Cucurbit downy mildew (CDM) has been confirmed on cucumbers in Center Maryland and on the Eastern Shore. It was recently confirmed on cantaloupe in New Castle, Delaware. It was found on butternut squash and cucumber in Lancaster County, PA, on August 18, 2023. CDM has been confirmed on pumpkin, butternut, and spaghetti squash in Northern New Jersey.
Cucurbit downy mildew is a significant disease that affects all cucurbits. Commercially important species of cucurbits include:
Watermelon (Citrullus lanatus).
Muskmelon (Cucumis melo).
Cucumber (Cucumis sativa).
Squash (Cucurbita pepo, Cucurbita moschata).
Pumpkin (Cucurbita maxima).
The causal agent is the fungal-like organism (oomycete) Pseudoperonospora cubensis. CDM falls into two separate clades: Clade I and Clade II. Clade I predominately infects watermelon, pumpkin, and squash, and Clade II predominately infects cucumber and cantaloupe. Research suggests that isolates in Clade II can quickly become resistant to specific fungicides.
For more information on the specific fungicides recommended for CDM control on cucurbit crops, please see the 2022/2023 Mid-Atlantic Commercial Vegetable Production Recommendations. Always read and follow the label, as not all fungicides are listed for all cucurbit crops, and they might have a limited number of applications.
Maryland Department of Agriculture Pivots Toward a More Options-Driven Nutrient Management Plan Writing Program
Annapolis, MD (June 1, 2023) – The Maryland Department of Agriculture today announced a shift in its Nutrient Management Plan Writing Program that will focus on a new approach to education, training, and farmer empowerment. The decision to move to this new options-rich model comes as a greater demand for plan writing has increased following the COVID-19 pandemic.
“The Maryland Department of Agriculture and the University of Maryland have enjoyed a long-standing partnership regarding Nutrient Management Plan writing and that will continue with this new program,” said Maryland Department of Agriculture Secretary Kevin Atticks. “In addition to new incentives for farmers, this program will align with Chesapeake Bay goals while giving Maryland farmers the tools they need to succeed as strong stewards of the environment.”
Maryland law requires all farmers grossing $2,500 a year or more or livestock producers with 8,000 pounds or more of live animal weight to follow nutrient management plans when fertilizing crops and managing animal manure. Nutrient management plans specify how much fertilizer, manure or other nutrient sources may be safely applied to crops to achieve yields and prevent excess nutrients from impacting waterways.
Because of their complexity, these plans must be prepared by a certified University of Maryland specialist, certified private consultant, or farmer who is trained and certified by the department to prepare his or her own plan. Driven by input from industry, the nutrient plan writing program will expand Maryland farmers’ access to nutrient management plan writers and plan writing services, helping farmers meet their environmental stewardship needs and grow compliance with statewide regulations.
The transition is anchored by a valued partnership and educational and training expertise provided by The University of Maryland’s College of Agriculture and Natural Resources, access to new, beneficial cost-share programs and plan-writing services offered by industry professionals.
The new program features a progressive approach that includes the following:
Access to beneficial cost-share programs that will provide partial funding to all eligible farmers in Maryland to access plan-writing services from industry professionals;
Opportunities and workshops to help nutrient management advisors become aware of plan writing employment through the private sector;
Assisting current University of Maryland planners obtain business licenses to write plans privately;
MDA funded UMD specialists providing expanded nutrient management plan writing workshops across the state for ALL Maryland farmers (underserved, small, medium, and large). Support may also be provided to write nutrient management plans for smaller operations;
New opportunities for Maryland-based agricultural organizations to build alliances with privatized nutrient management planning services.
“The time is right to privatize and move in the direction that the department envisioned years ago, and we are supportive of this decision,” said University of Maryland’s College of Agriculture and Natural Resources Dean Craig Beyrouty. “As is our role and duty as a land-grant institution, AGNR is highly motivated to stay involved and help plan writers and producers with nutrient management education, tools, and advice.”
“We would like to recognize the University of Maryland’s College of Agriculture and Natural Resources and its Department of Environmental Science and Technology for their success and contributions over the years,” said Atticks. “We look forward to building upon their strong foundation to take this already successful program to new heights.”
By Jerry Brust, UME and Karen Rane, UMD Plant Diagnostic Lab
One very serious soil disease that affects Allium species, especially onion and garlic, is white rot, caused by the fungus Stromatinia cepivorum (syn. Sclerotium cepivorum (fig. 1)). White rot is NOT the same as white mold, which is caused by Sclerotinia sclerotiorum, which has a very large host range (tomatoes, peppers and 170 other plant species); white rot only infects Allium species.
Fig. 1.) White rot on garlic plant. Photo By K. Rane, UMD,
Leaves of Allium plants with white rot exhibit yellowing, dieback, and wilting. Under ideal weather conditions, white mycelial growth can develop on the bulb. As the disease progresses, the mycelium becomes more compacted with numerous small, spherical black bodies (sclerotia) forming on this white mat (fig. 2). These sclerotia are the overwintering structures of the pathogen and are approximately the size of a pin head. As the disease progresses, these sclerotia are eventually released into the soil. Infected plant roots will rot, making the plant easily pulled from the soil. Disease development is favored by cool, moist soil conditions. The soil temperature range for infection is 50°-75°F, with an optimum of 60°- 65°F. At soil temperatures above 78°F, the disease is greatly inhibited. Soil moisture conditions that are favorable for onion and garlic growth are also best for white rot development.
Fig. 2) Sclerotia (Spherical black bodies a of mycelial growth ) of white rot fungus on garlic. Photo By G. Brust, UMD.
An increase of white rot in a field that has had several Allium crops may go unnoticed for a time as sclerotia numbers increase and disperse. One sclerotium per 20 pounds of soil will cause disease and results in measurable crop loss. The sclerotia will lay dormant until root exudates, exclusively from an Allium species, stimulate germination. Root exudates from non-Allium species will not stimulate the germination of white rot sclerotia. Cool weather is needed for both sclerotia germination and mycelia growth. Mycelia will grow through the soil until they encounter an Allium root at which time the fungus initiates infection. Mycelia can grow from one plant to a nearby plant, allowing the pathogen to move between plants.
Management of white rot should focus on disease avoidance by not introducing the pathogen into a field. Sclerotia can spread throughout a field, or from field to field, through the movement of soil, equipment, or plant material (especially garlic cloves). Sanitation is important to prevent sclerotia from moving from an infested field to a clean field. Plant only clean stock from known origins that has no history of white rot. Always clean soil off of equipment and sanitize with quaternary ammonia before moving to another field. The Allium crops from an infested field should not be used as seed. Rotation alone will not control white rot because sclerotia can survive in the soil for 20-40 years. If the disease is found, reducing or eliminating irrigation will reduce the damage to the current crop but will not stop the spread of the disease.
Because the fungus is vulnerable to temperatures above 115°F, dipping seed garlic in hot water is a possible preventive measure that will reduce the amount of pathogen but will not completely eliminate it. Temperature control is important when using this method because temperatures above 120°F may kill the garlic. There are other cultural and organic practices (i.e., biofumigation and solarization) that a grower might try to fight this disease and these can be found at: https://rvpadmin.cce.cornell.edu/uploads/doc_479.pdf
Chemical applications can be made for white rot management and include for onion tebuconazole applied in a 4-6 inch band over or into the furrow at planting or via chemigation. For garlic an in-furrow at-planting application using iprodione or tebuconazole or fludioxonil can reduce disease incidence, however there are crop rotation restrictions with the use of these chemicals so be sure to check the Mid-Atlantic Commercial Production Recommendations guide for more details.
One other note is that the presence of bulb mites can exacerbate disease problems by opening the bulb up to infection from white rot and growers also will need to manage these mites.
If you grow leeks or onions or other Allium species, you should already be checking for the tell-tale marks left by Allium leaf miner. Allium leaf miner Phytomyza gymnostoma tell-tale marks consist of many linear small white dots (made by the female’s ovipositor) that appear in the middle towards the end of leaf blades (fig. 1) of their preferred hosts of leeks, onions, garlic and other Allium species. Spring crops are usually not as hard hit as fall crops especially when looking at leeks, but this pest has been steadily increasing its geographical range each year as well as its damage potential. If you had some infestation last year you will especially want to be looking for the signs of this pest.
Fig 1.) Onion leaf blade showing linear white dots made by female Allium leaf miners. Photo by Lawrence Barringer, Pennsylvania Department of Agriculture, Bugwood.org
To go over recommendations for this pest: New transplants or seedings of onions, leeks or garlic should be watched closely for the tell-tale signs of the fly’s damage. When eggs hatch the larvae at first mine leaves (fig. 2) and then move down to the bulbs and leaf sheathes where they feed and eventually pupate. Pupae will undergo a summer aestivation (type of hibernation because temperatures are too warm for them to be active) and only emerge again in late September. You can cover any just-transplanted Allium planting with a row cover (but don’t wait too long after transplanting) to keep the flies off or if needed treat with insecticides. Research out of Cornell University has found using just two applications of spinosad (Entrust, which is OMRI-labelled) two weeks after oviposition marks are first found and then another application 2 weeks after this will give adequate control of the pest. But the oviposition marks must be watched for carefully and discovered very soon after first being made. If new oviposition marks are being seen each week a weekly application of insecticide may be necessary. A penetrant adjuvant also is recommended to be used when treating for the larvae.
Fig. 2) Allium leaf miner larva mining in onion. Photo by G. Brust, University of Maryland.
The Department of Agricultural and Resource Economics (AREC) will host five webinars via zoom every Friday starting on Friday, March 31st, and ending on Friday, April 28th. The free webinars will cover those legal issues that Maryland landowners may face. A grant funds the program through the Northeast Risk Management Education Center. The webinars will feature Paul Goeringer, a Senior Faculty Specialist and Extension Specialist in agricultural law. He will address leasing, landowner liability issues, right-to-farm law, fencing laws, livestock liability, and estate planning. As well as additional feature speakers Tim Bishton with Crow Insurance Agency, Stephanie Brophy with Dulany Leahy Curtis & Brophy LLP, and Brooke Schumm with Levin Gann, P.A.
“These webinars will be a great opportunity for landowners and other professionals in rural areas to learn about some of the basic legal issues that many deal with daily. They can understand their rights and responsibilities whether they are involved in agriculture or own land in a rural area,” said Goeringer.
Each webinar will begin at 12:00 pm and run to 1:30 pm. The dates and topics are:
March 31st- Negligence, Livestock, and Guests on Farmland
April 7th- Fencing and Right to Farm
April 14- Agricultural Leasing
April 21- Understanding Insurance
April 28- Working with an Ag Law Attorney
Participants will receive copies of Extension fact sheets and other valuable documents as a part of the workshop series.
For more information, please get in touch with Paul Goeringer at lgoering@umd.edu. This institution is an equal opportunity provider.If you need a reasonable accommodation to participate in any event or activity, please contact Ryan Zimmerman @rzimmer7@umd.edu.
The Maryland Food Safety Network will be hosting a hybrid Produce Safety Rule Grower Training on December 7-8, 2022. The training will be delivered over 2 half-day sessions (December 7, 2022 – 1:00 – 5:30 PM, December 8, 2022 – 12:30 – 4:45 PM). Cost $35. Attend online via Zoom or in person at the UMES Research, Education, & Extension Farm (10789 Stewart Neck Rd. Princess Anne, MD)
The training will cover:
Role of Maryland Dept. of Agriculture and On-Farm Readiness Reviews
Worker Health, Hygiene, and Training
Soil Amendments
Wildlife, Domesticated Animals, and Land Use
Agricultural Water (Part I: Production Water; Part II: Postharvest Water)
MDA’s Small Farm and Urban Agriculture Program is currently offering Small Farm Cover Crop Program grants. Other grant programs are currently under development.
This Program is the first in a series of statewide financial assistance programs to be introduced by the Small Farm and Urban Agriculture Program. It provides needed financial and technical assistance to support small-scale farms located in urban, peri-urban, rural, and suburban areas. Its goal is to increase community access to healthy foods by helping farmers improve their management of natural resources by adopting Bay-friendly and climate-smart farming practices.
Urban and small-scale producers who may not qualify for traditional cover crop programs are encouraged to apply for these small farm cover crop grants. Here are the program highlights:
Urban agricultural growers and small farmers who plant five (5) or fewer acres of a cover crop may apply for our cover crop grants.
Eligible species to be planted include cover crop seed mixes or single cereal grains.
Cover crops may be planted in open plots, raised beds, or a high tunnel following the harvest of a production crop (vegetables, herbs, flowers, sorghum, soybeans, hemp, millet, or tobacco).
Growers should plant fall cover crops following seed company recommendations, but no later than November 30, 2022.
Growers will be reimbursed based on paid receipts with a maximum payment of up to $1,000 per growing season.
Please download an application, instructions, and agreement from the right panel.
FUNDING
This program is funded by the Chesapeake and Atlantic Coastal Bays Trust Fund and managed by the department’s Conservation Grants Program.
Sensor Placement and Floating Row Cover Impact on Fruit Rotting Diseases in Strawberries
Scott D. Cosseboom and Mengjun Hu Department of Plant Science and Landscape Architecture, University of Maryland College Park
Various sensors can be used to monitor environmental variables in fields, including ambient temperature, relative humidity, rain depth, wind speed, leaf wetness (LWD), soil temperature, and soil moisture. These can be critical variables for decision making for crop protection or yield prediction. These data (namely ambient temperature and LWD) can also be useful for disease prediction models such as those used for Botrytis (BFR) and anthracnose (AFR) fruit rots of strawberry (Hu et al. 2021). A traditionally placed weather station at the edge of a field (see ‘elevated’ station below) may also not fully capture the conditions in the field. Floating row covers are a common tool in Mid-Atlantic strawberry fields for manipulating the crop microclimate for facilitating crop development under cold conditions and for protecting from freeze events. Therefore, covered strawberry plants should have a vastly different microclimate than would be reported from traditionally placed weather stations or non-covered plants. We evaluated differences in sensor readings based on placements either in the canopy or in the traditional, elevated setting. We also evaluated the effect of row covers on the sensor readings. Lastly, we evaluated how these different placements would affect disease prediction models utilized in a fungicide spray program.
If you had plants in high tunnel this season that were showing drought and salt stress in the form of poor growth, thin canopy, excessive leaf drop, poor fruit set, poor yields, necrotic leaf margins, especially on older leaves that can curl, then you might want to consider testing your soil for high soluble salts. These excess soluble salts often come from compost, manure, or fertilizers frequently applied without sufficient water (rain) to leach them through the soil.
High soluble salt levels in the soil can harm crops via drought stress in several ways. First, they can draw water away from plant roots resulting in wilted foliage and damaged roots (fig. 1). The plant roots can also absorb the excess soluble salts in the soil but cannot metabolize them. The soluble salts enter the roots and are moved through the water-conducting tubes to the leaves, where the water evapotranspires, gradually concentrating the salts to toxic levels.
Figure 1.) Lettuce seedling showing burned rootlets. Photo: Gerald Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org
Some vegetable crops are much more sensitive to soluble salts than others. Crops such as green beans, onions, and peas are the most sensitive, while cabbage, cucumbers, peppers, and potatoes are a bit salt tolerant. Broccoli, squash, and tomato are moderately salt tolerant.
Some possible remedies for high salts include having adequate drainage to help move salts out of the root zone and flushing the soil with as much water as possible for several days. When doing this, slowly apply the water, so it seeps into the soil and does not runoff. After the season, it may be best to take the plastic off the high tunnel and allow rain and snow to move the salts out of the growing zone, but you need to know if you have high soluble salt levels first, so it’s best to that soil test.
RMA Offers Virtual Workshops on Improvements to the Whole-Farm Revenue Protection and Micro Farm Insurance Options
The U.S. Department of Agriculture (USDA) is offering virtual workshops on Nov. 15 and Dec. 13 for agricultural producers and stakeholders to learn about the latest updates and improvements to the Whole-Farm Revenue Protection (WFRP) and the Micro Farm insurance options. WFRP and Micro Farm are two of the most comprehensive risk management options available. USDA’s Risk Management Agency (RMA) will announce in-person events later this fall. These insurance options are especially important to specialty crop, organic, urban and direct market producers. Policy improvements and these workshops are part of RMA’s efforts to increase participation in crop insurance.
“We want to make sure farmers and ranchers know about these very important insurance options. We invite specialty crop, organic, urban and direct market producers to join the virtual ‘RMA Roadshow,” RMA Administrator Marcia Bunger said. “The RMA Roadshow will include me and leadership to highlight important improvements to Whole-Farm and Micro Farm and answer your questions.”
Improvements include:
Doubling the maximum insurable revenue under WFRP, now up to $17 million
More than tripling the size of farm operations eligible for Micro Farm to $350,000 in approved revenue
