- Downy mildew was confirmed on pea last week. The cool, damp weather the past week has been ideal for downy mildew development on spring crops.
- Soft rot, caused by Pectobacterium spp., was detected on planted potato seed last week in southern New Jersey.
- Bacterial leaf spot in romaine lettuce was found in the past week.
- The heavy rains and damp, cool weather have been ideal conditions for early-season damping off caused by Pythium and Phytophthora as well as downy mildew development on spring greens. Growers should continue to scout on a regular basis and remain proactive in their fungicide programs as long as current weather patterns continue.
- Cucurbit downy mildew has been reported on cucumber as far north as central North Carolina this week.
- No Late blight has been reported in region to date.
May 30, 2018 Andy Wyenandt
Vegetable Disease Update – 5/30/18
April 24, 2018 Andy Wyenandt
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.
Septoria leaf spot of Parsley
April 24, 2018 Andy Wyenandt
Damping-off: Identifying and Controlling Early-Season Pathogens
It is extremely important to know which pathogen is causing damping-off problems and which fungicide to properly apply. The key to controlling damping-off is being proactive instead of reactive. Always refer to the fungicide label for crop use, pathogens controlled, and application rates.
Damping-off is caused by a number of important vegetable pathogens and is very common during the spring. Damping-off can kill seedlings before they break the soil line (pre-emergent damping-off) or kill seedlings soon after they emerge (post-emergent damping-off). Common pathogens that cause damping-off include Pythium, Phytophthora, Rhizoctonia and Fusarium spp.
Control of damping-off depends on a number of factors. First, is recognizing the conditions which may be leading to the problem (i.e., weather/greenhouse growing conditions) and second, identifying the pathogen causing the problem.
Conditions Favoring Damping-off
Although all four pathogens are associated with damping-off, the conditions which favor their development are very different. In general, Phytophthora and Pythium are more likely to cause damping-off in cool, wet or overwatered soils that aren’t allowed to dry out due to cloudy weather or cooler temperatures. Conversely, Rhizoctonia and Fusarium are more likely to cause damping-off under warmer, drier conditions especially if plug trays are kept on the dry side to help reduce transplant growth. [Read more…]
April 24, 2018 Andy Wyenandt
Controlling Spring Diseases in Asparagus
Asparagus season is just around the corner and now is a good time to review important diseases.
Wet soil conditions are ideal for Phytophthora and Pythium development. To help reduce potential losses, especially in fields with low spots or fields that are poorly drained soils, or more importantly, in fields with a history of either disease apply Ridomil Gold 4SL (mefenoxam, 4) at 1.0 pt/A, or Ultra Flourish 2E/A (mefenoxam, 4) at 2.0 pt/A, or MetaStar 2E (metalaxyl, 4) at 2.0 qt/A over beds just before first harvest. For new plantings, apply the same after planting or after crown covering. Do not apply Ridomil or MetaStar one day prior to harvest or illegal residues may result. [Read more…]
April 24, 2018 Andy Wyenandt
Controlling Strawberry Fruit Rots – 2018
Anthracnose Fruit Rot of Strawberry
Fruit rots in strawberry can cause significant losses if not recognized early and controlled. The use of good cultural practices such as keeping fields weed-free and promoting good drainage, long crop rotations, and preventative fungicide applications are critical.
Pathogens such as anthracnose, gray mold (Botrytis), and leather rot (Phytophthora) can become systemic problems in strawberry plantings once established. All three fungal diseases are soil-borne and once in fields can be difficult to manage over the lifetime of the planting.
The use of mulch (matted rows) to prevent/reduce soil splashing and keeping fruit from coming into direct contact with the soil surface can be beneficial in organic production systems where conventional fungicides cannot be used. Use of long crop rotations and staying away from areas of the farm with known instances of any of these pathogens is also important. Remember that same species of Colletotrichum that causes fruit rot in pepper and other crops can also infect strawberry.
February 20, 2018 Andy Wyenandt
Fungicide resistance management guidelines for cucurbit powdery and downy mildew control in 2018
Extension specialists in the mid-Atlantic and Northeast regions have put together new guidelines for cucurbit powdery and downy mildew control. These new guidelines list all recommended fungicides and their efficacy ratings for controlling both diseases based on recent fungicide efficacy trials. Also included in the new FRAC table are notes on fungicides where resistance has been detected in the region. The new FRAC table can be downloaded for FREE on American Phytopathology Society’s Plant Health Progress website.
