Disease Control

Brassicas - General Brassica Insect Control Brassica Weed Control Brassica Physiological Disorders

Alternaria Damping-off

Buy seed certified as disease-free or treat with hot water at 122°F for 25 minutes (see Hot Water Treatment of Seed in the Disease Management section). Brassica crop seed is susceptible to seed vigor loss from hot water treatment. Seed should be treated as close to planting as possible.

Alternaria Leaf Spot and Head Rot (Alternaria brassicicola, A. brassicae, and A. raphani)

Alternaria leaf spot and head rot are caused by at least three species of the fungus Alternaria and can be seedborne. Start with certified disease-free seed or treat seed with hot water. Practice a 3-year crop rotation with all brassica crops. Use proper plant and row spacing to ensure good air circulation. Irrigate in the morning. Avoid overhead irrigation if possible. Control weeds, especially those in the family Brassicaceae. Avoid working in fields when foliage is wet. Promptly incorporate plant debris after harvest, or mow if tillage is not possible in late fall crops. Varieties differ in susceptibility, but no resistant varieties are available. 

FRAC Group 3:

  • azoxystrobin + difenoconazole (Quadris Top): 12 to 14 fl oz/A; PHI 1d, REI 12h, Groups 11 & 3.
  • difenoconazole + cyprodinil (Inspire Super): 16 to 20 fl oz/A; PHI 7d, REI 12h, Groups 3 & 9. Apply in sufficient volume to achieve thorough coverage. 
  • flutriafol (Rhyme): 5 to 7 fl oz/A; PHI 7d, REI 12h.
  • triflumizole (Procure): 6 to 8 fl oz/A; PHI 1d, REI 12h.

FRAC Group 7:

  • boscalid (Endura): 6 to 9 oz/A; PHI 14d for leafy greens, 0d for head and stem vegetables, REI 12h. Maximum 2 applications per year
  • fluxapyroxad + pyraclostrobin (Priaxor Xemium): 6 to 8.2 fl. oz/A; PHI 3d, REI 12 h, Groups 7 & 11.
  • penthiopyrad (Fontelis): 14 to 30 fl oz/A; PHI 0d, REI 12h.
  • pydiflumetofen + fludioxonil (Miravis Prime): 11.4 fl oz/A; PHI 7d, REI 12h, Groups 7 & 12.

FRAC Group 9:

  • cyprodinil + fludioxonil (Switch 6.25 WG): 11 to 14 oz/A; PHI 7d, REI 12h, Groups 9 & 12.
  • difenoconazole + cyprodinil (Inspire Super): 16 to 20 fl oz/A; PHI 7d, REI 12h, Groups 3 & 9. Apply in sufficient volume to achieve thorough coverage. 

FRAC Group 11:

  • azoxystrobin (Quadris F): 6 to 15.5 fl oz/A; PHI 0d, REI 4h. Make no more than 2 consecutive applications before rotating to a non-Group 11 material. See label for list of allowed brassica crops.
  • azoxystrobin + difenoconazole (Quadris Top): 12 to 14 fl oz/A; PHI 1d, REI 12h, Groups 11 & 3.
  • fenamidone (Reason 500 SC): 8.2 fl oz/A; PHI 2d, REI 12h. Do not alternate with other Group 11 fungicides.
  • fluxapyroxad + pyraclostrobin (Priaxor Xemium): 6 to 8.2 fl. oz/A; PHI 3d, REI 12 h, Groups 7 & 11.
  • pyraclostrobin (Cabrio EG): 12 to 16 oz/A; PHI 0d, REI 12h.

FRAC Group 12:

  • pydiflumetofen + fludioxonil (Miravis Prime): 11.4 fl oz/A; PHI 7d, REI 12h, Groups 7 & 12

FRAC Group 19:

  • polyoxin D (OSO 5%SC): 6.5 to 13 fl oz/A; PHI 0d, REI 4h.

FRAC Group BM01:

  • botanical extract (EcoSwingOG): 1.5 to 2 pt/A; PHI 0d, REI 4h. For head and stem brassicas.
  • thyme oil (Guarda): 1 gal/29–159 gal water (0.625%-3.3% v/v); PHI 0d, REI 0h.

FRAC Group BM02:

  • Bacillus amyloliquefaciens strain D747 (Double Nickel 55OG): 0.25 to 3 lb/A (foliar); PHI 0d, REI 4h.
  • Pseudomonas chlororaphis strain AFS009 (HowlerOG): 2.5 to 7.5 lb/A; PHI 0d, REI 4h. Use preventatively. 

FRAC Group M01:

  • copper hydroxide (Kocide 3000): 0.5 to 0.75 lb/A; PHI 0d, REI 48h. Do not apply in a spray solution having a pH less than 6.5 or tank mix with Aliette. An OMRI-listed formulation is available (Kocide 3000-OOG).

FRAC Group M03:

  • mancozeb (Manzate Pro Stick): 1.6 to 2.1 lb/A; PHI 7d, REI 24h. Cabbage and broccoli only.

FRAC Group M05:

  • chlorothalonil (Bravo Weather Stik): 1.5 pt/A; PHI 7d, REI 12h.

FRAC Group NC:

  • potassium bicarbonate (MilStop SPOG): 1.25 to 5 lb/A; PHI 0d, REI 1h. See label for small volume application rates.

Black Leg (Phoma spp., aka Leptosphaeria spp.)

Symptoms of this fungal disease include grayish lesions with dark borders on leaves and stems. All brassica crops are susceptible. Rotate away from brassicas for at least 3 years. Start with certified, disease-free seed, or treat seed with hot water. Inspect seedlings for infection before planting out into the field. Use proper plant and row spacing to ensure good air circulation. Avoid overhead irrigation if possible. Control weeds, especially those in the family Brassicaceae. Avoid working in fields when foliage is wet. Promptly incorporate plant debris after harvest, or mow if tillage is not possible in late fall crops.

FRAC Group 2:

  • iprodione (Rovral 4F): 2 pt/A; PHI 0d, REI 24h. Broccoli only.

FRAC Group 7:

  • fluxapyroxad + pyraclostrobin (Priaxor Xemium): 6 to 8.2 fl. oz/A; PHI 3d, REI 12h, Groups 7 & 11.

FRAC Group 11:

  • fluxapyroxad + pyraclostrobin (Priaxor Xemium): 6 to 8.2 fl. oz/A; PHI 3d, REI 12 h, Groups 7 & 11
  • pyraclostrobin (Cabrio EG): 12 to 16 oz/A; PHI 0d, REI 12h.

FRAC Group M03:

  • thiram (Thiram 42-S): 8 lb/A; REI 24h, Group M03. Seed treatment.

FRAC Group NC:

  • potassium bicarbonate (MilStop SPOG): 1.25 to 5 lb/A; PHI 0d, REI 4h. See label for small volume application rates.

Black Rot (Xanthomonas campestris pv. campestris)

Symptoms of this bacterial disease include yellow to brown lesions, most often on the leaf margins. Some lesions will have a characteristic "V" shape and blackened veins. Practice a 3-year crop rotation with all brassica crops. Start with certified disease-free seed or treat seed with hot water. Use proper plant and row spacing to ensure good air circulation. Avoid overhead irrigation if possible. Control weeds, especially those in the family Brassicaceae. Avoid working in fields when foliage is wet. Promptly incorporate plant debris after harvest, or mow if tillage is not possible in late fall crops.

FRAC Group BM02:

  • Bacillus thuringiensis subsp. kurstaki strain ABTS-351 + methyl salicylate (Leap ES): 1 to 2 qt/A; PHI 0d, REI 12h, Group BM02. Cabbage only. 
  • Pseudomonas chlororaphis (HowlerOG): 2.5 to 7.5 lb/A. PHI 0d, REI 4h. Use preventatively. Not labeled for cauliflower.

FRAC Group M01:

  • copper hydroxide (Kocide 3000): 0.5 to 0.75 lb/A; PHI 0d, REI 48h. Do not apply in a spray solution having a pH less than 6.5 or tank mix with Aliette. An OMRI-listed formulation is available (Kocide 3000-OOG).
  • mancozeb + copper hydroxide (ManKocide): 1 to 1.75 lb/A; PHI 7d, REI 48h, Groups M03 & M01. Not labeled for cauliflower.

FRAC Groups M03:

  • mancozeb + copper hydroxide (ManKocide): 1 to 1.75 lb/A; PHI 7d, REI 48h, Groups M03 & M01. Not labeled for cauliflower.

FRAC Group P04:

  • laminarin (Vacciplant): 14 to 22 fl oz/A; PHI 0d, REI 4h.

FRAC Group P07:

  • acibenzolar-S-methyl (Actigard 50WG): 0.5 to 1 oz/A; PHI 7d, REI 12h. Suppression only.

Club Root (Plasmodiophora brassicae)

Initial symptoms include stunting, yellowing, and wilting. This disease is characterized by marked swelling and deformity of roots. There is currently no way to eliminate club root from infested soil, but the pathogen can be suppressed by practicing long crop rotation and increasing soil pH. Maintain soil at a pH of 7.0–7.2 by applying lime (maximum of 1000 lb/A per application). If club root is detected in a field, rotate out of brassicas in that field for 7 years. After the 7-year crop rotation, pH adjustment and fungicide applications may reduce the viable club root spores to below economic threshold levels of infection for many growing seasons to come. Cold, wet soils favor club root development and spore survival. Resistant varieties of some brassica crops are available. Prevent the movement of infested soil and irrigation water into uninfested fields.

FRAC Group 14:

  • PCNB (Blocker 4F): 3 pt to 5.62 gal/A; REI 12h. Rate dependent on application method; may be applied in transplant solution, or as band or broadcast application. 

FRAC Group 21:

  • cyazofamid (Ranman 400SC): 12.9 to 25.75 fl oz/A; PHI 0d, REI 12h. Tank mix with an organosilicone surfactant. Transplant soil drench or soil incorporation. 

FRAC Group 29:

  • fluazinam (Omega 500 F): 6.45 fl oz/100gal/A; PHI 7–50d (see label), REI 12–48h (see label). Transplant soil drench or incorporation.

FRAC Group BM02: 

  • Bacillus subtilis strain QST 713 (Serenade ASOOG): 2 to 4 fl oz/A; PHI 0d, REI 4h.

Downy Mildew (Hyaloperonospora brassicae)

Symptoms include angular yellow to orange lesions with dark speckling or veining on the upper sides of leaves, and crusty white sporulation on the upper and undersides of leaves. Resistant varieties of some brassica crops are available. Use proper plant and row spacing to ensure good air circulation. Avoid overhead irrigation if possible. Control weeds, especially those in the family Brassicaceae.

FRAC Group 4:

  • mefenoxam (Subdue MAXX): 0.25 to 0.5 pt/A; PHI 7d, REI 48h. Do not apply foliar sprays without a labeled tank-mix partner. For transplants grown for retail only.
  • mefenoxam + chlorothalonil (Ridomil Gold Bravo SC): 1.5 pt/A; PHI 7d, REI 48h, Groups 4 & M05. See label for plant-back restrictions and restrictions on certain brassicas.

FRAC Group 11:

  • azoxystrobin (Quadris F): 6 to 15.5 fl oz/A; PHI 0d, REI 4h.
  • fenamidone (Reason 500SC): 5.5 to 8.2 fl oz/A; PHI 2d, REI 12h. Do not alternate with other Group 11 fungicides.
  • pyraclostrobin (Cabrio EG): 12 to 16 oz/A; PHI 0d, REI 12h.

FRAC Group 21:

  • cyazofamid (Ranman 400SC): 2.75 fl oz/A; PHI 0d, REI 12h. Tank mix with an organosilicone surfactant. 

FRAC Group 29:

  • fluazinam (Omega 500F): 15.35 fl oz/A; PHI 7d, REI 12–48h. Cabbage and Chinese cabbage only. See label for REI details and restrictions. 

FRAC Group 40:

  • ametoctradin + dimethomorph (Zampro): 14 fl oz/A; PHI 0d, REI 12h, Groups 45 & 40.
  • dimethomorph (Forum): 6 fl oz/A; PHI 7d, REI 12h. Apply in combination with a labeled rate of another non-Group 40 fungicide.
  • mandipropamid (Revus): 5.5 to 8 fl oz/A; PHI 1d, REI 4h. Spreading/penetrating type adjuvant required.
  • oxathiapiprolin + mandipropamid (Orondis Ultra): 5.5 to 8 fl oz/A; PHI 1d, REI 4h, Groups 49 & 40. Begin foliar application prior to disease development. Use higher rate when disease is present. Spreading/penetrating adjuvant required.

FRAC Group 43:

  • fluopicolide (Presidio): 3 to 4 fl oz/A; PHI 2d, REI 12h. Tank-mix with a non-Group 43 fungicide.

FRAC Group 45:

  • ametoctradin + dimethomorph (Zampro): 14 fl oz/A; PHI 0d, REI 12h, Groups 45 & 40.

FRAC Group 49:

  • oxathiapiprolin + mandipropamid (Orondis Ultra): 5.5 to 8 fl oz/A; PHI 1d, REI 4h, Groups 49 & 40. Begin foliar application prior to disease development. Use higher rate when disease is present. Spreading/penetrating adjuvant required.

FRAC Group BM02:

  • Bacillus amyloliquefaciens strain D747 (Double Nickel 55OG): 0.125 to 1 lb/A (soil); PHI 0d, REI 4h.
  • Pseudomonas chlororaphis (Howler OG): 2.5 to 7.5 lb/A. PHI 0d, REI 4h. Use preventatively.

FRAC Group M01:

  • copper hydroxide (Kocide 3000): 0.5 to 0.75 lb/A; PHI 0d, REI 48h. Do not apply in a spray solution having a pH less than 6.5 or tank mix with Aliette. An OMRI-listed formulation is available (Kocide 3000-OOG).
  • mancozeb + copper hydroxide (ManKocide): 1 to 1.75 lb/A; PHI 7d, REI 48h, Groups M03 & M01. Broccoli and cabbage only.

FRAC Group M03:

  • mancozeb + copper hydroxide (ManKocide): 1 to 1.75 lb/A; PHI 7d, REI 48h, Groups M03 & M01. Broccoli and cabbage only.

FRAC Group M05:

  • chlorothalonil (Bravo Weather Stik): 1.5 pt/A; PHI 7d, REI 12h. See label for replant restrictions.
  • mefenoxam + chlorothalonil (Ridomil Gold Bravo SC): 1.5 pt/A; PHI 7d, REI 48h, Groups 4 & M05. See label for plant-back restrictions and restrictions on certain brassicas.

FRAC Group NC:

  • potassium bicarbonate (MilStop SPOG): 1.25 to 5 lb/100 gal; PHI 0d, REI 1h. See label for small volume application rates.

FRAC Group P01:

  • acibenzolar-S-methyl (Actigard 50WG): 0.5 to 1 oz/A; PHI 7d, REI 12h.

FRAC Group P05:

  • Reynoutria sachalinensis extract (RegaliaOG): 1 to 4 qt/A; PHI 0d, REI 4h. Apply to ensure thorough coverage.

FRAC Group P07:

  • fosetyl aluminum (Aliette WDG): 2 to 5 lb/A; PHI 3d, REI 24h. Do not mix with copper fungicides. Lower rates of Aliette can be used when tank-mixed with another fungicide labeled for downy mildew control.
  • phosphorous acid (Fosphite): 1 to 3 qt/100 gal/A; PHI 0d, REI 4h. Do not apply to plants that are heat- or moisture-stressed. Do not apply directly to plants treated with copper within 20-day interval.

Fusarium Yellows

This fungal pathogen is soil-borne and may also be seed-borne. Plant resistant varieties. Prevent the movement of infested soil to clean fields. Provide adequate fertility; potassium deficiency increases disease severity.

Seed Decay and Damping-off

Buy treated seed. Do not use treated seed for food, feed, or oil purposes.

FRAC Group 4: 

  • mefenoxam (Apron XL): 0.32 to 0.64 fl oz/lb seed; REI 48h. For Pythium damping-off protection. 

FRAC Group BM02: 

  • Bacillus amyloliquefaciens strain D747 (Double Nickel 55OG): 0.125 to 1 lb/A (soil); PHI 0d, REI 4h.
  • Streptomyces griseoviridis strain K61 (LALStopOG K61 WP, aka MycoStopOG):  See label for rate information; REI 4h. Rates vary by treatment method or unit of seed to be treated. 

FRAC Group M03:

  • thiram (Thiram 42-S): 8 fl oz/100 lb seed; REI 24h. Seed treatment.

Turnip Mosaic Virus

Turnip mosaic virus can infect most brassica crops, but it is most commonly seen in Chinese cabbage and bok choy. It is spread by many species of aphids in a nonpersistent manner; therefore, insecticides are of little or no value in controlling its spread. This virus survives the winter in perennial weeds. Symptoms vary with host and include yellow and/or necrotic spots, mosaic, leaf deformity, and interveinal chlorosis. Environmental conditions also affect symptom expression. Partially resistant cultivars include 'Nabyeng', 'Kongng', 'Tip Top', and 'Ta Feng'. These cultivars may be intolerant of heat.

Wire Stem, Crater Rot, and Head Rot (Rhizoctonia solani)

Diseases of brassica crops in this section caused by R. solani include wirestem and damping-off (seedlings), crater rot (root crops), and bottom or head rot (cabbage). Lesions caused by Rhizoctonia are brown to black and may be sunken. Rhizoctonia can be carried on the seeds of most brassica species and is ubiquitous in most soils, where it survives indefinitely. Start with certified, disease-free seed. Practice good sanitation in transplant production in order to avoid later need for fungicide drenches. Use treated seed for direct-seeding. Practices which encourage rapid germination and establishment limit disease development. Avoid planting transplants too deeply. Rotate crops. Do not plant susceptible brassicas in fields with undecomposed crop residues. No resistant varieties are available. Fungicide treatments in the field have limited effectiveness.

FRAC Group 14:

  • PCNB (Blocker 4F): 3 pt to 5.62 gal/A; REI 12h. Rate dependent on application method; may be applied in transplant solution, or as band or broadcast application. Note: R. solani referred to as Corticium solani on label.

FRAC Group 19:

  • polyoxin D (OSO 5%SC): 6.5 to 13 fl oz/A; PHI 0d, REI 4h.

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New England Vegetable Management Guide