Like clockwork, purple spot has appeared in some asparagus plantings during mid- to late-April for the past 3 years. Purple spot, caused the soil-borne fungus, Stemphylium vesicarium, can cause problems during cool, wet spring weather (much like we have had over the past week or so). Symptoms, just like its name, include numerous, sunken oval-shaped spots on spears during the harvest season and more importantly on ferns and stalks during the summer months as long as conditions are ideal for its development. Often, purple spot will disappear as quickly as in appears on spears during the spring production season depending on the local weather conditions. As soon as the weather becomes dry and warm (as it appears for the weekend), expect purple spot to disappear. [Read more…]
Controlling Strawberry Fruit Rots – 2017
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.
UMaine to Hold International Potato Disease Summit Nov. 9, 2017
Orono, Maine — Two bacteria threatening the potato industry worldwide will be the focus of a Potato Disease Summit Nov. 9 in Bangor, Maine, convened by the University of Maine.
Plant pathologists, researchers and scientists from The Netherlands, Scotland and five U.S. states will present the latest information on the bacteria — Dickeya and Pectobacterium — that cause blackleg disease, an emerging potato seed problem.
In the past three growing seasons, Dickeya, a bacterial pathogen of potatoes, has caused significant economic losses in seed nonemergence and crop loss nationwide. In addition, an associated pathogen, Pectobacterium, has caused potato crop losses in the field and in storage. The bacteria have caused losses to the potato industry in Europe for an even longer period.
“The University of Maine is responding to this situation by holding an international summit focused on the latest research and what steps are needed to help the potato industry,” says University of Maine President Susan J. Hunter. “As Maine’s only public research university, we are a longstanding partner with the state’s potato industry in addressing its needs, including the growing threat posed by Dickeya and Pectobacterium.”
The Potato Disease Summit, 8 a.m.–5 p.m., Nov. 9 at the Cross Insurance Center, 515 Main St., Bangor, Maine, is designed for scientists, consultants, regulatory officials, and potato seed growers and buyers. It will focus on such topics as current advances in detection and diagnosis of Dickeya; an overview of Pectobacterium in the U.S.; and management of Enterobacteriaceae spread and risk.
The $80 per person fee includes materials, lunch and breaks. Registration deadline is Oct. 2 and is available online: extension.umaine.edu/agriculture/programs/dickeya-and-pectobacterium-summit.
For more information or to request a disability accommodation, contact Steve Johnson, 207.554.4373, stevenj@maine.edu.
Vegetable Disease Update – 4/17/17
Vegetable Disease Notes:
- Powdery mildew has been reported in a number of tomato greenhouse operations. For control of powdery mildew and other important diseases in greenhouses and high tunnels please see Table E14 on pages E52-E54 of 2016-2017 Commercial Vegetable Production Recommendations Guide.
- A new article on the importance of testing for Dickeya dianthicola in potato seed can be found here.
[Read more…]
Vegetable Disease Update – 4/10/17
Asparagus
Phytophthora crown and spear rot – In fields with low spots (poorly drained soils) or fields with a history of crown and/or spear rot 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 1st 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. For more information please see the 2016-2017 Mid-Atlantic Commercial Vegetable Production Recommendations Guide. [Read more…]
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…]
