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. Cultivars vary in susceptibility to aster yellows. See Reference 1.

16.2 Planting Methods

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.

Table 16.2.1 Recommended spacing.

Row Seed

Type (inches) In-row (lb/acre)

Imperator or Nantes 18-36 1.5” 2 to 3

Chantenay or Danvers 18-36 1.5” 1 to 2

16.3 Fertility

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

16.4 Harvesting

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.

Table 16.3.1 Recommended nutrients based on soil tests.
N pounds/acre	P₂O₅ pounds/acre			K₂O pounds/acre			Comments
	Soil Phosphorus Level			Soil Potassium Level
	low	med.	high	low	med.	high

*80-90*	*120*	80	40	*160*	*120*	60	*Total recommended*

30-40	80	40	0	120	80	20	Broadcast and disk-in.
20	40	40	40	40	40	40	Deep drill or band place with planter
30	0	0	0	0	0	0	Sidedress 4-6 weeks after seeding Sidedress twice in years with heavy rainfall

16.5 Disease Management

16.5.1 Aster yellows, The pathogen responsible for this disease is aster yellows phytoplasma, previously known as mycoplasma-like or MLOs. The aster yellow phytoplasma overwinters in the body of the adult aster leafhopper, although it may also be transmitted by other species of leafhoppers.

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 purple to 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.

16.5.2 Cavity spot, Pythium violae; Pythium spp.

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.
Crop rotation			Minimum three year rotation out of vegetables and alfalfa.
Site selection			Select fields with well drained, light textured and healthy soils.
Seed selection/treatment			Plant vigorous, disease-free seed that has been treated with fungicides (Apron+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)
Common name		Rate/A		PHI	REI	Field
	Trade name	Product		(days)	(hours)	Use EIQ	Comments
mefenoxam
	Ridomil Gold EC	1-2 pt		—	48	14-28	Rates are for PPI or surface application.

16.5.3 Rhizoctonia Crown rot and Foliar blight diseases (Crater rot and foliar blight are caused by Rhizoctonia solani and its sexual state Thanatephorus cucumeris).

Time for concern: Planting through the end of the season

Key characteristics: Crater rot - symptoms result from infections of R. solani 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 cankers. 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 crater 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.

*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.
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.
Sanitation	These are not currently viable management options.
Compound(s)	Quadris, Amistar, Cabrio, and Rovral 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

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 wet and warm weather. 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. 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 leaves. Because it develops rapidly in hot and 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.
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.
Crop rotation			Minimum 2 to 3 year rotation out of carrots is effective against the three diseases.
Soil maintainance			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.
Seed selection/treatment			Plant only disease-free and treated seeds. All three diseases can be seed borne. Hot water treatment of seeds reduces bacterial leaf blight.
Postharvest			Crop debris should be destroyed as soon as possible to remove this source of inoculum 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
boscalid
	Endura 70 WDG	4.5 oz		0	12	9	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).
azoxystrobin
	Quadris F	9.2-15.4 fl oz		0	4	2-3	For control of Alternaria and Cercospora leaf blights and has activity against Rhizoctonia foliar blight. Do not apply more than 2 sequential applications of these products 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.
	Amistar 80 WDG	3-5 oz		0	4	2-3.5
azoxystrobin + chlorothalonil
	Quadris Opti	2.4 pt		0	12
chlorothalonil
	Bravo, Equus or OLF 6 lb/gal	1.5-2 pt		0	12	33-43	Note eye wash requirement and reduced seasonal amounts for shortened reentry interval on label. Controls Alternaria and Cercospora leaf blights.
chlorothalonil + zinc
	Bravo Zn 4.17 lb/gal	2.25-2.75 pt		0	12/48 (see label)	35-43	Supplemental labeling must be in possession at time of application.
copper compounds
	Champ F or OLF	1 1/3 pt		0	24	19	Label varies with manufacturer and formulation. Controls bacterial leaf blight.
iprodione
	Rovral 50 WP 0.5 lb/lb	1-2 lb		0	24	6-11	Controls Alternaria leaf blight. and has activity against Rhizoctonia foliar blight (Group 2 fungicide).
	Rovral 4F 4 lb/gal	1-2 pt		0	24	5-9
Compound(s)
Common name		Rate/A		PHI	REI	Field
	Trade name	Product		(days)	(hours)	Use EIQ	Comments
pyraclostrobin
	Cabrio EG	8-12 oz		0	12		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
	Pristine 38 WDG	8-10.5 oz		0	12

16.5.5 Northern root-knot nematode, Meloidogyne hapla

Time for concern: Before and during planting

Key characteristics: This nematode causes forking and galling of the main root as well as the fine fibrous roots.. Severely infected plants are stunted and damage usually occurs in irregularly shaped areas. 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.
Resistant varieties			No resistant varieties are available.
Crop rotation			Rotate out of vegetables and preferably with grain crops to reduce nematode population.
Cover Crops			Trudan 8, a Sudan grass hybrid, has been shown to suppress the nematode on organic soils when incorporated as a green manure prior to the first frost. Several cyanogenic cultivars of sweet clover and flax, as well as crucifer cover crops, are also effective.
Sanitation			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)
Common name		Rate/A		PHI	REI	Field
	Trade name	Product		(days)	(hours)	Use EIQ	Comments
oxamyl
	†*Vydate L 2 lb/gal	2-4 gal		14	48	92-183	Not for use in Nassau/Suffolk Counties. Preplant, broadcast and incorporated
	†*Vydate L 2 lb/gal	1-2 gal		14	48	46-92	Not for use in Nassau/Suffolk Counties. In-furrow, drench, or band incorporated
*Restricted use only		† Not for use in Nassau/Suffolk Counties

16.5.6 Sclerotinia white mold, Sclerotinia sclerotiorum

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 (sclerotia) 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 three years, longer if possible.
Seed selection/treatment			These are not currently viable management options.
Compound(s)
Common name		Rate/A		PHI	REI	Field
	Trade name	Product		(days)	(hours)	Use EIQ	Comments
Coniothyrium minitans
	Contans WG	2-4 lb/ 50-100 gal water		0	4		See comments below.
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 the onset of disease to allow the active agent to reduce inoculum levels of sclerotia in soil. Following application, incorporate to a depth of 1 to 2 inches but do not plow before seeding carrots to avoid untreated sclerotia in lower soil layers from infesting the upper soil level.

16.5.7 Seed decay, primarily caused by the pathogens Pythium spp. and Rhizoctonia spp.

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.
Site selection	Plant on well-drained, good structure and healthy soil.
Resistant varieties	No resistant varieties are available.
Seed selection/treatment	Plant vigorous and disease free seed treated with Apron plus thiram and/or Maxim. Seed treatments can reduce the losses to seed decay and damping-off organisms on seeds and in the soil.
Scouting/thresholds, Postharvest, and Sanitation	These are not currently viable management options.
Compound(s)	Apron and Maxim seed treatments are effective.

16.5.8 Storage rots

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.

16.6 Insect Management

16.6.1 Aphids, Primarily the green peach aphid, Myzus persicae

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. See www.nysaes.cornell.edu/ent/factsheets/.

*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.
Note(s)			Aphid populations decline rapidly during periods of heavy rainfall. Insecticides applied for leafhoppers may also suppress aphids.
Crop rotation, Site selection, Postharvest, 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 AG500 4 lbs/gal	1 pt		14	24	21
endosulfan
	*Thionex 3 EC 3 lb/gal	0.67-1.33 qt		7	24	19-38
imidacloprid
	*Provado 1.6F 1.6 lb/gal	3.5 fl oz		7	12	5	Maximum of 10.5 fl oz allowed per season.
* Restricted use only.

16.6.2 Aster leafhopper, Macrosteles quadrilineatus, transmits the pathogen for carrot yellows disease

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. See www.nysaes.cornell.edu/ent/factsheets/.

*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.
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.
Crop rotation 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
beta-cyfluthrin
	*Baythroid XL 1 lb/gal	1.6-2.8 fl oz		0	12	<1
carbaryl
	Sevin XLR Plus 4 lbs/gal	1 to 2 qts		7	12	18-37	Frequent sprays may increase aphid infestations.
esfenvalerate
	*Asana XL 0.66 lb/gal	5.8-9.6 oz		7	12	1-2
imidacloprid
	*Provado 1.6F 1.6 lb/gal	3.5 fl oz		7	12	1	Maximum of 10.5 fl oz allowed per season.
* Restricted use only.

16.6.3 Carrot rust fly, Psila rosae (Fabricius)

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.
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)
Common name		Rate/A		PHI	REI	Field
	Trade name	Product		(days)	(hours)	Use EIQ	Comments
diazinon
	*Diazinon 50W	4 lb or 1.5 oz/1,000 sq ft		14	24	87	Apply as a drench in seed furrow at planting.
* Restricted use only.

16.6.4 Carrot weevil, Listronotus oregonensis (Le Conte)

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 is typically 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 field’s 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.
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)
Common name		Rate/A		PHI	REI	Field
	Trade name	Product		(days)	(hours)	Use EIQ	Comments
beta-cyfluthrin
	*Baythroid XL 1 lb/gal	2.8 fl oz		0	12	<1	Maximum number of applications is 5/season. Do not exceed 14 fl oz/A/season.
esfenvalerate
	*Asana XL 0.66 lb/gal	9.6 fl oz		7	12	2
* Restricted use only.

16.7 Weed Management

Key characteristics: Weed fact sheets provide a good color reference for common weed identification. See Reference 4. 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
trifluralin (grasses and some broadleaves except ragweed, galinsoga, and mustard)
	Treflan HFP 4 lb/gal	0.5-1 qt		12	13-27	Use the higher rate on heavier soils. Ineffective on muck soils.
preemergence
s-metolachlor (annual grasses, yellow nutsedge, hairy galinsoga, suppression of other broadleaf weeds)
	*†Dual Magnum 7.62EC 7.62lb/gal	Mineral 0.67-1.33 pt Muck 1.33-2 pt	60	24	12-25 25-37	See comments below
NOT FOR USE IN NASSAU/SUFFOLK COUNTIES. 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. 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.

Compound(s)
Common name		Rate/A	PHI	REI	Field
	Trade name	Product	(days)	(hours)	Use EIQ	Comments
postemergence (grasses and broadleaves)
linuron (grasses and broadleaves)
	Lorox 0.5 lb/lb	0.25-3.0 lb		24	5-60	See comments below
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 85F. Lorxox often reacts with other pesticides and may damage the crop. Several days should elapse between applications of Lorox and insecticides.
metribuzin
	Sencor DF 0.75 lb/lb	0.16-0.33 lb	60	12	3-7	See comments below
	Sencor 4F 4 lb/gal	0.25-0.5 pt	60	12	3-6	See comments below
For control of emerged broadleaf weeds early in the development of the carrot crop apply 1/6 lb product/A to carrots having at least 1 fully-developed true leaf and 1/3 lb to carrots having 3 or more leaves. One 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 Sencor 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 85F. Sencor often reacts with other pesticides and may damage the crop. Several days should elapse between applications of Sencor and insecticides. Sencor is not to be applied with surfactants and no more than 2/3 lb of product may be applied in a growing season. On high organic matter soils, there is risk for carryover with higher rates.
postemergence (annual and perennial grasses)
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. DO NOT apply more than 32 fl. oz. of Select 2EC (0.5 lb ai) per acre per season. DO NOT apply more than 8 fl. oz. per application. Application on LONG ISLAND is restricted to no more than 16 fl. oz. of Select 2EC (0.25 lb ai/acre/ season. Always use a crop oil concentrate at 1% V/V in the finished spray volume.
fluazifop p-butyl (annual grasses and barley windbreaks)
	Fusilade DX 2 lb/gal	12 fl. oz.	45	12	8	Apply when grasses are actively growing.
sethoxydim (annual grasses)
	Poast 1.5 lb/gal	1-1.5 pt	30	12	5-7	Apply when grasses are actively growing and not under stress. Apply with 2 pts of oil concentrate per acre.

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	0.5-1.6 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

16.8 References

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 York State 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.

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Pest Management Guidelines A Cornell Cooperative Extension Publication	Cornell Guide for Pest Management of Vegetables
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