Cause Cercospora melongenae, a fungus that survives at least one year in infected plant debris or in soil. Wet leaves and a high relative humidity favor disease development.
Symptoms Leaf spots appear in oldest leaves first. Leaf spots on eggplant are small, chlorotic circular-to-oval spots that turn gray to brown on the upper leaf surface and light-brown on the lower leaf surface. As disease progresses, concentric rings of diseased tissues may develop with sporulation in the center of spots. Lesions may dry out, leading to cracks in the tissue and the development of shot holes where the tissue in the center of spots falls out. Eggplant fruit are not attacked but yields can be reduced under severe foliar infections.
Cultural control
- Use pathogen-free transplants.
- Minimize periods of high relative humidity and free moisture on leaves through the use of drip, rather than overhead irrigation, controlling weeds, increasing plant spacing, and avoiding overirrigation.
- Bury infected crop debris or remove and destroy infected leaves.
Chemical control
- Aprovia Top (Group 7 + 3) at 10.5 to 13.5 fl oz/A on 7- to 10-day intervals. Do not make more than two (2) sequential applications before alternating to a labeled fungicide with a different mode of action. Preharvest interval is 0 days. 12-hr reentry.
- Bravo Weather Stik (Group M5) at 1.5 pints/A or Bravo Ultrex at 1.4 lb/A on 7- to 10-day intervals. Preharvest interval is 3 days. 12-hr reentry
- Cabrio EG (Group 11) at 8 to 12 oz/A or 8 to 12 oz/100 gal of spray volume (dilute) on 7- to 14-day intervals is labeled for other diseases of eggplant and should help with Cercospora leaf spot. Do not make more than one application of Cabrio EG or other Group 11 fungicide before alternating to a labeled fungicide with a different mode of action. Preharvest interval is 0 days. 12-hr reentry.
- Copper products are not recommended as stand-alone materials.
- 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
- Echo 720 (Group M5) at 1.5 pints/A on 7- to 10-day intervals. Preharvest interval is 3 days. 12-hr reentry.
- Endura (Group 7) at 2.5 to 3.5 oz/A on 7- to 14-day intervals is labeled for other diseases of eggplant and should help with Cercospora leaf spot. Do not make more than two (2) sequential applications of Endura before alternating to a labeled fungicide with a different mode of action. Preharvest interval is 0 days. 12-hr reentry.
- Orondis Opti (Group M5 + 49) at 1.75 to 2.5 pints/A on 7- to 10-day intervals. Do not apply more than two (2) sequential applications. Preharvest interval is 3 days. 12-hr reentry.
- Quadris Top (Group 3+11) at 8 to 14 fl oz/A on 7- to 10-day intervals. Preharvest interval is 0 days. 12-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