Disease Control

NOTE: 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 25 and Fungicides and Bactericides Alphabetical Listing 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.

Anthracnose Leaf Curl (Colletotrichum fioriniae and C. nymphaeae)

Formerly known to be caused by Colletotrichum acutatum, the pathogen has now been identified to be caused by Colletotrichum fioriniae and C. nymphaeaeColletotrichum fioriniae also causes bitter rot in apples while C. nymphaeae also causes strawberry anthracnose. Common lambsquarters, redroot pigweed, yellow nutsedge, oakleaf goosefoot, and common groundsel all harbor celery anthracnose without clearly expressing symptoms. Symptoms on celery include curled leaves, occasional discoloration of leaf margins, twisted petioles, and lesions on petioles. Leaves remain green but often appear fan-like and curl downward.  Leaf curl is often the most prominent symptom observed and can resemble injury from growth regulator type (i.e. 2,4-D) herbicides. In advanced stages, the disease can resemble blackheart, the physiological disorder caused by low calcium assimilation. Celery leaf curl thrives under warm, wet conditions. Rapid growth occurs when temperatures are 77-86° F, with substantially more disease development at 86º F than 77° F. Temperatures as cool as 60° F will support fungal growth and spread, but field progression will be slow. This disease may be seedborne. Start with clean seed, flats, and growth medium. Scout plants twice a week for symptoms; remove and destroy affected plants. Removal of crop debris after harvest and plowing under crop residue will limit pathogen carry over from year to year. A 3- to 4-year crop rotation with non-host plants should be followed. Avoid working the fields when the plants are wet, work in fields with a history of the disease last, and power wash equipment between fields. Research has shown that the strobilurin fungicides are most effective. However, be careful to rotate as resistance can develop quickly in this group.

azoxystrobin (Quadris): 9.0 to 15.5 fl oz/A. PHI 0d, REI 4h, Group 11. Do not apply more than one application before alternating with a non-Group 11 fungicide.

Gliocladium catenulatum strain J1446 (PVentOG): PHI 0d, REI 4h. See label for instructions.

pyraclostrobin (Cabrio EG): 12-16 oz /A, PHI 0d, REI 12h , Group 11. Do not make more than 2 sequential applications of fungicides in this group, and no more than 64 oz per year.

pyraclostrobin plus boscalid (Pristine): 10.0 to 15.0 oz/A. PHI 0d, REI 12h, Groups 7 & 11.

Leaf Blight (Cercospora apii (Early Blight) or Septoria apicola (Late Blight)

The primary symptom of early blight is the occurrence of small yellow spots that are visible from both sides of the leaf. These spots may develop into larger lesions that become papery and tears. Gray, fuzzy fungus may be noticed in well-developed lesions. Favorable temperatures for early blight range from 60 to 86º F. This pathogen can be seedborne, can survive on celery residue, and spores can spread via wind and water splashing.

Small, yellow, circular spots on leaves are also symptoms of late blight in celery, which has similar symptoms to early blight in celery overall. One difference is that the small, round, and dark reproductive bodies of late blight, called pycnidia, can be seen in the center of lesions. This pathogen develops when temperatures are greater than 55º F, and particularly in wet conditions with temperatures over 70º F.

Use certified, disease-free seed or treat seed with hot water or fungicides. Practice careful sanitation in transplant greenhouses or rotate ground seedbeds. 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 where available. Apply fungicides based upon a disease forecasting system.

azoxystrobin (Quadris): 9.0 to 15.5 fl oz/A; PHI 0d, REI 4h, Group 11. Do not apply more than one application before alternating with a non-Group 11 fungicide.

azoxystrobin plus chlorothalonil (Quadris Opti): 2.4 to 3.7 pt/A; PHI 7d, REI 12h, Groups 11 & M5. See label for tank mix precautions.  

azoxystrobin plus propiconazole (Quilt): 14.0 fl oz/A; PHI 14d, REI 12h, Groups 11 & 3

chlorothalonil (Bravo Weather Stik): 2 to 3 pt/A; PHI 7d, REI 12h, Group M5.

copper hydroxide (Kocide 3000): 0.75 to 1.5 lb/A; PHI 0d, REI 48h, Group M1. Do not apply in a spray solution having a pH of less than 6.5 or tank mix with Aliette.

penthiopyrad (Fontelis): 14 to 24 oz/A; PHI 3d, REI 12h, Group 7.

propiconazole (Tilt): 4.0 fl oz/A; PHI 14d, REI 12h, Group 3.

pyraclostrobin plus boscalid (Pristine): 10.0 to 15.0 oz/A; PHI 0d, REI 12h, Groups 7 & 11.

trifloxystrobin (Flint): 2 to 3 oz/A; PHI 7d, REI 12h, Group 11. Do not make more than one application before alternating with a non-Group 11 fungicide.

Basal Stalk Rot (Rhizoctonia solani)

Sometimes called crater rot, or simply stalk rot. This pathogen causes symptoms on celery petioles where they are in contact with the soil, where reddish brown lesions form on either side of the petiole, and can become sunken. This pathogen is soilborne and infects many plants. It is favored by warm, humid/wet conditions, and can survive in soil as sclerotia for a long time.

A 2-year rotation is recommended to prevent buildup of disease-causing organisms.  Avoid crops such as alfalfa and legume cover crops which can increase disease risk.  Avoid cultivating late in the season. Maintain storage conditions at 50°F.

azoxystrobin (Quadris):  0.4 to 0.8 fl oz/1,000 row feet; PHI 0d, REI 4h, Group 11 (see label for clarification). Apply in a 7" band in-furrow or shortly after emergence.  After emergence, direct application to stem.

azoxystrobin plus chlorothalonil (Quadris Opti): 2.4 to 3.7 pt/A; PHI 7d, REI 12h, Groups 11 & M5. See label for tank mix precautions.  

chlorothalonil (Bravo Weather Stik): 2.0 to 3.0 pt/A; PHI 7d, REI 12h, Group M5.

polyoxin D (OSO 5%SC): 3.75 to 13.0 fl oz/A; PHI 0d, REI 4h, Group 19.

Pink Rot (Sclerotinia sclerotiorum)

Pink rot in celery is caused by the same pathogen than causes white mold in beans and peas. This pathogen can infect celery at any developmental stage, but is most commonly seen in near harvest. Initially brown lesions on the lower portion of petioles that turn watery and pink in color is the most characteristic symptom. Lesions can contain white mycelia and/or hardened black sclerotia. Severely infected plants may totally collapse. Do not plant seed contaminated with sclerotia or plant into severely infested fields. Irrigate in the morning or with subsurface drip systems to promote drier soil. Rotate with non-hosts. Soil sterilization with chemicals, heat, or steam can reduce sclerotia in the soil.

Bacillus amyloliquefaciens F727 (StargusOG): 2 to 4 qt/A; PHI 0d, REI 4h, Group 44. Apply preventatively in a minimum of 50 gallons of water/A.

boscalid (Endura): 8.0 to 9.0 oz/A; PHI 0d, REI 12h, Group 7.

chlorothalonil (Bravo Weather Stik): 3.0 pt/A; PHI 7d, REI 12h, Group M5. For disease suppression.

Coniothyrium minitans (Contans WGOG): 1.0 to 4.0 lb/A in 20-50 gal water; REI 4h, Group not applicable. Spray on soil surface and incorporate into top 2" soil. Apply in fall or 3-4 months prior to planting.

cyprodonil + fludioxonil (Switch): 11.0 to14.0 oz/A; PHI 0d, REI 12h, Groups 9 & 12. Make first application at thinning and once more two weeks later.

Ulocladium oudemansii (BotryStopOG): 2.0 to 4.o lbs/A; REI 4h, Group not applicable. Begin application when conditions are conducive to disease development.