
|
4 fl oz solo 2 fl oz with chlorothalonil |
14 14 |
12 12 |
3.3 1.7 + chlorothalonil |
||
| pyraclostrobin | |||||
|
8-16
oz
|
0
|
12
|
2.7-4.1
|
Not for aerial application in NYS. Do not make more than 2 sequential applications of Cabrio (Group 11) or Pristine (Group 11 + Group 7) before alternating to a labeled fungicide with a different mode of action. Labeled for Alternaria and Cercospora leaf blight control. | |
| pyraclostrobin+boscalid | |||||
8-10.5 oz |
0 |
12 |
5.1-6.6 |
Not for aerial application in NYS. Do not make more than 2 sequential applications of Cabrio (Group 11) or Pristine (Group 11 + Group 7) before alternating to a labeled fungicide with a different mode of action. Labeled for Alternaria and Cercospora leaf blight control. | |
| trifloxystrobin | |||||
|
1.9-2.9 fl oz
|
7
|
12
|
1.8-2.8
|
Not for aerial application in NYS. Do not make more than one foliar application before alternating to a fungicide with a different mode of action (non-QoI, Group 11) for at least one application | |
|
† = Not for use on Long Island |
|||||
|
16.5.5 Northern
root-knot nematode, Meloidogyne hapla
|
Time for concern: Planting
Key characteristics: This nematode causes
forking and galling of the main root. Roots may also turn brown. Nematodes
and their egg masses are visible at 10X magnification on galled tissue.
| Management Option | Recommendation |
| Scouting thresholds | Record the occurrence and severity of root-knot nematodes. The damage threshold is less than one egg per cubic centimeter (cc) of soil. "How to" instructions for soil sampling for nematode bioassays "How to" instructions for farmers to conduct a field test for root knot nematode using lettuce See article about on-farm method of assessing nematode population |
| Resistant varieties | No resistant varieties are available. |
| Crop rotation | Rotate out of vegetables and preferably with grain crops to reduce nematode populations. Crop rotation and disease management article |
| Cover Crops | Trudan 8, a sudan grass hybrid, has been shown to suppress the nematode on organic soils when incorportated as green manure prior to the first frost. Several cyangenic cultivars of sweet clover and flax as well as crucifer cover crops are also effective. Cornell cover crop decision tool Cornell article: "Cropping sequences and root health" Cornell Forage Species Selection Tool |
| Sanitatiom | Wash equipment after use in infested fields. |
| Site selection and Postharvest | If possible plow under crop debris and plant a grain cover crop. |
| Seed selection/treatment, | These are not currently viable management options. |
|
Compound(s) |
|||||
Cornell article: "General guidelines for managing fungicide resistance" |
|||||
Comparing Environmental Risks of Pesticides |
|||||
| Common name Trade Name |
Rate/A Product |
PHI (days) |
REI (hours) |
Field Use EIQ |
Comments |
| oxamyl | |||||
|
2 lb/gal |
|
|
|
|
Not for use in Nassau/Suffolk Counties. Preplant, broadcast and incorporated |
|
*† Vydate
L |
1-2
gal
|
14
|
48
|
32-63.9
|
Not for use in Nassau/Suffolk Counties. In-furrow |
|
* Restricted use pesticide. † Not for use in Nassau/Suffolk Counties |
|||||
Time for concern: Any growth stage,
but especially late in the season and close to harvest.
Key characteristics: Root decay may occur
before wilt is visible on aboveground plant parts. A cottony, white
mycelium appears on the affected area, especially lower plant parts
and roots. On or inside the mycelium are black structures 1/10 to 2/5
inch wide.
| Management Option | Recommendation |
| Scouting/thresholds | Record the occurrence and severity of white mold. Begin spraying when the disease first appears. |
| Coverage | The best coverage can be obtained by using 50 gallons per acre at 100 to 200 psi.Thorough coverage of the lower plant tissue is essential. |
| Resistant varieties | No resistant varieties are available. |
| Site selection | Avoid planting in shaded areas and in small fields surrounded by trees; do not plant in fields that drain poorly or have a history of severe white mold. |
| Sanitation and postharvest | If possible deep plowing once per year to bury sclerotia eight to ten inches deep may reduce disease incidence. Plow under crop debris and plant a grain cover crop. |
| Crop rotation | Rotate away from vegetables for a minimum of 3 years, longer if possible. Crop rotation and disease management article Cornell cover crop decision tool Cornell Forage Species Selection Tool |
| Biological control | See Cornell poster: "Biological control of Sclerotinia sclerotiorum" |
| Seed selection/treatment | These are not currently viable management options. |
|
Compound(s) |
|||||
Cornell article: "General guidelines for managing fungicide resistance" |
|||||
Comparing Environmental Risks of Pesticides |
|||||
| Common name Trade Name |
Rate/A Product |
PHI (days) |
REI (hours) |
Field Use EIQ |
Comments |
| coniothyrium minitans | |||||
|
2-4
lb/
50-100 gal water |
0
|
4
|
0.7-1.4
|
This biological fungicide has been tested in some states; however, limited information is available on effectiveness in our region. Apply 3 to 4 months prior to plantinng to allow the active agent to reduce inoculum levels of sclerotia in soil. following application, incorporate to a depth of 1 to2 inches but do not plow before seeding carrots to avoid untreated sclerotia in lower soil layers from infesting the upper soil level. | |
Time for concern: Planting
Key characteristics: Seeds may become infected
and decayed prior to or shortly after germination.
| Management Option | Recommendation |
| Crop rotation | Rotate out of vegetables and preferably with a grain crop. Crop rotation and disease management article Cornell cover crop decision tool Cornell article: "Cropping sequences and root health" Cornell Forage Species Selection Tool |
| Site selection | Plant on well-drained, good structure, and healthy soil. SARE Publication: "Building Soils for Better Crops" SARE publication: "Managing Cover Crops Profitably" |
| Resistant varieties | No resistant varieties are available. |
| Seed selection/treatment | Plant vigorous and disease free seed treated with Apron plus thiram or Maxim. Seed treatments can reduce the loses to seed decay and damping-off organisms on seeds and in soils. |
| Scouting thresholds, Postharvest, and Sanitation | These are not currently viable management options. |
| Compound(s) | Apron and Maxim seed treatments are effective. See above. |
Time for concern: Harvest and storage
Key characteristics: Symptoms vary depending
on the fungus or bacterium causing the problem.
| Management Option | Recommendation |
| Resistant varieties | No resistant varieties are available. |
| Site selection | Rots are usually more severe from poorly drained sites and from carrots harvested late and poorly handled during harvest. |
| Postharvest | Immediately after digging, remove the damaged roots and place the healthy roots in storage at 32¡F and 90 to 95 percent relative humidity. |
| Sanitation | Although storage bins are not an important source of disease, they should be cleaned. |
| Scouting thresholds, Crop rotation, and Seed selection/treatment | These are not currently viable management options. |
|
Compound(s) no compounds available |
| Aphids | Aster
leafhopper | Carrot Rust Fly |
| Carrot Weevil |
Wireworms |
SARE Publication: "Manage Insects on Your Farm: A Guide to Ecological Strategies"
SARE Publication: "A Whole-Farm Approach to Managing Pests"
See pictures of the GPA life cycle
Cornell presentation 'Nault': "Overview of insect management in carrots"
Time for concern: June through harvest
Key characteristics: Adults vary in color. Aphids are generally about 1/16 inch long. Aphid infestations usually occur on new growth causing yellowing or wilting of foliage.
| Management Option | Recommendation |
| Scouting/thresholds | When aphids appear in sweep nets, randomly sample 50 plants in the field to determine the percentage of plants infested. Check the newest leaves for the presence of aphids. If more than 25 percent of plants are infested, an insecticide treatment is recommended. See Reference 1. |
| Resistant varieties | No resistant varieties are available. |
| Natural enemies | Natural enemies are helpful in controlling aphid populations. They can be preserved by using insecticides that are less harmful to them. Use Reference 3 for identification of natural enemies. Coleomegilla maculata lengi, Hippodamia convergens, Coccinella septempunctata, Cocinella tranversogutatta, Cycloneda munda, Hippodamia variegata, Aphidoletes aphiimyza, Aphidius matricariae, Diaeretiella rapae, Praon aguti, Praon occidentale, Ephedrus incompletus, Lysephlebus testaceipes, Aphelinus semiflavus, Pandora neoaphidis Michigan State site "Enhancing Beneficial Insects with Native Plants" ATTRA publication: "Farmscaping to enhance biological control" |
| Note(s) | Aphid populations decline rapidly during periods of heavy rainfall. Insecticides applied for leafhoppers may also suppress aphids. |
| Insecticide Resistance Management |
A classification of insecticides based on their mode of action is available in pdf format. This guide can be used to help avoid or delay the development of insecticide resistance, as well as manage populations that have developed resistance to a particular insecticide. It is a large file - 97 page, 780k pdf file |
| Crop rotation, Site selection, Postharvest, and Sanitation | These are not currently viable management options. |
|
Compound(s) |
|||||
Comparing Environmental Risks of Pesticides |
|||||
| Common name Trade Name |
Rate/A Product |
PHI (days) |
REI (hours) |
Field Use EIQ |
Comments |
| endosulfan | |||||
|
*Thionex
3 EC |
2/3-1-1/3
|
7
|
48
|
16.9-34.7
|
|
imidacloprid |
|||||
*Admire Pro Systemic Protectant |
4.0-10.5 fl oz |
21 |
12 |
4.3-10.3 |
Soil Applications Only (see label for details). |
imidacloprid + cyfluthrin |
|||||
*Leverage 2.7 |
3.5 fl oz |
7 |
12 |
2.4 |
Maximum per season is 10.5 fl oz |
thiamethoxam |
|||||
*† Platinum 75SG |
1.7-4.01 oz |
- |
12 |
2.7-6.3 |
See label restrictions. |
* Restricted use pesticide.
† Not for use in Nassau/Suffolk Counties.
Ontario Canada fact sheet on aster leafhopper/aster yellows
Cornell presentation 'Nault': "Overview of insect management in carrots"
Time for concern: June through
August
Key characteristics: The adult aster leafhopper
is about 3/16 inch long and pale green with six, black spots on the
front of its head. Nymphs resemble adults but are smaller and lack wings.
The aster leafhopper transmits the pathogen for aster yellows disease.
Symptoms of aster yellows include yellowing of leaves in the center
of the crown. New shoots are sickly and appear like a "witch's
broom." Older leaves take on red and/or white coloration. Roots
may be altered in color and flavor.
| Management Option | Recommendation |
| Scouting/thresholds | Record the occurrence and severity of aster leafhoppers. Yellow sticky cards can be used to monitor leafhopper activity, especially rapid increases in infestations. A foliar insecticide should be applied at the first appearance of leafhoppers. Spray up to three applications at ten day intervals. For areas where yellows disease has been a problem, follow a seven day spray schedule; continue spraying through August or until leafhoppers can no longer be found in the field. An aster yellows index has been developed in the midwest and uses the average infectivity of leafhoppers, number of leafhoppers per sweep, and cultivar susceptibility to determine if an insecticide is needed. See Reference 1. Because it takes a month for yellows symptoms to appear, spraying for aster leafhoppers can be discontinued one month before harvest. |
| Natural enemies | Natural enemies may help to control aster leafhopper populations. Use Reference 3 for identification of natural enemies. Michigan State site "Enhancing Beneficial Insects with Native Plants" ATTRA publication: "Farmscaping to enhance biological control" |
| Note(s) | The younger the plant at the time of infection, the more severe the damage from aster yellows. Control weeds that harbor aster yellows. Sowing seed at higher densities can reduce leafhopper numbers and incidence of yellows. |
| Resistant varieties | Cultivars vary in susceptibility to aster yellows. See Reference 1. |
| Site selection | Avoid planting near lettuce or other susceptible crops. Leafhoppers migrate from grain fields, so plant as far away from grains as possible. |
| Postharvest | Crop debris should be destroyed as soon as possible to remove this source of disease for other plantings and to initiate decomposition. |
| Insecticide Resistance Management |
A classification of insecticides based on their mode of action is available in pdf format. This guide can be used to help avoid or delay the development of insecticide resistance, as well as manage populations that have developed resistance to a particular insecticide. It is a large file - 97 page, 780k pdf file |
| Crop rotation and Sanitation | These are not currently viable management options. |
Compound(s) |
|||||
Comparing Environmental Risks of Pesticides |
|||||
| Common name Trade Name |
Rate/A Product |
PHI (days) |
REI (hours) |
Field Use EIQ |
Comments |
| beta-cyfluthrin | |||||
1 lb/gal |
0.4-0.7
|
||||
| carbaryl | |||||
4 lb/gal |
20-40
|
||||
| esfenvalerate | |||||
0.66 lb/gal |
7 | ||||
imidacloprid |
|||||
Admire Pro Systemic Protectant |
4.0-10.5 fl oz |
21 |
12 |
4.3-10.3 |
Soil Applications Only (see label for details). |
imidacloprid + cyfluthrin |
|||||
*Leverage 2.7 |
3.5 fl oz |
7 |
12 |
2.4 |
Maximum per season is 10.5 fl oz |
thiamethoxam |
|||||
*† Platinum 75SG |
1.7-4.01 oz |
- |
12 |
2.7-6.3 |
See label restrictions. |
* Restricted use pesticide.
† Not for use in Nassau/Suffolk Counties.
Cornell presentation 'Nault': "Overview of insect management in carrots"
Time for concern: mid-May until
harvest
Key characteristics: Adults are 6 mm
long, slender, shiny and black and have red heads and long yellow
legs. Eggs are laid on the ground. Young larvae burrow into the soil
and initially feed on root hairs and rootlets, whereas older larvae
typically tunnel within the lower one-third of the root. Larvae may
kill young plants and injury to older plants may allow entry by pathogens
that will cause roots to rot. There are 2 to 3 generations per year.
This is an uncommon pest in New York. See www.nysaes.cornell.edu/ent/factsheets/.
| Management Option | Recommendation |
| Scouting/thresholds | Flies are monitored using yellow sticky traps. Traps should be placed just above the carrot canopy and within the first couple of rows along the field edges. Fields that are sheltered by woods are often at higher risk than those that are in open areas. Damage is often most prevalent along field edges. There should be an average of 2.5 to 5 sticky traps per acre. Traps should be monitored 1 to 2 times per week. The action threshold is 0.1 flies/trap/day. Spray in early evening when flies are in the field. Spraying to control flies is not necessary within one month of harvest because it takes at least one month for larvae to enter roots after eggs are laid. Note: No foliar-applied products are currently registered to control carrot rust fly on carrot. |
| Resistant varieties | No resistant varieties are available. |
| Natural enemies | Little is known about the effect of biocontrol on carrot rust flies. Michigan State site "Enhancing Beneficial Insects with Native Plants" ATTRA publication: "Farmscaping to enhance biological control" |
| Planting date | Carrots seeded after mid-May may avoid serious injury by carrot rust fly. |
| Crop Rotation | Crop rotation is effective as long as fields are rotated at least 1 mile away from previous year's carrot fields. |
| Site selection, Postharvest and Sanitation |
Select fields that are not sheltered by trees or tend to be very humid. Do not plant fields near fields that had high infestations of carrot rust flies the previous season. The number of overwintering flies will be reduced if crop debris is removed after harvest. |
Compound(s) |
|||||
Comparing Environmental Risks of Pesticides |
|||||
| Common name Trade Name |
Rate/A Product |
PHI (days) |
REI (hours) |
Field Use EIQ |
Comments |
| clothianidin + imidacloprid | |||||
0.75 lb/lb |
-
|
Growers must purchase seed treated by seed company outside of New York. | |||
Cornell presentation 'Nault': "Overview of insect management in carrots"
Time for concern: mid-May until harvest
Key characteristics: Adults are dark-brown,
snout-nosed beetles that are about 6 mm long. Adults lay 2-3 eggs
in the petioles or crown of the carrots beginning in the first true
leaf stage. Eggs hatch in one to two weeks and white, grub-like
larvae either tunnel down into the root or leave the stalk and bore
into the side of the root from beneath the soil. Larvae may kill
young plants. Damage to older plants istypically observed in the
upper one-third of the root. Feeding injury may allow entry by pathogens
that will cause roots to rot. There are 2 generations per year.
This is an uncommon pest in New York. See www.nysaes.cornell.edu/ent/factsheets/.
| Management Option | Recommendation |
| Scouting/thresholds | Weevils are monitored by taking 2- to 4-inch sections of mature carrot roots and placing them vertically in the soil between rows. Five to 10 groups of 5 root sections are positioned within the first several rows along the fieldÕs edges. The presence of adults is determined by monitoring oviposition punctures made in the root pieces. The action threshold is 0.3 punctures per root-piece per day, or over 25% of the root pieces with punctures. Apply one or two sprays 10 to 14 days apart when most adults have left their overwintering site but before they start laying eggs. |
| Resistant varieties | No resistant varieties are available. |
| Natural enemies | Natural enemies will feed on carrot weevil eggs, larvae and occasionally adults. Minimizing use of insecticides will help preserve populations of natural enemies. Michigan State site "Enhancing Beneficial Insects with Native Plants" ATTRA publication: "Farmscaping to enhance biological control" |
| Insecticide Resistance Management |
A classification of insecticides based on their mode of action is available in pdf format. This guide can be used to help avoid or delay the development of insecticide resistance, as well as manage populations that have developed resistance to a particular insecticide. It is a large file - 97 page, 780k pdf file |
| Crop rotation |
Crop rotation is quite effective because adults rarely fly. Fields should be rotated as far away as possible from previous year's carrot fields (at least 0.5 to l mile away). Rotate with non-umbelliforous plants whenever possible. |
| Site selection, Postharvest and Sanitation | Remove crop debris after harvest to remove food source and reduce carrot weevils ability to overwinter. Crop debris may also serve as a host early the following spring |
|
Compound(s) |
|||||
Comparing Environmental Risks of Pesticides |
|||||
| Common name Trade Name |
Rate/A Product |
PHI (days) |
REI (hours) |
Field Use EIQ |
Comments |
| beta-cyfluthrin | |||||
1 lb/gal |
0.7
|
Maximum number of applications
is 5/season. Do not exceed 14 fl oz A/season |
|||
| esfenvalerate | |||||
|
*Asana
XL |
9.6
oz
|
7
|
12
|
2
|
|
|
*Restricted use pesticide. Check NYS PIMS (Product, Ingredient, and Manufacturer System) to see if the label is current for New York. SPECIAL NEW YORK RESTRICTIONS MAY APPLY. (http://pims.psur.cornell.edu/) |
|||||
See pictures of the wireworm life cycle
See pictures of wireworm damage
Cornell presentation 'Nault': "Overview of insect management in carrots"
Time for concern: June through September
Key characteristics: Adults are known as “click beetles” because of the structure on the ventral side with which they are able to right themselves if inverted. The head and thorax of adults are dark brown; the legs and wing covers vary from pale yellow to mahogany. Eggs are small, pearly white, and spherical. The newly hatched larva or wireworm is white and 2/25 inch long. Mature larvae are cylindrical, tan, and range from 1/2 to 1 inch in length. Damage is confined to the underground part of the plant. See www.nysaes.cornell.edu/ent/factsheets/.| Management Option | Recommendation |
| Scouting/thresholds | Prior to planting, bait stations can be used to monitor populations. Place several ounces of coarse whole-wheat flour or a mixture of untreated corn and wheat seed or pieces of carrot (or potato) into a fine mesh pouch (e.g. panty hose), and bury six to 14 inches. Cover the soil over the bait station first with a piece of black polyethylene plastic and then with a piece of clear polyethylene film. Secure the edges of the film with soil. Prior to planting, remove the soil above and around the bait station and count the larvae in and around the bait. Alternatively, midsummer sampling can be done by sifting one square foot of soil to a depth of six to 14 inches and counting the wireworms. Use a box with a base made of 1/4-mesh hardware cloth as a sieve. Take six to 12 samples, starting in low, wet areas. Threshold: if half or more of the bait stations or soil samples contain one or more wireworms, the soil should be treated with an insecticide or carrots should not be grown. |
| Resistant varieties | No resistant varieties are available. |
| Insecticide Resistance Management | A classification of insecticides based on their mode of action is available in pdf format. This guide can be used to help avoid or delay the development of insecticide resistance, as well as manage populations that have developed resistance to a particular insecticide. It is a large file - 97 page, 780k pdf file |
| Crop rotation | In some cases, wireworm infestations are initiated in wheat, barley, timothy and clover rotational crops. In these situations, substitution of a row crop such as corn in the rotation is advisable. Treatment of rotational field corn with approved soil insecticides may reduce wireworm problems in following carrot crops. |
| Site selection and Sanitation | Avoid planting in poorly drained soils or wet areas. Keeping land free of grassy weeds during the egg-laying period (May through late June) will greatly reduce the potential for infestation. |
Compound(s) |
|||||
Comparing Environmental Risks of Pesticides |
|||||
| Common name Trade Name |
Rate/A Product |
PHI (days) |
REI (hours) |
Field Use EIQ |
Comments |
| diazinon | |||||
* Diazinon AG500 |
3-4 qts |
- |
72 |
127-169 |
Broadcast just before planting and immediately incorporate into the top 4 to 8 inches of soil. |
*Restricted use pesticide. Check NYS PIMS (Product, Ingredient, and Manufacturer System) to see if the label is current for New York. SPECIAL NEW YORK RESTRICTIONS MAY APPLY. (http://pims.psur.cornell.edu/) |
|||||
Key characteristics: Weed fact sheets provide
a good color reference for common weed identification. See
Reference 4. Also
see Virginia
Tech Weed Identification Guide.
Cornell Weed Ecology and Management Laboratory website
Ontario, Canada weed identification gallery
SARE Publication: "A Whole-Farm Approach to Managing Pests"
| Management Option | Recommendation |
| Scouting/thresholds |
Weeds may be unevenly distributed over a field. Localized areas of severe weed infestations or atypical conditions, such as poorly drained areas, high spots, and field edges, may be recorded on a weed map. A weed map should be on file for each field. Make a rough sketch of the field, including landmarks, boundaries, crop row direction, compass directions, roads, planting date, map preparation date, and any other important details. The following information should be indicated on the map: species of weed, size of weed, density of each species, and distribution of weed. Scout fields two to three weeks after planting to evaluate the success of the current season's program and at or near harvest to help predict weed control practices that will be necessary for the following year. |
| Site selection | Refer to weed maps to avoid problem weeds when choosing fields for carrots. |
| Cultivation | Cultivation
is useful in carrot weed control due to a small number of registered
produsts and their narrow weed control spectra. |
| Banding herbicides | Banding of herbicides at planting is not useful in carrot production due to small number of registered products and their narrow weed spectra. |
| Cover Crops, Weed Seed Bank Assessment | See report on using buckwheat as a weed control cover crop See report on estimating weed seed banks SARE publication: "Managing Cover Crops Profitably" Cornell cover crop decision tool Cornell buckwheat cover crop handbook Cornell Forage Species Selection Tool |
Comparing Environmental Risks of Pesticides |
| Compounds: (Listed from earliest to latest application timing.) | ||||
| TIMING KEY: PPI = pre-plant incorporated; PreE = pre-emergence; PostE = post-emergence | ||||
Timing |
||||
PPI |
PreE |
PostE |
PRODUCT NAME (active ingredient, weight of active per unit of herbicide) | |
| Notes | ||||
X |
Treflan HFP (trifluralin, 4 lb/gal) | |||
Weeds Controlled: |
grasses and some broadleaves except ragweed, galinsoga, and mustard | |||
Rates (per acre): |
0.5-1 qt | |||
AI per acre (lbs./acre): |
0.5-1.0 | |||
PHI (days): |
||||
REI (hours): |
12 | |||
Field Use EIQ: |
8.1-16.2 | |||
Comments: |
Use the higher rate on heavier soils. Ineffective on muck soils. | |||
Timing |
||||
PPI |
PreE |
PostE |
PRODUCT NAME (active ingredient, weight of active per unit of herbicide) | |
| Notes | ||||
X |
Prowl H20 (pendimethalin, 3.8 lb/gal) | |||
Weeds Controlled: |
annual grasses, suppression of some annual broadleaves | |||
Rates (per acre): |
2 pt | |||
AI per acre (lbs./acre): |
0.95 | |||
PHI (days): |
60 | |||
REI (hours): |
24 | |||
Field Use EIQ: |
23.4 | |||
Comments: |
Apply preemergence within 2 days of planting. Do not exceed 2 pt/acre/season. | |||
Timing |
||||
PPI |
PreE |
PostE |
PRODUCT NAME (active ingredient, weight of active per unit of herbicide) | |
| Notes | ||||
X |
*†Dual Magnum (*s-metolachlor, 7.62 lb/gal) | |||
Weeds Controlled: |
annual grasses, yellow nutsedge, hairy galinsoga, suppression of other broadleaf weeds | |||
Rates (per acre): |
Mineral soil: 0.67-1.33 pt; muck soil: 1.33-2 pt | |||
AI per acre (lbs./acre): |
Mineral soil: 0.64-1.24; muck soil: 1.24-1.9 | |||
PHI (days): |
60 | |||
REI (hours): |
24 | |||
Field Use EIQ: |
Mineral soil: 12-25; muck soil: 25-37 | |||
Comments: |
NOT FOR USE IN NASSAU/SUFFOLK COUNTIES.This is a Special Local Needs (SLN) registration that requires indemnification due to a wider range of Dual Magnum rates and application methods than the federal Section 3 registration. Growers must have a copy of the SLN label in their possession and sign off on the indemnification if they choose to follow the recommendations in these guidelines. SLN indemnified labels and the indemnification agreement can be found by logging in at www.farmassist.com. (New users must create an account.) Once logged in, labels are available under the products menu at the top of the screen under “Indemnified Labels.” If difficulties are encountered in using the website, click the support link at the top of the FarmAssist web page to contact Syngenta. Apply a single application after planting but before crop or weeds emerge (i.e. preemergence). Banded applications may be made. Avoid concentration in the seed furrow. Do not make broadcast applications to carrots planted in furrows more than 2 in deep. | |||
Timing |
||||
PPI |
PreE |
PostE |
PRODUCT NAME (active ingredient, weight of active per unit of herbicide) | |
| Notes | ||||
X |
Lorox (linuron, 0.5 lb/lb) | |||
Weeds Controlled: |
grasses and broadleaves | |||
Rates (per acre): |
0.25-.5 lb | |||
AI per acre (lbs./acre): |
0.125-0.25 | |||
PHI (days): |
14 | |||
REI (hours): |
24 | |||
Field Use EIQ: |
2.4-4.8 | |||
Comments: |
For control of emerged broadleaf weeds early in the development of the carrot crop apply 0.25 lb product/A to carrots having at least 1 fully-developed true leaf and 0.5 lb to carrots having 3 or more leaves. A single application applied at the 5-leaf stage of carrots will not provide adequate season-long control. Multiple applications at 1- and 3-, 2- and 4-, or 3- and 5-leaf stages will significantly improve weed control and reduce competition with the crop. Some crop injury has been seen in research trials however, yield reductions have not occurred. The activity of Lorox on both carrots and weeds increases if applied after 3 days of cloudy weather. If spraying is done under these conditions, rates should be reduced. Do not apply when the temperature is greater than 85°F. Lorxox often reacts with other pesticides and may damage the crop. Several days should elapse between applications of Lorox and insecticides. | |||
Timing |
||||
PPI |
PreE |
PostE |
PRODUCT NAME (active ingredient, weight of active per unit of herbicide) | |
| Notes | ||||
X |
METRIBUZIN (several formulations) | |||
Weeds Controlled: |
grasses and broadleaves | |||
Rates (per acre): |
See labels. | |||
AI per acre (lbs./acre): |
0.25 | |||
PHI (days): |
60 | |||
REI (hours): |
12 | |||
Field Use EIQ: |
7 | |||
Comments: |
Apply specified dosage per acre as a broadcast spray over the tops of carrot plants. Application should be made after carrots have formed 5 to 6 true leaves but before weeds are 1 inch in height or diameter. If needed, a second application may be made after an interval of at least 3 weeks. | |||
Timing |
||||
PPI |
PreE |
PostE |
PRODUCT NAME (active ingredient, weight of active per unit of herbicide) | |
| Notes | ||||
X |
*Select Max(clethodim, 0.97 lb/gal) | |||
Weeds Controlled: |
annual and perennial grasses | |||
Rates (per acre): |
12-16 fl. oz. | |||
AI per acre (lbs./acre): |
0.091-0.12 | |||
PHI (days): |
30 | |||
REI (hours): |
24 | |||
Field Use EIQ: |
1.6-2.1 | |||
Comments: |
For control of numerous annual and perennial grasses. DO NOT apply more than 0.5 lb ai per acre per season. Application on LONG ISLAND is restricted to no more than 0.25 lb ai per acre per season. Always use only 0.25% v/v non-ionic surfactant (NIS) with *Select Max. | |||
Timing |
||||
PPI |
PreE |
PostE |
PRODUCT NAME (active ingredient, weight of active per unit of herbicide) | |
| Notes | ||||
X |
Fusilade DX(fluazifop p-butyl, 2 lb/gal) | |||
Weeds Controlled: |
annual grasses and barley windbreaks | |||
Rates (per acre): |
12 fl. oz. | |||
AI per acre (lbs./acre): |
0.188 | |||
PHI (days): |
45 | |||
REI (hours): |
12 | |||
Field Use EIQ: |
5.3 | |||
Comments: |
Apply when grasses are actively growing. | |||
Timing |
||||
PPI |
PreE |
PostE |
PRODUCT NAME (active ingredient, weight of active per unit of herbicide) | |
| Notes | ||||
X |
POAST (sethoxydim, 1.5 lb/gal) | |||
Weeds Controlled: |
annual grasses | |||
Rates (per acre): |
1-1.5 pt | |||
AI per acre (lbs./acre): |
0.188-0.28 | |||
PHI (days): |
30 | |||
REI (hours): |
12 | |||
Field Use EIQ: |
3.8-5.6 | |||
Comments: |
Apply when grasses are actively growing and not under stress. Apply with 2 pts of oil concentrate per acre. | |||
Timing |
||||
PPI |
PreE |
PostE |
PRODUCT NAME (active ingredient, weight of active per unit of herbicide) | |
| Notes | ||||
X |
Aim EC (carfentrazone, 2 lb/gal) | |||
Weeds Controlled: |
||||
Rates (per acre): |
0.8-1.6 fl oz/ application | |||
AI per acre (lbs./acre): |
0.012-0.025 | |||
PHI (days): |
0 | |||
REI (hours): |
12 | |||
Field Use EIQ: |
0.2-0.5 | |||
Comments: |
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 Check NYS PIMS (Product, Ingredient, and Manufacturer System) to see if the label is current for New York. SPECIAL NEW YORK RESTRICTIONS MAY APPLY. (http://pims.psur.cornell.edu/) |
||||
1 Foster, R., and B. Flood. 1995. Vegetable Insect Management: With Emphasis on the Midwest. Willoughby, Ohio: Meister.
2 Dillard, H. R. 1988. Carrot leaf blight, p. 739.00. In Vegetable Crops: Diseases of Carrot. New YorkState Agricultural Experiment Station, Geneva.
3 Hoffmann, M. P., and A. C. Frodsham. 1993. Natural Enemies of Vegetable Insect Pests. Cornell Cooperative Extension. 64 pp.
4 Pennsylvania State University. 1987. Weed identification, pp. 1-32. Pennsylvania State University Cooperative Extension, University Park.
World Wide Web Sites:
BIOLOGICAL CONTROL: A Guide to Natural Enemies in North America:
http://www.nysaes.cornell.edu/ent/biocontrol/
IPM Vegetable Fact Sheets:
http://nysipm.cornell.edu/factsheets/vegetables/default.asp
Pests in the Northeastern United States
http://www.nysaes.cornell.edu/ent/factsheets
Plant Disease Diagnosis Clinic:
http://PlantClinic.cornell.edu
Vegetable MD Online:
http://vegetablemdonline.ppath.cornell.edu/Home.htm
Measuring Environmental Impact of Pesiticides:
http://nysipm.cornell.edu/publications/eiq/default.asp
See Cornell Soil Health website and manual
USDA Sustainable Agriculture Research and Education Publications (SARE)
Appropriate Technology Transfer for Rural Areas (ATTRA): http://www.attra.org/
Cornell Small Farms Program
Take on-line courses in IPM for pesticide recertification credits
|
Next
chapter
Celery |
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Maintained by Curtis Petzoldt, New York State IPM Program.
Last modified November 15, 2012.