Cause Colletotrichum coccodes, C. dematium, and C. gloeosporioides cause anthracnose on tomato; C. coccodes is the most prevalent, but anthracnose is not common in the Pacific Northwest. The fungus overwinters as microsclerotia, often in association with plant debris. Solanaceous crops and weeds are all hosts. Seed may also be infected. Free moisture and mild temperatures are conducive for disease with 68°F to 76°F being optimum for infections. Wounding of the plant by mechanical injury or other pathogens facilitates infection by C. coccodes.
Microsclerotia can survive several years in soil, producing conidia during moist conditions that also favor infection. Fungi may attack fruit that touch the soil or may be splashed on fruit or foliage. In wet weather, spores produced in spots on fruit are splashed by rain or spread by pickers to infect other fruit. Overhead irrigation favors disease spread. Infection is favored by free moisture and temperatures between 50°F and 86°F, with 68°F to 76°F being optimum for infection.
Symptoms Spotting on fruit is the major symptom; however, leaves, stems, or roots also may be infected. Fruit may be infected when green and small but show no evident spotting until ripening. Fruit becomes increasingly susceptible as it approaches maturity. Root infection is primarily in greenhouses and becomes evident as fruit begins to ripen.
At first, infected fruit have small, slightly sunken, circular spots. Spots grow to about 0.5 inch in diameter, darker with concentric rings, and more concave. Centers are usually tan and may have numerous dark specks (microsclerotia). Flesh beneath a lesion can be a lighter color than surrounding tissue. In warm weather, the spot soon penetrates into the fruit, which becomes worthless.
If leaves are infected, small, circular, dark areas of dead tissue, often surrounded by yellow halos, are evident. The oldest leaves are the most commonly infected. Roots may have brown lesions and will contain microsclerotia as they rot. Because of root damage, diseased plants are easily pulled from the soil.
Cultural control
- Use pathogen-free seed.
- Practice at least three-year rotations with a non-solanaceous plant.
- Control night shades and other solanaceous weeds throughout the crop rotation period.
- Irrigate only as needed, never in excess. Use drip rather than overhead irrigation.
- Use mulches, and stake plants.
- Remove and destroy infected fruit (prevents buildup of soil population) or bury infected crop residues.
- In greenhouse production use pathogen-free soil, prevent root injury, and avoid closed-recirculation irrigation-fertilization systems.
Chemical control
- Chlorothalonil formulations (Group M5).
- Bravo Ultrex at 1.8 to 2.6 lb/A at 7- to 14-day intervals. 12-hr reentry.
- Echo 720 at 2 to 3 pints/A on 7- to 14-day intervals beginning at fruit set. Preharvest interval is 0 days. 12-hr reentry.
- Copper (Group M1) products are not recommended as stand-alone materials.
- Badge SC at 0.75 to 1.8 pints/A and 0.5 to 1.5 Tbsp/1,000 sq ft in greenhouses on 3- to 10-day intervals. Preharvest interval is 0 days. 24-hr reentry for greenhouse use; 48-hr reentry for all other applications.
- Cueva at 0.5 to 2 gal/100 gal water on 7- to 10-day intervals. May be applied on the day of harvest. 4-hr reentry. O
- Cuprofix Ultra 40 Disperss at 1.25 to 3 lb/A on 5- to 10-day intervals. 48-hr reentry.
- Nu-Cop 50 DF at 1 lb/A for processing tomato and 3.2 lb/A for fresh market tomato on 3- to 10-day intervals. 48-hr reentry. O
- Previsto at 1 to 2 quarts/A on 5- to 10-day intervals. 48-hr reentry. O
- Mettle 125 ME (Group 3) at 6 to 8 fl oz/A on 7- to 14-day intervals. Application can be made the day of harvest. 12-hr reentry.
- OSO 5% SC (Group 19) at 3.75 to 13 fl oz/A on 7- to 14-day intervals will suppress disease. Can be applied the day of harvest. 4-hr reentry O.
- Phosphorous acid-based products (Group P7) available.
- Fosphite at 1 to 3 quarts in 100 gal water on 2- to 3-week intervals. 4-hr reentry.
- Regalia (Group P5) at 1 to 4 quarts/A plus another fungicide on 7- to 10-day intervals. Does not benefit from the addition of an adjuvant. Preharvest interval is 0 days. 4-hr reentry. O
- Rhyme (Group 3) at 5 to 7 fl oz/A. Alternate or tank-mix with a non-Group 3 fungicide for resistance management. Preharvest interval is 0 days. 12-hr reentry.
- Strobilurin formulations (Group 11) are labeled for use. Do not make more than one (1) application of a Group 11 fungicide before alternating to a labeled fungicide with a different mode of action.
- Cabrio EG at 8 to 12 oz/A or at 8 to 12 oz/100 gal spray volume (dilute). Preharvest interval is 0 days. 12-hr reentry.
- Quadris Flowable at 5 to 6.2 fl oz/A. May be applied the day of harvest. 4-hr reentry.
- Trilogy at 0.5% to 1%. Not labeled for use in Oregon. Do not use above 90°F or when plants are under heat or moisture stress. Do not use when foliage is wet as good coverage is essential. Poor control as a stand-alone product. 4-hr reentry. O
- Premixes of fungicides are available and offer ease for fungicide resistance management. Do not make more than one (1) application of a Group 11 fungicide before alternating to a labeled fungicide with a different mode of action; for other fungicide groups apply no more than two (2) sequential applications alternating with another fungicide with a different mode of action.
- Aprovia Top (Group 7 + 3) at 10.5 to 13.5 fl oz/A on 7- to 14-day intervals. Can be applied the day of harvest. 12-hr reentry.
- Dexter Max (Group M3 + 11) at 0.8 to 1.1 lb/A on 7- to 10-day intervals. Preharvest interval is 5 days. 24-hr reentry.
- Dexter Xcel (Group M3 + 11 + 3) at 36 fl oz/A on 7- to 10-day intervals. Preharvest interval is 7 days. 24-hr reentry.
- Inspire Super (Group 3 + 9) at 16 to 20 fl oz/A on 7- to 10-day intervals. Do not make more than one (1) application before alternating to a labeled fungicide with a different mode of action (non-Group 3 or 9). Preharvest interval is 0 day. 12-hr reentry.
- ManKocide (Group M1 + M3) at 2.5 to 5 lb/A on 7- to 10-day intervals. Under moderate to severe disease pressure use the higher rate on 3- to 7- day intervals. Do not apply within 5 days of harvest. 48-hr reentry.
- Orondis Opti (Group M5 + 49) at 1.75 to 2.5 pints/A on 7- to 14-day intervals. Preharvest interval is 0 days. 12-hr reentry.
- Priaxor Xemium Brand (Group 7 + 11) at 4 to 8 fl oz/A on 7- to 14-day intervals. Preharvest interval is 0 day. 12-hr reentry.
- Quadris Opti (Group 11 + M5) at 1.6 pints/A or Quadris Top (Group 11 + 3) at 8 fl oz/A. Do not apply until 21 days after transplanting or 35 days after seeding. Adjuvants should not be used. Preharvest interval is 0 days. 12-hr reentry.
- Revus Top (Group 3 + 40) at 5.5 to 7 fl oz/A on 7- to 10-day intervals. Do not use on varieties in which mature tomatoes will be less than 2 inches. Preharvest interval is 1 day. 12-hr reentry.
- Tanos (Group 11 + 27) at 8 oz/A on 5- to 7-day intervals. Must be tank-mixed with an appropriate fungicide with a different mode of action (non-Group 11 or 27). Do not apply within 3 days of harvest. 12-hr reentry.
Reference Jones, J.B., Jones, J.P., Stall, R.E., and Zitter, T.A. 1991. Compendium of Tomato Diseases. St. Paul, MN: APS Press.