Septoria leaf spot (SLS) in Parsley can cause significant losses in fields where it has become established. Like other Septoria’s, the leaf spots produced on parsley look much like the leaf spots produced on tomatoes and other crops. Septoria leaf spot overwinters from year to year on infected debris so long crop rotations of 2 or more years are important to help reduce disease pressure. During the season, SLS will spread rapidly with each subsequent rainfall and/or overhead irrigation event. Therefore, early detection and preventative fungicide applications are key to successfully controlling SLS. There have been a few new fungicides labeled for SLS control in the past few years.
Controlling Septoria Leaf Spot and Bacterial Leaf Blight in Parsley
Septoria leaf spot (SLS) in Parsley can cause significant losses in fields where it has become established. Like other Septoria’s, the leaf spots produced on parsley look much like the leaf spots produced on tomatoes and other crops. Septoria leaf spot overwinters from year to year on infected debris so long crop rotations of 2 or more years are important to help reduce disease pressure. During the season, SLS will spread rapidly with each subsequent rainfall and/or overhead irrigation event. Therefore, early detection and preventative fungicide applications are key to successfully controlling SLS. Unfortunately, very few fungicides are currently labeled making control difficult.
Controlling Septoria Leaf Spot and Bacterial Leaf Blight in Parsley
Septoria leaf spot (SLS) in Parsley can cause significant losses in fields where it has become established. Like other Septoria’s, the leaf spots produced on parsley look much like the leaf spots produced on tomatoes and other crops. Septoria leaf spot overwinters from year to year on infected debris so long crop rotations of 2 or more years are important to help reduce disease pressure. During the season, SLS will spread rapidly with each subsequent rainfall and/or overhead irrigation event. Therefore, early detection and preventative fungicide applications are key to successfully controlling SLS. Unfortunately, very few fungicides are currently labeled making control difficult.
Controlling Septoria Leaf Spot in Parsley
Septoria leaf spot in parsley can cause significant losses in fields where it has become established. Like other Septoria’s, the leaf spots produced on parsley look much like the leaf spots produced on tomatoes and other crops.
Parsley growers who have significant septoria leaf spot issues every year and have seen poor control in fields where FRAC code 11 fungicides have been used considerable in the past should consider no longer using them due to potential resistance issues. Fungicide programs should include Fontelis at a high rate (16.0 to 24.0 fl oz/A) tank mixed with a copper rotated on a weekly basis with Merivon (5.5 fl oz) plus copper. Fontelis has a 3 day PHI and a 72.0 fl. oz season max. Merivon has a 1 day PHI and 33.0 fl. oz season max. Organic farmers should use an OMRI-approved copper fungicide on a regular basis to help suppress septoria leaf spot.
Controlling Septoria Leaf Spot in Parsley
Septoria leaf spot (SLS) in Parsley can cause significant losses in fields where it has become established. Like other Septoria’s, the leaf spots produced on parsley look much like the leaf spots produced on tomatoes and other crops. Septoria leaf spot overwinters from year to year on infected debris so long crop rotations of 2 or more years are important to help reduce disease pressure. During the season, SLS will spread rapidly with each subsequent rainfall and/or overhead irrigation event. Therefore, early detection and preventative fungicide applications are key to successfully controlling SLS. Unfortunately, very few fungicides are currently labeled making control difficult.
Vegetable Disease Update – 9/13/13
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Carrots
Leaf blights – Powdery mildew, Alternaria and Cercospora. Alternaria and Cercospora are two soil-borne fungal pathogens that may cause early defoliation in carrots reducing yields and making harvest difficult. Both pathogens produce distinct symptoms on carrots. Powdery mildew causes characteristic white, powdery lesions on foliage. Symptoms of Alternaria include irregular, dark brown to black spots which typically show up on older leaves first. Cercospora leaf spots are round, grayish-brown and are more prevalent on younger foliage. Both leaf blights typically start at the margins of leaflets and as more spots develop leaflets begin to wither and die. Symptoms similar to leaf infections can develop on stems and petioles.
Control of both diseases begins with regular scouting and preventative fungicide applications on susceptible varieties. Apply Quadris (azoxystrobin, 11) at 9.0 to 15.5 fl. oz 2.08F/A, or Cabrio 20EG (pyraclostrobin, 11) at 8.0 to 12.0 oz/A, or Pristine (pyraclostrobin + boscalid, 11 +7) at 8.0 to 10.5 oz 38WG/A tank-mixed or alternated with chlorothalonil (M5) at 1.5 to 2 pt/A. For Alternaria only: Apply a tank mix of 1.5 to 2.0 pt/A chlorothalonil plus Endura (boscalid, 70 at 4.5 oz 70W/A, or Switch (cyprodinil + fludioxonil, 9 +12) at 11.0 to 14.0 oz 62.5WG/A, or iprodione at 1.0 to 2.0 pt 50WP/A. For more information on tolerant varieties and control please the 2013 New Jersey Commercial Vegetable Production Recommendations. [Read more…]