Pacific Northwest 1998 An Online Guide to Plant Disease Control

FactSheets offer superior print quality for the page you are currently viewing. Using Microsoft's Internet Explorer has given best printing results.
Glossary
Guide Home
Search

OSU Extension Office
 
Cucumber (Cucumis sativus) -- Powdery Mildew
 
Cause: The fungi Erysiphe cichoracearum and Sphaerotheca fuliginea. Warm temperatures and dew formation in summer favor disease development.
Symptoms: First, tiny white superficial spots appear on leaves and stem. Spots become powdery white and expand to cover all portions of the plant. Sometimes the mycelium becomes covered with small black structures (chasmothecia) about the size of a pinhead. Usually the disease is in scattered spots in the field.
Cultivar Resistance: The cultivars 'Dasher II', 'Turbo', 'Calypso', 'Cross Country', 'Flurry', 'Royal', 'Regal', 'Quest', 'Cherokee', 'Marketmore', and 'Pioneer' are resistant to powdery mildew.
Cultural control: A 2-year rotation out of cucurbits is helpful.
Chemical control: Usually the disease is not severe enough to warrant a spray program.
  1. Cabrio EG at 12 to 16 oz/A on 7- to 14-day intervals. Do not make more than one (1) application of Cabrio EG or other Group 11 fungicide before alternating to a labeled fungicide with a different mode of action. Do not tank-mix with malathion, Kelthane, Thiodan, Phaser, Lannate, Lorsban, M-Pede, or Botran or injury may result. Preharvest interval is 0 days. 12-hr reentry.
  2. Cuprofix Ultra 40D at 1.25 to 2 lb/A on 5- to 7-day intervals. 12-hr reentry.
  3. Flint at 1.5 to 2 oz/A on 7- to 14-day intervals. Do not make more than one (1) application of Flint or other Group 11 fungicide before alternating to a labeled fungicide with a different mode of action. 12-hr reentry.
  4. Folicur 3.6F at 4 to 6 fl oz/A on 10- to 14-day intervals. Do not apply within 7 days of harvest. 12-hr reentry.
  5. JMS Stylet-Oil at 3 to 6 quarts/100 gal water. Do not spray if temperature is below 50°F, above 90°F, or when plants are under heat or moisture stress. 4-hr reentry.
  6. Kaligreen at 2.5 to 5 lb/A on 7- to 10-day intervals. Might be used to supplement a normal program when powdery mildew is first observed. May be applied up to the day before harvest. 4-hr reentry.
  7. Kop-R-Spray at 2 to 3 teaspoons/gal water.
  8. Kocide 2000 at 1 to 2.25 lb/A or Kocide 3000 at 0.5 to 1.25 lb/A on 5- to 7-day intervals. 24-hr reentry.
  9. Microthiol Disperss at 2 to 4 lb/A. May cause injury if applied at higher than 85°F. 24-hr reentry.
  10. MilStop at 2 to 5 lb/A. 1-hr reentry.
  11. Orius 3.6F at 4 to 6 fl oz/A on 10- to 14-day intervals. Do not apply within 7 days of harvest. 12-hr reentry.
  12. Pristine at 12.5 to 18.5 oz/A on 7- to 14-day intervals. Do not tank-mix Pristine with malathion, Kelthane, Thiodan, Phaser, Lannate, Lorsban, M-Pede or Botran as crop injury may result. Do not make more than one (1) application of Pristine or other Group 11 fungicide before alternating to a labeled non-strobilurin fungicide with a different mode of action for at least one (1) application. Pre-harvest interval is 0 days. 12-hr reentry.
  13. Procure 480SC at 4 to 8 fl oz/A on 7- to 14-day intervals. Can be applied up to the day of harvest. 12-hr reentry.
  14. Quadris at 11.0 to 15.5 fl oz/A on 5- to 7-day intervals. Do not apply more than one (1) foliar application of Quadris or other Group 11 fungicide before alternating to a labeled fungicide with a different mode of action. Do not apply within 1 day of harvest. 4-hr reentry.
  15. Quadris Opti at 3.2 pints/A on 7- to 14-day intervals. Do not apply more than one (1) foliar application of Quadris Opti or other Group 11 fungicide before alternating with a fungicide that has a different mode of action. Preharvest interval is 1 day. 12-hr reentry.
  16. Rally 40WSP at 2.5 to 5 oz/A on 7- to 10-day intervals. Application can be made on day of harvest. 24-hr reentry.
  17. Thiolux at 4 to 6 lb/A on 10- to 14-day intervals.
  18. Topsin M 70 WP at 0.25 to 0.5 lb/A on 7- to 14-day intervals. May be applied through sprinkler irrigation lines according to label directions. 12-hr reentry.
Biological control: Efficacy in the Pacific Northwest is unknown.
  1. Serenade WP at 6 to 8 lb/A on 7-day intervals. Can rotate with other fungicides. 4-hr reentry.
  2. Sonata at 2 to 4 qt/A on 7- to 14-day intervals. Can be applied up to and on the day of harvest. 4-hr reentry.
Content edited by: Cynthia M. Ocamb on January 1, 2009
 
Top

In print since 1954 and on the web since 1996. Questions or comments, please contact us.