- Cole crops
- Spinach
- Strawberry
- Keep in mind these disease tracking sites:
- Late blight http://usablight.org/
- Cucurbit downy mildew http://cdm.ipmpipe.org/
Cole crops
Downy Mildew and Alternaria – Symptoms of downy mildew include purple to yellowish-brown spots on upper leaf surfaces. A grayish-white spore mass will develop and cover the underside of leaves under ideal temperatures (night temperatures of 46 to 61°F and day temperatures below 75°F. Downy mildew can kill young plants. Heavily infected leaves may drop providing entry points for bacterial infections (black rot and soft rot).
Symptoms of Alternaria on infected leaves include small, expanding circular lesions with concentric rings that may have a ‘shot-hole’ appearance as lesions age. Heavily infected seedlings may result in damping-off.
Control of Downy mildew and Alternaria begin with preventative fungicide applications. Use one of the following at the first sign of disease and continue every 7 to 10 days (Please refer to the pesticide table on page F27 of the 2013 NJ Commercial Vegetable Production Recommendations to determine which fungicide is labeled for each specific crop.): Quadris (azoxystrobin, 11) at 6.0 to 15.5 fl oz 2.08SC/A, or chlorothalonil (M5) at 1.5 pt 6F/A or OLF, or Cabrio (pyraclostrobin, 11) at 12.0 to 16.0 oz 20EG/A, or Endura (boscalid, 7) at 6.0 to 9.0 oz 70WG/A, or Ridomil Gold Bravo (mefenoxam + chlorothalonil, 4 + M5) at 1.5 lb 76.5WP/A (14-day schedule), or Switch (cyprodinil, 9) at 11.0 to 14.0 oz 62.5WG/A (Alternaria only). For downy mildew only, apply Actigard (acibenzolar-S-methyl, P) at 1.0 oz 50WG/A (begin applications 7-10 days after thinning and re-apply every 7 days for a total of 4 applications per season) or Aliette (fosletyl Al, 33) at 3.0 to 5.0 lb 80WDG/A (on 14-day schedule). For more information please see 2013 New Jersey Commercial Vegetable Production Recommendations Guide.
Spinach
White Rust and Downy Mildew- Prior to symptom development, apply the following on a 7 to 10 day schedule: Quadris (azoxystrobin, 11) at 12.0 to 15.5 fl oz 2.08SC/A, or Cabrio (pyraclostrobin, 11) at 12.0 to 16.0 oz 20EG/A, or Reason (fenimadone, 11) at 5.5 to 8.2 fl oz 500SC/A, or Tanos (famoxodone + cymoxanil, 11 + 27 ) at 8.0 to 10.0 oz 50W/A. Rotate to one of the following fungicides: Ranman (cyazofamid, 21) at 2.75 fl oz 400F/A, Revus (mandipropamid, 40) at 8.0 fl oz 2.08F, or Presidio (fluopicolide, 43) at 3.0 to 4.0 fl oz 4SC/A, or Actigard (acibenzolar-S-methyl, P) at 0.50 to 0.75 oz 50WG/A, or Aliette (fosetyl Al, 33) at 3.0 lb 80WDG/A, or fixed copper (FRAC code M1) at labeled rates (Copper containing fungicides may cause some phytotoxicity), or Ridomil Gold Copper (mefenoxam + copper, 4 + M1) at 2.5 lb 65WP/A (on 14-day schedule). For more information please see the 2013 New Jersey Commercial Vegetable Production Recommendations Guide.
Strawberry
Anthracnose fruit rot – Strawberry anthracnose can be extremely destructive during warm, wet weather causing significant fruit rot. Symptoms of Anthracnose include blackish-brown circular spots on maturing green fruit and soft, sunken (flat) circular lesions on ripe fruit. On ripe fruit, lesions can expand rapidly and are often covered with a pinkish-orange spore mass. Spores are spread from infected to healthy fruit with splashing water. Control of Anthracnose always begins with a 7 to 10 day preventative spray program no later than 10% bloom and/or prior to disease development. For control apply the following combinations:
#1) Pristine (pyraclostrobin + boscalid, 11 + 7) at 18.5 to 23.0 oz 38WG/A
#2) Captan (M3) at 4.0 lb 50WP/A, or Switch ( cyprodinil + fludioxonil,9 +12) at 11.0 to 14.0 oz 62.5 WG/A, or Captevate (captan + fenhexamid, M3 + 17) at 3.5 to 5.25 lb 68WDG/A
#3) Pristine (pyraclostrobin + boscalid, 11 + 7) at 18.5 to 23.0 oz 38WG/A
For subsequent applications, rotate and tank mix between two or more of the following fungicides:
Captan (M3) at 4.0 lb 50WP/A, or Abound (azoxystrobin, 11) at 6.0 to 15.5 fl oz 2.08SC/A, or
Cabrio (pyraclostrobin, 11) at 12.0 to 14.0 oz 20EG/A, or Captevate (captan + fenhexamid, M3 + 17) at 3.5 to 5.25 lb 68WDG/A, or Pristine (pyraclostrobin + boscalid, 11 + 7) at 18.5 to 23.0 oz 38WG/A, or Switch ( cyprodinil + fludioxonil,9 +12) at 11.0 to 14.0 oz 62.5 WG/A
To help manage fungicide resistance development, do not make more than 2 consecutive applications of either: Pristine (pyraclostrobin + boscalid, 11 + 7), Cabrio (pyraclostrobin, 11) or Abound (azoxystrobin, 11) before switching to another fungicide chemistry.
Strawberry
Botrytis (Gray Mold) and Blossom blight – can cause serious losses in strawberry plantings in high tunnels and the field if not controlled properly. Development is favored by moderate temperatures (59 to 77 °F) with prolonged periods of high relative humidity and surface wetness. Control of Gray mold begins with preventative fungicide applications. Apply at 5 to 10 percent bloom and every 10 days until harvest. During periods of excessive moisture, spray intervals of 5 to 7 days may be necessary. Rotate fungicide chemistries to aid fungicide resistance management.
Application #1: Captan (M3) at 4.0 lb 50WP/A plus Topsin-M at 1.0 lb 70WP/A , or Switch (cyprodinil, 9) at 11.0 to 14.0 oz 62.5WG/A
Application #2 : Pristine (pyraclostrobin + boscalid, 11 + 7) at 18.5 to 23.0 oz. 38WG/A, or
Elevate (fenhexamide, 17) at 1.1 to 1.5 lb 50WDG/A
Application #3: same options as application #1.
For subsequent applications, rotate between two or more of the following fungicides:
Captan (M3) at 4.0 lb 50WP/A, or Switch (cyprodinil + fludioxonil, 9 + 12) at 11.0 to 14.0 oz. 62.5WG/A, or Pristine (pyraclostrobin + boscalid, 11 +7) at 18.5 to 23.0 oz 38 WG/A, or Switch (cyprodinil + fludioxonil, 9 + 12), Captevate (captan + fenhexamid, M3 + 17) at 3.5 to 5.25 lb 68WDG/A, or Elevate (fenhexamide, 17) at 1.1 to 1.5 lb 50WDG/A.
