Disease Control

Spinach - General Spinach Insect Control Spinach Weed Control

Cladosporium Leaf Spot (Cladosporium variabile)

Cladosporium leaf spot, caused by Cladosporium variabile, was previously considered to be of minor importance in spinach crops but can be severe in spinach seed production and has become a widespread problem in winter high tunnel production. Symptoms begin on the foliage as pale/tan lesions that develop olive-green spores. The most conducive environment for disease development is cool and moist with temperatures between 59ºF–68ºF and relative humidity above 80%; however, the fungus can grow under a wide range of temperatures, 41ºF–86ºF. Spinach seeds carry the fungus, but it has not been determined whether the disease is transmitted via contaminated seed to soil or seedlings. It is not known how long the fungus can survive on spinach residues in soil or in weed hosts. C. variabile has been recovered from dried leaves and seed stocks up to 8 years old. Cultural controls mainly rely on sanitation—the removal of infected plants, spinach debris, spinach volunteers, and unused seed. Start with certified, disease-free seed or treat seed with hot water or bleach to reduce seedborne inoculum. Avoid covering wet plants with row covers. Cultivar susceptibility varies but is rarely reported by seed producers or distributors.

FRAC Group P06:

  • Bacillus mycoides isolate J (LifeGard WGOG): 1 to 4.5 oz/A; PHI 0d, REI 4h. Apply at first true leaf stage or after thinning. 

Cucumber Mosaic Virus (CMV)

CMV is found worldwide and infects over eight hundred crops and weed hosts. Symptoms include mosaic, mottling, stunting, and leaf distortion. This disease is transmitted by aphids in a nonpersistent manner; insecticides are of no value in controlling this disease. Start with virus-free seed. Eliminate weeds. Grow resistant varieties such as Winter Bloomsdale and Renegade.

Downy Mildew (Peronospora effusa formerly, P. farinosa f. sp. spinacea)

Spinach downy mildew (SDM) is considered the most important disease of spinach and is favored by cool, moist conditions. The pathogen is host-specific to spinach and will not survive without a living host. Incidence of the disease appears to be increasing due to the increased use of high tunnels for winter spinach production. The potential overlap of field spinach and high tunnel spinach can create a “green bridge” for the disease, allowing the pathogen to transfer between fields and high tunnels. SDM begins as irregular yellow patches on upper leaf surfaces with purplish-gray sporulation on the undersides of leaves. Lesions may eventually dry out and turn brown. There are currently 19 numbered races of SDM, along with numerous "novel" races, and new races can emerge every year. SDM management relies on resistant cultivars, as well as managing relative humidity and leaf wetness. Select cultivars with resistance to races 1–19, if possible, and grow multiple cultivars that do not share the same gaps in resistance. Once infected, there is little that can be done to manage SDM. The pathogen can produce long-lived resting spores, called oospores, which can potentially survive in the soil without a living host; however, the role of oospores in season-to-season survival in New England is currently unknown. Rotate out of spinach for at least 2 years. Manage weeds.

FRAC Group 4:

  • mefenoxam (Ridomil Gold SL): 0.25 pt/A; PHI 21d, REI 48h. Do not apply to greenhouse or high tunnel crops. 

FRAC Group 7:

  • fluxapyroxad + pyraclostrobin (Merivon Xemium): 6 to 11 fl oz/A; PHI 1d, REI 12h, Groups 7 & 11. Suppression only. Do not apply as tank mix with other pesticides or anything other than water. Not for greenhouse or high tunnel use. 

FRAC Group 11:

  • azoxystrobin (Quadris F): 12 to 15.5 fl oz/A; PHI 0d, REI 4h. Rotate with a non-Group 11 fungicide. Phytotoxicity may occur. Proceed with caution when using tank mixes. Not for greenhouse or high tunnel use.
  • famoxadone + cymoxanil (Tanos): 8 to 10 oz/A; PHI 1d, REI 12h, Groups 11 & 27. Must be tank mixed with an appropriate contact fungicide from a different FRAC Group. Do not alternate or tank mix with other Group 11 fungicides.
  • fenamidone (Reason 500SC): 5.5 to 8.2 fl oz/A; PHI 2d, REI 12h. Do not make more than one application before alternating with a fungicide from a different resistance management group. Not for greenhouse or high tunnel use. 
  • fluxapyroxad + pyraclostrobin (Merivon Xemium): 6 to 11 fl oz/A; PHI 1d, REI 12h, Groups 7 & 11. Suppression only. Do not apply as tank mix with other pesticides or anything other than water. Not for greenhouse or high tunnel use. 
  • pyraclostrobin (Cabrio EG): 12 to 16 oz/A; PHI 0d, REI 12h. May cause leaf injury. Do not apply with anything other than water. Not for greenhouse or high tunnel use. 

FRAC Group 21:

  • cyazofamid (Ranman 400SC): 2.75 fl oz/A; PHI 0d, REI 12h. Do not plant other crops not registered for this product within 30 days of the last application. 

FRAC Group 27:

  • cymoxanil (Curzate 60DF): 5 oz/A; PHI 1d, REI 12h. Use only in combination with a protectant fungicide. See label for crop rotation restrictions.
  • famoxadone + cymoxanil (Tanos): 8 to 10 oz/A; PHI 1d, REI 12h, Groups 11 & 27. Must be tank mixed with an appropriate contact fungicide from a different FRAC Group. Do not alternate or tank mix with other Group 11 fungicides.

FRAC Group 40:

  • ametoctradin + dimethomorph (Zampro): 14 fl oz/A; PHI 0d, REI 12h, Groups 45 & 40. Not for greenhouse or high tunnel use. 
  • mandipropamid (Revus): 5.5 to 8 fl oz/A; PHI 1d, REI 4h. Addition of adjuvant is recommended. 

FRAC Group 43:

  • fluopicolide (Presidio 4SC): 3 to 4 fl oz/A; PHI 2d, REI 12h. Must be used in a tank mix with a fungicide with a different mode of action. Not for greenhouse or high tunnel use. 

FRAC Group 45:

  • ametoctradin + dimethomorph (Zampro): 14 fl oz/A; PHI 0d, REI 12h, Groups 45 & 40. Not for greenhouse or high tunnel use. 

FRAC Group 49:

  • oxathiapiprolin (Orondis Gold 200): 1.2 to 2.4 fl oz/A (foliar), 4.8 to 9.6 fl oz/A (soil application); PHI 0d, REI 4h. Apply at planting. Not for greenhouse or high tunnel use. 
  • oxathiapiprolin + mandipropamid (Orondis Ultra): 5.5 to 8 fl oz/A (foliar); PHI 1d, REI 4h, Groups 49 & 40. Apply with an adjuvant. Not for greenhouse or high tunnel use. 

FRAC Group BM02:

  • Bacillus amyloliquefaciens strain D747 (Double Nickel LCOG): 0.25 to 3 lb/A (foliar); PHI 0d, REI 4h.

FRAC Group M01:

  • copper hydroxide (Kocide 3000): 0.75 to 1.25 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). Flecking may occur on spinach leaves.
  • copper oxychloride + copper hydroxide (Badge X2OG): 0.75 to 1.25 lb/A; PHI 0d, REI 24h (greenhouse), 48h (field). Flecking may occur on spinach leaves. 

FRAC Group P01:

  • acibenzolar-S-methyl (Actigard 50WG): 0.5 to 0.75 oz/A; PHI 7d, REI 12h. Do not apply to plants that are stressed or when extended cold or/and cloudy conditions are expected. May cause crop injury to young seedlings.

FRAC Group P07:

  • fosetyl aluminum (Aliette WDG): 2 to 5 lb/A; PHI 3d, REI 24h. Lower rate of 2–3 lb/A may be used when tank mixed with another fungicide labeled for downy mildew (do not mix with copper). 
  • phosphorous acid (Fosphite): 1 to 3 qt/20 gal foliar; PHI 0d, REI 4h. Do not apply to plants that are heat- or moisture-stressed or recently treated with copper products.

Seed Decay

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

  • azoxystrobin (Dynasty): 0.10 to 3.75 fl oz/100 lb seed; REI 14h, Group 11. 
  • mefenoxam (Apron XL): 0.085 to 0.64 fl oz/100 lb seed; REI 48h, Group 4. For Pythium damping-off protection. Not for greenhouse or high tunnel use.
  • thiram (Thiram 42-S): 8 fl oz/100 lb seed; REI 24h, Group M03.
  • Streptomyces sp. strain K61 (MycoStopOG): 0.04 to 4 oz/lb seed; REI 4h, Group BM02. 

Stemphylium Leaf Spot (Stemphylium botryosum)

This relatively new disease of spinach was first detected in California in 2001 and has since become a problem in high tunnel production. In the field, the disease spreads slowly and damage is limited. Symptoms include light gray/tan leaf spots 1/16"–1/2" in diameter, with larger spots being more irregular. As spots age, they dry up and become papery in texture. The pathogen is known to be seedborne. Cultural controls mainly rely on sanitation—the removal of infected plants, spinach debris, spinach volunteers, and unused seed. Do not cover wet plants with row covers. Start with certified, disease-free seed or treat seed with hot water or bleach to reduce seedborne inoculum.

FRAC Group 7:

  • fludioxonil + pydiflumetofen (Miravis Prime): 9.2 to 13.4 fl oz/A; PHI 0d, REI 12h, Groups 12 & 7.

FRAC Group 12:

  • fludioxonil + pydiflumetofen (Miravis Prime): 9.2 to 13.4 fl oz/A; PHI 0d, REI 12h, Groups 12 & 7.

FRAC Group P06:

  • Bacillus mycoides isolate J (LifeGard WGOG): 1 to 4.5 oz/100 gal water/A; PHI 0d, REI 4h.

White Rust (Albugo occidentalis)

White rust is a very damaging disease of spinach that is found only east of the Rocky Mountains in the U.S. Symptoms begin as yellow spots on the upper leaf surface, while small, white pustules form on the undersides of leaves. The pathogen is not a true fungus but rather an oomycete like the downy mildews. It produces oospores which can persist in soil and on contaminated seed for several years. Plant resistant cultivars and practice a 3-year crop rotation. Manage weeds. Apply preplant and foliar fungicides.

FRAC Group 4:

  • mefenoxam (Ridomil Gold SL): 0.25 pt/A; PHI 21d, REI 48h. Shank application 21 days after planting or after the first cutting for control of white rust. Not for greenhouse or high tunnel use. 

FRAC Group 11:

  • azoxystrobin (Quadris F): 6 to 15.5 fl oz/A; PHI 0d, REI 4h. Quadris may be phytotoxic to spinach. Not for greenhouse or high tunnel use.
  • amoxadone + cymoxanil (Tanos): 8 to 10 oz/A; PHI 1d, REI 12h, Groups 11 & 27. Must be tank mixed with an appropriate contact fungicide from a different FRAC Group. Do not alternate or tank mix with other Group 11 fungicides.
  • fenamidone (Reason 500SC): 5.5 to 8.2 fl oz/A; PHI 2d, REI 12h. Not for greenhouse or high tunnel use. 
  • pyraclostrobin (Cabrio EG): 8 to 12 oz/A. PHI 0d, REI 12h. May cause crop injury under certain conditions. Do not apply as tank mix with anything other than water. Not for greenhouse or high tunnel use. 

FRAC Group 21:

  • cyazofamid (Ranman 400SC): 2.75 fl oz/A; PHI 0d, REI 12h.

FRAC Group 27:

  • famoxadone + cymoxanil (Tanos): 8 to 10 oz/A; PHI 1d, REI 12h, Groups 11 & 27. Must be tank mixed with an appropriate contact fungicide from a different FRAC Group. Do not alternate or tank mix with other Group 11 fungicides.

FRAC Group 43:

  • fluopicolide (Presidio 4SC): 3 to 4 fl oz/A; PHI 2d, REI 12h. Must be used in a tank mix with a fungicide from a different FRAC Group. Not for greenhouse or high tunnel use. 

FRAC Group M01:

  • copper hydroxide (Kocide 3000): 0.75 to 1.25 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). Flecking may occur on spinach leaves.
  • copper oxychloride + copper hydroxide (Badge X2OG): 0.75 to 1.25 lb/A; PHI 0d, REI 48h. Flecking may occur.

FRAC Group P01:

  • acibenzolar-S-methyl (Actigard 50WG): 0.5 to 0.75 oz/A; PHI 7d, REI 12. Do not apply to plants that are stressed or when extended cold or/and cloudy conditions are expected. May cause crop injury to young seedlings. 

FRAC Group P04:

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

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New England Vegetable Management Guide