Andy Wyenandt

This is an archive of Dr. Wyenandt's posts on the Plant and Pest Advisory.

Anthracnose and Botrytis Control in Strawberries for 2022

Dr. Mengjun Hu, University of Maryland, and Kathy Demchak, Penn State University, have written an extensive article on effective strategies for Botrytis and Anthracnose fruit rot control for the 2022 season.

Managing gray mold (Botrytis) on strawberries is increasingly challenging because of fungicide resistance development, plus a new Botrytis species that is less susceptible to fungicides is becoming common in the mid-Atlantic region. Resistance to certain fungicides is also a problem in management of anthracnose fruit rot. This article describes disease management strategies designed to slow further resistance development, while also providing specifics for managing our two most common fruit rots.

The rest of the article can be accessed and downloaded as a PDF file by clicking on the following link: Botrytis and Anthracnose Mgt Strawberries final.

Understanding Protectant Fungicides
(FRAC groups M01 – M12) in 2022

Protectant (contact) fungicides, such as the inorganics (copper, FRAC group M01) and sulfur (FRAC code M02); the dithiocarbamates (mancozeb, M03), phthalimides (Captan, M04), and chloronitriles (chlorothalonil, M05) are fungicides which have a low chance for fungicide resistance to develop. Protectant fungicides typically offer broad spectrum control for many different pathogens.

Why wouldn’t fungi develop resistance to protectant fungicides? Protectant fungicides are used all the time, often in a weekly manner throughout much of the growing season.

[Read more…]

Damping-off: Identifying and Controlling Pathogens in Transplant Production in 2022

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 transplant production. 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.

[Read more…]

2021 Phytophthora and Bacterial leaf spot bell pepper variety trial reports

Phytophthora blight caused by Phytophthora capsici is one of the most economically important diseases in pepper, tomato, and cucurbit production in New Jersey. The pathogen was first identified in a pepper field in southern New Jersey in 1971. Each year for the past three decades Rutgers has evaluated new bell pepper cultivars and breeding lines for their resistance to P. capsici in field trials at the Rutgers Agricultural Research and Extension Center (RAREC) near Bridgeton, New Jersey, and in some years, at research trials on farms near Vineland, NJ. The pathogen, an oomycete – ‘water mold’ is favored by warm weather and wet soils during the production season and can survive between seasons in the soil as oospores. Once found in a field, the pathogen can establish itself, and be very difficult to control even with the use of fungicides because of resistance development. Fortunately, in bell pepper, highly resistant or intermediate resistant cultivars to Phytophthora blight have been commercially-available for over 20 years now and have been used extensively by bell pepper growers throughout the state. Each year, Rutgers also evaluates each cultivar for their fruit quality characteristics (e.g., color, wall thickness, number of lobes, and development of ‘silvering’) to make sure they meet the needs of growers. Unfortunately, phytophthora resistant cultivars such as ‘Paladin’ which have been used extensively in southern New Jersey for the past 20 years appears to be breaking down. Because of increasing reports of bacterial leaf spot and copper resistance in recent years, bell peppers grown in NJ at some point will need to consider growing those cultivars with X10R resistance and phytophthora blight resistance. Importantly, for organic bell pepper growers, if you have not already done so, you should be evaluating these new lines to see if they meet your needs. The easiest way to mitigate both diseases are to start with genetic resistance. Below are the bell pepper variety and bacterial leaf spot reports for 2021.

Pepper Phytophthora Blight Final Report

Bacterial Leaf Spot Final Report

For more information on recommended bell pepper cultivars please visit the Pepper Section in the 2022/2023 Mid-Atlantic Commercial Vegetable Productions Recommendations Guide.

 

By: Andy Wyenandt and Wesley Kline

 

2022/2023 Mid-Atlantic Commercial Vegetable Production Recommendations Guide available on-line now!

The 2022-2023 Mid-Atlantic Commercial Vegetable Production Recommendations is FREE to download online. The new recommendations guide has been updated by 44 Extension professionals from the six states (NJ, PA, DE, MD, VA, and WV) in the mid-Atlantic region and includes up to date information on all aspects of vegetable production such as variety recommendations, pest management, and specific crop recommendations. The guide also includes a new Edamame section, expanded new tables for fungicide and insecticide use in the greenhouse, and up to date pesticide safety information.  The complete guide (464 pages) or specific sections can be downloaded by clicking the link above.

Nematodes in Atlantic Soybean Production Webinar

Nematodes consistently rank as a top yield robber of soybeans. Join us November 16 from 9:00 AM-12:00 for the Nematode in Atlantic Soybean Production Webinar to discuss nematode distribution and management strategies for the region. The webinar is free, but registration is needed for access to the zoom link. Registration information can be found at https://www.pcsreg.com/nematodes-in-atlantic-soybean-production-webinar.  Topics of emphasis will include updates from regional nematode distribution surveys, assessment of soybean cyst nematode seed treatments, root knot nematode on-farm field trials, general management strategies, and how to collect and submit soil samples. Please email Alyssa Koehler akoehler@udel.edu with any questions.