NOTES: For the disease control products listed below, one product trade name and formulation is provided for each active ingredient (common name) as an example of rates, preharvest interval (PHI), restricted entry interval (REI), and special instructions. In many cases, there are other products available with the same active ingredient. Please see Table 26 and Fungicides and Bactericides Alphabetically Listed by Trade Name for more information on products with the same active ingredients.

The symbol ^OG indicates a product is listed by the Organic Materials Review Institute (OMRI) as approved for use in organic production. See Organic Certification section for more details.

Leaf Blight/Spot (Cercospora, Septoria, or Alternaria)

Use certified, disease-free seed or treat seed with hot water or fungicides. Rotate fields. Irrigate early in the day to allow foliage to dry quickly. Use wider plant spacing and/or raised beds to improve air circulation. Plant resistant or tolerant varieties. Apply fungicides based upon a disease forecasting system.

• azoxystrobin plus chlorothalonil (Quadris Opti): 2.4 pt/A; PHI 0d, REI 12h, Groups 11 & M05. See label for tank mix precautions. Carrot only.
• azoxystrobin plus propiconazole (Quilt Xcel): 14.0 fl oz/A; PHI 14d, REI 12h, Groups 11 & 3. Carrot only.
• boscalid (Endura): 4.5 oz/A; PHI 0d, REI 12h, Group 7. Alternaria only. Do not make more than 2 applications per season. 
• difenoconazole plus cyprodinil (Inspire Super): 16.0 to 20.0 fl oz/A; PHI 7d, REI 12h, Groups 3 & 9. Carrot only.
• chlorothalonil (Bravo Weather Stik): 1.5 to 2.0 pt/A; PHI 0d carrot, 10d parsnip, REI 12h, Group M05.
• copper hydroxide (Kocide 3000): 0.75 to 1.5 lb/A; PHI 0d, REI 48h, Group M01. Do not apply in a spray solution having a pH of less than 6.5 or tank mix with Aliette. Carrot only.
• cyprodinil plus fludioxonil (Switch 6.25 WG): 11.0 to 14.0 oz/A; PHI 7d, REI 12h, Groups 9 & 12. Alternaria only. 
• fluazinam (Omega 500F): 16.0 pt/A; PHI 7d, REI 12h, Group 29. For Alternaria on carrot only. 
• fluopyram plus difenoconazole (Luna Flex): 11.0 to 13.6 fl oz/A; PHI 1d, REI 12h, Groups 3 & 7. Carrot only. Do not make more than 2 sequential applications before rotation with a non-Group 3 or 7 fungicide. 
• fluxapyroxad plus pyraclostrobin (Merivon Xemium): 4.0 to 5.5 fl oz/A; PHI 7d, REI 12h, Groups 7 & 11. 
• iprodione (Rovral 4F): 1.0 to 2.0 pt/A; PHI 0d, REI 24h, Group 2. For Alternaria on carrot only. 
• penthiopyrad (Fontelis): 16.0 to 30.0 fl oz/A; PHI 0d, REI 12h, Group 7.
• polyoxin D zinc salt (OSO 5%SC): 6.5 to 13.0 fl oz/A; PHI 0d, REI 4h, Group 19.
• Pseudomonas chlororaphis strain AFS009 (Howler^OG): 2.5 to 7.5 lbs/A; PHI 0d, REI 4h, Group BM02. Use preventatively. Labeled for greenhouse use. 
• propiconazole (Tilt): 3.0 to 4.0 fl oz/A; PHI 14d, REI 24h, Group 3. Labeled for Alternaria suppression. See label for application restrictions. 
• pydiflumetofen plus fludioxonil (Miravis Prime): 6.8 fl oz/A; PHI 7d, REI 12h, Groups 7 & 12. See label for application restrictions.
• pyraclostrobin plus boscalid (Pristine): 8.0 to 10.5 oz/A; PHI 0d, REI 12h, Groups 11 & 7. Do not alternate with other Group 11 fungicides.
• Swinglea glutinosa extract (EcoSwing^OG): 1.5 to 2.0 pt/A; PHI 0d, REI 4h, Group BM01. Carrot only. Use preventatively. Use minimum of 10 gal water/A. 
• trifloxystrobin (Flint): 2.0 to 3.0 oz/A; PHI 7d, REI 12h, Group 11. Do not graze or feed leaves/foliage of treated crops. Do not alternate with other Group 11 fungicides. 

Crater Rot (Rhizoctonia carotae)

Crater rot caused by the fungus Rhizoctonia carotae is a post-harvest disease of carrot that can occur during prolonged cold storage (greater than 30 days). The disease is characterized by long, dark, horizontal legions on stored roots. The pathogen is soilborne and initial infection occurs before harvest. Late-harvested carrots may have higher amounts of infection. The fungus then develops in cold storage (4-6°C), especially when there is a film of moisture or very high humidity. Under high disease pressure, carrots can be dipped in fungicides or inorganic salts prior to storage. Washing carrots in water can also reduce inoculum clinging to root surfaces. Disinfestation of crates and other equipment minimizes disease development. Proper cold storage that avoids temperature fluctuations and condensation reduces disease and prevents dehydration. Removal of carrots from cold storage early can prevent losses.

Parsnip Blight (Pseudomonas marginalis)

Causes browning through the interior of the root. Practice at least a 2-year rotation.

Root and Crown Rot (Rhizoctonia solani)

Symptoms include dieback of foliage and brown sunken lesions on crowns. The pathogen has a wide host range, making crop rotation as a disease management tactic unsuccessful. Problems with this disease are more severe in organic soils and whenever undecomposed crop residue is present. Avoid crops such as alfalfa and legume cover crops which can increase disease risk. Wide spacing, weed control, and clean cultivation help reduce field infection by allowing soil to dry quickly. Avoid harvesting late in the season. 

• azoxystrobin (Quadris F): See label for in-furrow and drench rates; PHI 0d, REI 4h, Group 11. Rate varies for leaves and root/tuber vegetables. See label. 
• Bacillus amyloliquefaciens strain F727 (Stargus^OG): 2.0 to 4.0 qt/A; PHI 0d, REI 4h, Group BM02. See label for application methods. Apply preventatively in a minimum of 50 gallons of water/A.
• Bacillus subtilis Strain QST 713 (Minuet): 6.0 to 12.0 oz/A; PHI 0d, REI 4h, Group BM02. Soil-applied. See label for restrictions. 
• Trichoderma asperellum (ICC 012) plus T. gamsii (ICC 080), (Bio-tam 2.0^OG): See label for in-furrow, drench, and broadcast rates; REI 4h, Group BM02.

Sore Head (Itersonilia perplexans)

Occurs on parsnip only. Cankers form primarily on the crown and shoulders. Plant on raised beds in well-drained soil. The varieties 'Gladiator' and 'Andover' are somewhat resistant. Rotate parsnip with non-susceptible hosts and control wild Apiaceae plant hosts. Start with certified, disease-free seed. Protect roots by covering crowns and exposed upper roots with soil. Deep plow plant residue to reduce soilborne inoculum. Rarely occurs on young plants. Monitor fields near maturity and harvest affected fields early. Fungicide sprays are not effective.

White Mold (Sclerotinia sclerotiorum)

Fluffy white mycelium and black sclerotia distinguish this disease from other crown and root rots of carrots. The sclerotia can survive for many years on the soil. Rotate with small grains. Handle carrots carefully at harvest and washing. Use a post-harvest sanitizer and change wash water frequently to reduce spread of pathogens. Clean and disinfect storage containers and harvesting equipment between batches. Cool carrots quickly to remove field heat. Inspect and dispose of infested carrots. Maintain storage and shipping temperatures of 32°F and 95% relative humidity.

• penthiopyrad (Fontelis): 16.0 to 30.0 fl oz/A; PHI 0d, REI 12h, Group 7.
• thiabendazole (Mertect 340F): 41.0 fl oz/100 gal; REI 12h, Group 1. Dip carrots before storage. 
• fluazinam (Omega 500F): 16.0 fl oz/A; PHI 7d, REI 12h, Group 29.
• fluopyram plus difenoconazole (Luna Flex): 11.0 to 13.6 fl oz/A; PHI 1d, REI 12h, Groups 3 & 7. Carrot only. Do not make more than 2 sequential applications before rotation with non- Group 3 or 7 fungicide. 
• laminarim (Vacciplant): 14.0 to 22.0 fl oz/A; PHI 0d, REI 4h, Group P04. See label for application methods and restrictions. 
• Ulocladium oudemansii (U3 strain) (BotryStop WP^OG): 2.0 to 4.0 lbs/A; PHI 0d, REI 4h, Group BM02. Carrot only. Begin application when conditions are conducive to disease development. 

Aster Yellows

Remove inoculum sources by controlling Apiaceae weeds. Avoid fields near pastures or riverbanks that harbor susceptible vegetation. Destroy residues from susceptible crops immediately after harvest. Control the six-spotted leafhopper that carries the phytoplasma (see Carrot and Parsnip Insect Control).

Root-Knot Nematode (Meloidogyne spp.)

Low densities of root-knot nematodes before planting means susceptible crops will suffer damage. Monitor soils for nematode populations. Rotate with non-hosts such as cereals. Practice soil solarization or field fumigation in the fall. See Soil Fumigation Outdoors.

• Purpureocillium lilacinum strain 251 (Melocon (LC and WG)): See label for application rates; PHI 0d, REI 4h, Group NC. Treat just prior to planting.

Disease Control

NOTES: For the insecticides listed below, one product trade name and formulation is provided for each active ingredient (AI) as an example of rates, preharvest interval (PHI), restricted entry interval (REI), and special instructions. In many cases, there are other products available with the same AI. Please see Table 27 and Insecticides Alphabetically Listed by Trade Name for more information on these insecticides.

• The designation (Bee: L, M, or H) indicates a bee toxicity rating of low, moderate, or high. See the Protecting Honeybees and Native Pollinators section for more details.
• The symbol * indicates a product is a restricted use pesticide. See Pesticide Safety and Use for more details.
• The symbol ^OG indicates a product is listed by the Organic Materials Review Institute (OMRI) as approved for use in organic production. See Organic Certification section for more details.

Aster Leafhopper (Macrosteles quadralineatis)

Aster leafhopper is a minor pest in New England but a major pest in the Midwest. Although it inflicts very little direct feeding injury to carrots or parsnips, it is important because it vectors aster yellows. This mycoplasma-like pathogen causes distortion and discoloration of leaves and stunted, hairy, and bitter roots in both carrots and parsnips. Lettuce, celery, celeriac, parsley, corn, and potato are also susceptible. Aster leafhoppers also feed on cereal grains, especially oats, wheat, and barley, clover, and various weeds. The adults are small, less than 4 mm long, light green with grey wings, and have 6 pairs of black spots on the top and front of the head. Among vegetables, lettuce is the primary crop that is suitable for leafhopper reproduction. Eggs are laid in plant tissues, and the yellowish nymphs feed and develop into adults in 3-4 weeks. There are 3 generations per year in northern states. Aster leafhoppers migrate north annually from the southern US, and can arrive as early as May, sometimes already infected with the aster yellows pathogen. In northern states, they can also overwinter in the egg stage, on weeds or winter grains.

Unlike many insect-vectored viruses, adults or nymphs must feed for at least 2 hours to become infected with the aster yellows mycoplasma. This could occur on infected crops in a southern state before migration or on a local crop or weed. Weeds that may be infected include thistle, fleabane, wild lettuce, sow thistle, chicory, wild carrot, galinsoga, dandelion, plantain, and cinquefoil. There is an incubation period of 2-3 weeks inside the leafhopper; thereafter, it can transmit the pathogen for its lifetime. Transmission from the leafhopper to a non-infected plant also requires at least 2 hours of feeding. It takes 10-15 days for infected plants to show symptoms.

If aster yellows disease becomes a problem on your farm, plant tolerant or resistant varieties, which are available for carrot and lettuce. Control weed hosts and avoid growing susceptible crops in fields close to winter grains. Reflective or light-colored straw mulch effectively reduces aster yellows infection, and row cover prevents infection by keeping out leafhoppers. Cool, wet weather limits leafhopper activity and disease transmission. Monitor nearby grain fields or carrot crops in July and August using sweep nets. Thresholds widely used in the Midwest are based on the aster yellows index, which is the product of the percent infection of the leafhopper population (determined by testing) and the number of leafhoppers per 100 sweeps. At 2% infection, the threshold in carrots is 25 leafhoppers per 100 sweeps in susceptible varieties and 37 leafhoppers per 100 sweeps in tolerant varieties. In the absence of test results for % infection, assume 2%. It is important to control leafhoppers before infection takes place. Because several hours of feeding are required for the aster leafhopper to transmit aster yellows to a plant, disease suppression can be achieved by killing the vector before inoculation occurs.

• alpha-cypermethrin (Fastac* EC): 1.8 to 3.8 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A.
• beta-cyfluthrin (Baythroid*XL): 1.6 to 2.8 oz/A; PHI 0d, REI 12h, Bee: H, Group 3A. Carrot only. 
• carbaryl (Sevin XLR Plus): 1 to 2 qt/A; PHI 7d, REI 12h, Bee: H, Group 1A. Do not apply to crops in bloom. 
• deltamethrin (Delta Gold*): 1.5 to 2.4 oz/A; PHI 3d, REI 12h, Bee: H, Group 3A.
• esfenvalerate (Asana* XL): 5.8 to 9.6 oz/A; PHI 7d, REI 12h, Bee: H, Group 3A. Carrot only.
• flupyradifurone (Sivanto): 7 to 14 oz/A; PHI 7d, REI 4h, Bee: L, Group 4D.
• imidacloprid (Admire Pro): 0.31 to 0.74 oz/1,000 row ft or 4.4 to 10.5 oz/A; PHI 21d, REI 12h, Bee: H, Group 4A. Soil applications only.
• kaolin (Surround WPOG): 25 to 50 lb/A or 0.25 to 0.5 lb/gal; PHI 0d, REI 4h, Bee: L. Suppression and repellence only.
• malathion (Malathion 57 EC): 2 pt/A; PHI 7d, REI 24h, Bee: H, Group 1B. Carrot only.
• methomyl (Lannate* LV): 1.5 to 3 pt/A; PHI 1d, REI 48h, Bee: H, Group 1A. Carrot only.
• pyrethrin (PyGanic EC5.0^OG): 4.5 to 17 oz/A; 0.25 to 0.50 oz/gal, 3 gal/1000 sq ft in greenhouse for backpack sprayers; PHI 0d, REI 12h, Bee: M, Group 3A.
• sodium tetraborohydrate decahydrate (Prev-AM): 100 oz/100 gal; REI 12h, Bee: L, Group 25. Do not apply in midday sun or mix with copper, sulfur, or oils.
• sulfoxaflor (Transform WG): 1.5 to 2.75 oz/A; PHI 7d, REI 24h, Bees: H, Group 4C. Do not apply between 3 days prior to bloom and until after petal fall.
• thiamethoxam (Actara): 1.5 to 3 oz/A; PHI 7d, REI 12h, Bee: H, Group 4A.
• thiamethoxam (Platinum): 5 to 12 oz/A; REI 12h, Bee: H, Group 4A. Systemic insecticide used at seeding or within 24 hours of seeding as an in-furrow or narrow surface band with sufficient water for incorporation, or in drip irrigation application to the seed/seedling root zone during or after planting/transplanting operations.
• zeta-cypermethrin (Mustang*): 1.76 to 4 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A.

Carrot Rust Fly (Psila rosae)

Carrot rust fly feeds on many umbelliferous crops and weeds. Though it is considered principally a pest of carrots, it can also damage parsnips, celery, celeriac, parsley, and dill. Adults are slender flies, 4-5 mm long, with slightly iridescent wings, yellowish-brown head and legs, dark red eyes, and shiny black thorax and abdomen. Adult flies enter fields to oviposit and return to field edges daily. Clusters of 1-3 eggs are laid in the soil near the base of food plants. Larvae are milky-white to yellowish, without legs, tapered at the head with dark mouth hooks, and 6-9 mm when fully grown. Root feeding of hatching larvae may kill young plants or cause forked, stunted, or fibrous roots. Larvae burrow into the main root as they grow larger, then leave the root to form an oval brown pupa up to 10 cm deep in the soil. Sometimes larvae overwinter in fall carrot roots, but mainly pupa overwinter in the soil, and adults emerge in May and June. Cool, moist conditions favor adult emergence. Early-season carrots are susceptible to attack by this first flight, especially the earliest successions, as flies tend to select larger carrots to lay eggs. The summer generation of adult flies emerges in August and is active through September, causing damage to late or long-season carrots. Fall damage may increase in later harvests. The larva mines the root's surface, leaving trails and blotchy areas that develop a rusty color and render the root unmarketable. Wounds provide entry to plant pathogens. The foliage may become red or yellow. In carrots, the larval mines are mostly in the lower portion of the root, but in parsnips, they are in the upper portion. In celery, the larva may tunnel upward into the crown and stalks. Damage is often worst near sheltered field edges, with damage decreasing toward the center of the field.

Avoid leaving crops in the field over the winter, where they support overwintering larvae or attract spring egg-laying. Because adults are weak fliers and are limited to one crop family, crop rotation to a separate field is effective—plant carrots in open fields where wind protects them from adult flights if possible. The crop is most vulnerable around the edge of sheltered fields surrounded by woods. Row covers protect the crop from egg-laying. Intercropping with onion has been shown to reduce damage by carrot rust flies. Some varieties show partial resistance to rust flies. Stagger plantings to distribute risk, or if possible, time plantings to avoid the first and second flight periods. In the fall, harvest edges first, as these may have the most damage. Monitor flight with yellow sticky traps placed upright on a stake just above the canopy and several feet into the field; count flies twice weekly. Use multiple traps per field, especially along field edges that are sheltered from wind. Traps reflect population levels and indicate the beginning, peak and end of flight periods, and are used to time insecticides or determine when it is safe to remove row cover. In Quebec and Ontario, insecticides are recommended at thresholds of 0.1-0.2 flies per trap per day, although no registered products are available in New England. Where active periods coincide, sprays for carrot weevil may help control carrot rust flies.

Carrot Weevil (Listronotus oregonensis)

Carrot weevil attacks crops and weeds in the Umbelliferae family and can cause severe damage to parsley, dill, carrot, celery, and parsnip. Adult beetles are brown, less than 6 mm long, with the typical weevil ‘snout-like’ mouthparts. They overwinter in soil or plant debris near previous host crops. Although able to fly, they travel and invade fields mostly by walking. In spring, females lay eggs into holes that they gouge in petioles or tops of roots but only oviposit in plants that are older than the 4-leaf stage. Egg-laying starts at 234 growing degree days (GDD), using a base temperature of 44.6°F. Young larvae tunnel in stalks or roots and may kill young plants. Larvae tunnel downward as they grow. Tunnels are very pronounced and may be invaded by fungi. Unlike carrot rust fly, feeding damage by weevil larvae is limited to the upper third of the root. Pupation occurs in the soil, and new adults emerge after 1-2 weeks. There is generally 1 generation per year in New England. Weevils tend to be worse in organic soils. To prevent damage, rotate carrot and parsnip crops to new fields to escape overwintering adults. Delay planting until after eggs have been deposited (90% of oviposition is expected to be completed by 820 GDD). Carrot-baited traps (Mason jar, Boivin, or modified Boivin traps) deployed at field edges can detect incoming adults. Sampling roots is an effective way to estimate the population of larvae. Insecticide must be applied before egg-laying begins, so timing is important; GDD can be useful. Sprays targeting the adult beetles should be applied once or twice, 10-14 days apart, from the 1- to 3-leaf stage.

• alpha-cypermethrin (Fastac* EC): 1.8 to 3.8 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A.
• beta-cyfluthrin (Baythroid*XL): 2.8 oz/A; PHI 0d, REI 12h, Bee: H, Group 3A. Carrot only. 
• esfenvalerate (Asana*XL): 9.6 oz/A; PHI 7d, REI 12h, Bee: H, Group 3A. Begin treatment when weevils become active, and provide thorough spray coverage of crowns. Carrot only.
• Isaria fumosorosea Apopka Strain 97 (PFR-97 20% WDG^OG): 1 to 2 lb/A; PHI 0d, REI 4h, Bee: M, Group UN. Soil drench.
• malathion (Malathion 57 EC): 1 to 2 pt/A; PHI 7d, REI 24h, Bee: H, Group 1B. Parsnips only.
• oxamyl (Vydate* L): 2 to 4 pt/A; PHI 14d, REI 48h, Bee: H, Group 1A. Use as a soil-directed spray in 20 gal water/A. Must be incorporated into soil by water or mechanical means to a depth of at least 2". Carrot only.
• pyrethrin (PyGanic EC5.0^OG): 4.5 to 17 oz/A; 0.25 to 0.50 oz/gal, 3 gal/1000 sq ft in greenhouse for backpack sprayers; PHI 0d, REI 12h, Bee: M, Group 3A.

Cutworms

In carrots, cutworms feed on petioles, cutting them near the ground. One cutworm can destroy several plants in a single night. See cutworms in the Pepper and Tomato (Outdoor) sections for more information on black and variegated cutworms. Use spot treatments in affected areas.

• alpha-cypermethrin (Fastac* EC): 1.3 to 3.8 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A.
• Bacillus thuringiensis aizawai (XenTari^OG): 0.5 to 1.5 lb/A; PHI 0d, REI 4h, Bee: L, Group 11. Must be ingested; apply in evening or early morning, before larvae are actively feeding. Adherence and weather-fastness will improve with use of an approved spreader-sticker. Use high rate at cool temperatures. For resistance management, may be rotated with Bt kurstaki products (Dipel).
• Bacillus thuringiensis kurstaki (Dipel DF^OG): 0.5 to 2 lb/A; PHI 0d, REI 4h, Bee: L, Group 11. Must be ingested; apply in evening or early morning, before larvae are actively feeding. Adherence and weather-fastness will improve with use of an approved spreader-sticker. Use high rate at cool temperatures. For resistance management, may be rotated with Bt aizawai products (XenTari).
• beta-cyfluthrin (Baythroid* XL): 1.6 to 2.8 oz/A; PHI 0d, REI 12h, Bee: H, Group 3A. Carrot only. 
• bifenthrin (Brigade* 2EC): 5.1 to 6.4 oz/A; PHI 21d, REI 12h, Bee: H, Group 3A.
• carbaryl (Sevin XLR Plus): 1 to 2 qt/A; PHI 7d, REI 12h, Bee: H, Group 1A. Most effective on species that feed on upper portions of the plant.
• esfenvalerate (Asana* XL): 5.8 to 9.6 oz/A; PHI 7d, REI 12h, Bee: H, Group 3A. Carrot only.
• methomyl (Lannate* LV): 0.75 to 1.5 pt/A; PHI 1d, REI 48h, Bee: H, Group 1A. For variegated cutworm on carrot only.
• methoxyfenozide (Intrepid 2F): 8 to 16 oz/A; PHI 1d, REI 4h, Bee:L, Group 18. Suppression only.
• spinosad (Seduce^OG): 20 to 44 lb/A or 0.5 to1 lb/1000 sq ft.; PHI 3d, REI 4h, Bee: M, Group 5. Spread bait on soil around plants.
• zeta-cypermethrin (Mustang*): 1.28 to 4 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A.

Insect Control

NOTES: For the herbicides listed below, one product trade name and formulation is provided for each active ingredient along with preharvest interval (PHI), restricted entry interval (REI), resistance management group number, and example of rates and special instructions. In many cases, there are other products available with the same active ingredient. However, not all products with the same active ingredient are registered for use in a crop. Always check the product label to be sure that the crop is listed before using. 

Stale Seedbed

See Stale Seedbed Technique for information on the use of these herbicides or flaming.

• glyphosate (Roundup Power Max): PHI 14d, REI 4h, Group 9. 
• paraquat (Gramoxone SL 2.0*): REI 12h or 24h, Group 22. *Restricted use: Applicators must complete an EPA-approved paraquat training every 3 years: https://www.epa.gov/pesticide-worker-safety/paraquat-dichloride-training-certified-applicators.
• pelargonic acid (Scythe): PHI 1d, REI 12h, Group 0. 

Preemergent Herbicides (before weeds germinate)

• linuron (Lorox DF): PHI 14d, REI 24h, Group 5. Parsnip only. Apply 1.5-3 lbs/A per application, only 1 application allowed per year. Apply after planting but prior to crop emergence. Seed should be planted at least 1/2 inch deep. Lorox activity is higher on both weeds and parsnips if it has been cloudy for 3 or more days, so reduce the application under these conditions.
• pendimethalin (Prowl H2O): PHI 60d, REI 24h, Group 3. Carrot only. Apply up to 2.1 pt/A per application, only 1 application allowed per year. Can be applied to the soil surface within 2 days of seeding, before emergence of the crop or weeds, or at layby as a directed spray between the rows. Do not allow contact with the carrot plants or injury will occur. Do not apply over the top of emerged carrots.
• s-metolachlor (Dual Magnum): REI 24h, Group 15. MA, ME, and NH only. Carrot only. Make sure the label for your state is available for download before using this product. This is a restricted label available only to growers who apply through the website www.syngenta-us.com/labels/indemnified-label-login and agree to a waiver of liability. Main target weeds for this registration are galinsoga and yellow nutsedge. All label instructions will be supplied after the application for use is completed. 
• trifluaralin (Treflan HFP): REI 12h, Group 3. Carrot only. Apply 1-2 pts/A per application. Apply and incorporate before planting. Incorporated 2-3” into the final seedbed within 24 hours of application. Rate based on soil texture, percent organic matter, and rainfall.

Pre- and Postemergent Herbicides

• prometryn (Caparol 4L): PHI 30d, REI 12h or 48h, Group 5. Carrot only. Apply 2-4 pts/A per application, up to 3 applications allowed per year. Do not exceed 8 pt/A per crop cycle or 16 pt/A per year. Apply in a minimum of 20 gal/A of spray. Do not exceed 1 application before carrots emerge (up to 4 pt/A) plus 1 (up to 4 pt/A) or 2 applications after carrots emerge. Can be applied before carrots have emerged; activate with water through rainfall or irrigation. Can also be applied over the top of carrot, until the 6-leaf stage. Include a nonionic surfactant (0.5% v:v, 2 qt/100 gal of spray) or crop oil concentrate (1% v:v, 1 gallon/100 gal of spray). Do not apply when temperatures exceed 85°F.

Postemergent Herbicides (after weeds germinate)

• carfentrazone (Aim EC): REI 12h, Group 14. Apply 0.5-2 oz/A per application, multiple applications allowed per year. Do not exceed 6.1 oz/A per season. Apply to row middles of emerged crops with hooded sprayers to control emerged weeds. Prevent any spray from contacting the crop, or injury will occur. For best results, make application to actively growing weeds up to 4” tall and rosettes less than 3” across.
• clethodim (Select Max): PHI 30d, REI 24h, Group 1. Apply 9-16 oz/A per application, up to 4 applications per year, a minimum of 14 days apart. Do not exceed 64 oz/A per year. Apply to actively growing grasses. Add 0.25% v:v nonionic surfactant (1 qt/100 gal of spray). Can also be applied as a spot-spray by mixing 0.33-0.66% (0.44-0.85 oz/gal) Select Max and 0.25% v:v nonionic surfactant (0.33 oz/gal). Spray to wet, but do not allow runoff of spray solution.
• fluazifop (Fusilade DX): PHI 45d, REI 12h, Group 1. Carrot only. Apply up to 24 oz/A per application, up to 2 applications allowed per year, a minimum of 14 days apart. Do not exceed 48 oz/A per year. Apply to actively growing grasses (see product label for susceptible stage). Add either crop oil concentrate (0.5-1%, 0.5-1 gal/100 gal of spray) or nonionic surfactant (0.25-0.5%, 1-2 qt/100 gal of spray). 
• glyphosate (Roundup Power Max): PHI 14d, REI 4h, Group 9. Apply 10 oz to 3.1 qts/A per application, multiple applications allowed per year. Do not exceed 5 qts/A per year. Rate based on target weed species. Can be applied during fallow intervals, prior to planting or transplanting, at planting, or before crop has emerged. May cause injury when applied prior to transplanting or direct-seeding into plastic mulch. Remove residual product from plastic mulch with 0.5” of water through irrigation or rainfall prior to planting. Can also be applied with the wiper method using a 33% solution by volume. A maximum of 2 wiper applications allowed per year. The first application must be a minimum of 60 days before harvest and the second application must be a minimum of 7 days before harvest.
• linuron (Lorox DF): PHI 14d, REI 24h or 8d, Group 5. For carrots: Apply 1.5-3 lbs/A per application, multiple applications allowed per year. Do not exceed 4 lbs/A per year. Has not been tested on all varieties; crop tolerance should be verified before treating the entire field. Apply after carrots are at least 3” and before annual grasses exceed 2" tall and broadleaf weeds exceed 6" tall. Do not apply when the temperature exceeds 85°F as crop injury may result. Lorox activity is higher on both weeds and parsnips if it has been cloudy for 3 or more days, so reduce the application rate under these conditions. Do not apply Lorox as a tank mix with surfactant, nitrogen solution, or other pesticides.
• metribuzin (Metribuzin 75): PHI 60d, REI 12h, Group 5. Carrot only. Apply 0.3 lb/A per application, up to 2 applications allowed per year, a minimum of 3 weeks apart. Do not exceed 0.6 lb/A per year. Apply as a broadcast spray when carrots have 5-6 true leaves and weeds are less than 1" tall and 1" in diameter. Do not apply within 3 days of cool or wet weather or within 3 days of other sprays. Yellowing and burning of leaf tissue may occur. Has not been tested on all varieties; crop tolerance should be verified before treating the entire field. Fair on grasses.
• paraquat (Gramoxone SL 3.0*): REI 12h or 24h (application type), Group 22. Carrot only. Apply 1.3-2.7 pts/A per application, up to 3 applications allowed per year, a minimum of 7 days apart. Do not exceed 8 pts/A per year. Apply before, during, or after planting, but before emergence, as a banded or broadcast application. Apply in a minimum of 10 gal/A of spray. May be fatal if swallowed or inhaled. *Restricted use: Applicators must complete an EPA-approved paraquat training every 3 years: https://www.epa.gov/pesticide-worker-safety/paraquat-dichloride-training-certified-applicators.
• pelargonic acid (Scythe): PHI 1d, REI 12h, Group 0. Apply a 3-10% solution (3-10 gallons per 100 gallons of spray). Rate based on target weed species. Apply in 75-200 gal/A of spray or with a spot sprayer until foliage is wet but not to the point of runoff. Repeat applications as necessary. Can apply for vegetative burndown during site preparation, prior to crop emergence from soil, as a directed and shielded spray during crop growth taking care to avoid contact with foliage and green tissue of crops, or as a harvest aid and desiccant to remove crop leaves or ease harvest. 
• sethoxydim (Poast): PHI 30d carrots, 14d parsnips, REI 12h, Group 1. Apply 2.5 pt/A per application, multiple applications allowed per year, a minimum of 14 days apart. Do not exceed 5 pt/A per year for carrots or 2.5 pt/A per year for parsnips. Apply to actively growing grasses. Use with crop oil concentrate (2 pt/A) or methylated seed oil (1.5 pt/A). Crop oil can cause injury under hot and humid conditions. Can also be applied as a spot-spray by mixing 1-1.5% (1.3-1.9 oz/gal) Poast and 1% v:v crop oil concentrate (1.3 oz/gal). Spray to wet, but do not allow runoff of spray solution.

Weed Control