Upcoming UME Events

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Upcoming UME Events

Additional upcoming events can be found on the UME events website. This institution is an equal opportunity provider. If you need a reasonable accommodation to participate in any event or activity, please contact your local University of Maryland Extension Office 2 weeks prior to the event.

The Maryland State Horticultural Society Summer Tour

Visits the Eastern Shore
When: July 10, 2024. Bus pick up in Frederick – 7:00am, Pick up in Gambrills – 9:00 am.
Where: Emily’s Produce, Seaberry Farm, and Blades Orchard. Lunch is included
Registration: https://www.eventbrite.com/e/maryland-state-horticultural-society-summer-tour-2024-eastern-shore-tickets-929371153137?aff=oddtdtcreator
For more information, Contact Chuck Schuster 410-596-2159

Good Agricultural Practices, Introduction to Produce Safety Rule, In Person
When: July 15, 2024, 8:00am – 4:30pm & July 29, 2024, 8:00am – 4:30pm
Where: Central Maryland Education and Research Center, 4240 Folly Quarter Rd., Ellicott City, MD 21042
Cost: Free
Registration: https://www.eventbrite.com/e/good-agricultural-practices-introduction-to-produce-safety-rule-in-person-tickets-937986652327?aff=oddtdtcreator
For more information: Carol Allen, callen12@umd.edu

Urban Farm Twilight Tour & Ice Cream Social
When: July 17, 2024, 5:00 – 7:30 pm
Where: Anne Arundel Extension Office, 97 Dairy Lane, Gambrills, MD.
Cost:Free
Registration: https:/go.umd.edu/2024UrbanfarmIcecreamsocial

Lower Shore Vegetable Twilight Tour.
When: Aug 6, 2024, 5:00-8:30 pm.
Where: Lower Eastern Shore Research & Education Center, 27664 Nanticoke Road, Salisbury, MD
Cost: Free
Registration: https://go.umd.edu/2024lesrecVEGtwilight
For more information: Emily Zobel 410-228-8800

Summer Vegetables Twilight Tour – Featuring Watermelons, Sweet Corn and Tomatoes
When: August 20, 5:30-7:30 pm
Where: Wye Research and Education Center, 211 Farm Lane Queenstown, MD 21658
Cost: Free
Registration:  https://docs.google.com/forms/d/e/1FAIpQLScFgRMmsEKosDQ-Bc67yR9WCjCRKTxtEaTF738en_m2OGW1ZA/viewform?usp=sf_link
For more information: Megan Messix Stibbe at (443) 446-4248 and mstibbe@umd.edu or Chris Cochran at (443) 988-8595 or ccochra3@umd.edu.

Heat Stress on Plants

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While part of Maryland got some rain this week, the past two weeks have been hot and dry so that you might see symptoms of heat stress on plants. 

Heat stress occurs when plants are exposed to enormous amounts of sunlight and heat for an extended period of time. The ideal range for most crops is between 68 and 86 degrees Fahrenheit (20 and 30°C). Temperatures outside this range, whether in the air or the soil, during the day or the night, are harmful to plants. The term “heat stress” often refers to a period in which plants are subjected to high temperatures long enough to alter their ability to function or grow normally.  

Heat stress disrupts various plant processes, such as inhibiting the growth and development of plant tissue, reducing the photosynthesis rate and nutrient uptake, reducing pollen production, causing flower and fruit drop, and causing sunscald on fruit.  Shallowly rooted and young plants will be the most impacted by heat and drought. 

Common visual signs of heat injury in plants include the following: leaf rolling and cupping, leaf drop, scalding and scorching of leaves and stems, rapid leaf death, reduction in growth, and lower yields. Wilting is the primary sign of water loss, which can lead to heat damage.

Drought and heat stress on green bean plants.
Photo by Howard F. Schwartz, Colorado State University, Bugwood.org

High temperatures can also cause increased sunburn and other developmental disorders in fruits and vegetables. High nighttime temperatures decrease pollen production, reducing fruit sets and smaller fruit. Flower abortion can happen at temperatures ranging from 75° F to 95° F, depending on the crop.

Some vining vegetables in the cucurbit family (pumpkins, squash, melons, cucumbers, and the like) will develop more male flowers than female flowers in high temperatures (over 90° F during the day and 70° F at night).

REDUCING PLANT HEAT STRESS

  • A great way to reduce heat stress on plants is by meeting their water need. Plants keep cool through the evaporation of water from their leaves. If a plant lacks water, it will close the pores in its leaves (stomates), preventing evaporation to avoid wilting. When stomates close, the plant can no longer keep itself cool and leaves heat up, causing stress. Morning watering is often prescribed in times of high heat.

  • Using overhead watering, sprinkling, and misting can provide humidity, which we typically avoid to decrease plant disease; however, in prolonged high temperatures, the benefit of a humid environment probably outweighs the risk of plant disease.
  • By adding compost to your soil, you can increase its organic matter and, in turn, its water-holding capacity.

  • Mulches can also help reduce heat stress by increasing the reflection and dissipation of radiative heat. Reflective mulches like straw and wood chips can reduce surface radiation and conserve moisture.   Black plastic mulch is excellent for heating the soil in the spring to allow for early plant growth. However, its surface temperature can exceed 130°F on a hot sunny day, resulting in injury or desiccation of most plant parts (root, stem, leaves, and fruits) in direct contact with the mulch.  White or metalized plastic can be used for summer crops that are more at risk of heat damage. However, these plastic mules tend to be more costly.  An alternative to white and metallic mulches could be to make a foliar application of kaolin clay. The white coating of kaolin clay would serve as a reflective layer on the black mulch and plant canopy to minimize temperature changes.  A study conducted at the Eastern Shore Agricultural Research and Extension Center in Painter, Virginia, found that 20 to 40 lb/A of kaolin clay could maintain 10⁰F cooler soil temperatures compared to black plastic.

  • Shade cloth has been shown to significantly benefit heat-sensitive crops if applied correctly by reducing the soil and air temperatures around them. Shade cloth can be placed over crops, using stakes or hoops as support; it can be particularly beneficial to sun-sensitive crops such as peppers and tomatoes. Research at UDel by Dr. Emmalea Ernest found that a 30% shade cloth provides adequate cooling without blocking too much light for most vegetables.

  • Avoid applying fertilizers and pesticides when temperatures are consistently above 80°F, as they can burn crops. Check the product’s label for specifics before applying. 

2024-2025 Mid-Atlantic Commercial Vegetable Production Recommendations Guide

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The 2024-2025 Mid-Atlantic Commercial Vegetable Production Recommendations Guide books are in.

 You can find a free pdf on the UME Vegetable webpage . 

Paper copys of the guide are available for $25 (plus shipping). Please reach out to your local extension office if you are intrested in purchasing one.

These recommendations are intended for the commercial vegetable grower who has to make numerous managerial decisions. Although the proper choices of variety, pesticides, equipment, irrigation, fertilizer, and cultural practices are the individual vegetable grower’s responsibility, it is intended that these recommendations will facilitate decision-making. Recommended planting dates will vary across the six-state region. Local weather conditions, grower experience, and variety may facilitate successful harvest on crops planted outside the planting dates listed in this guide.

 

Inside the guide you will find information about general production recommendations, soil and nutrient management, irrigation management, pesticide safety, pest management and specific commodity recommendations

 

 

 

Monthly Insect & Disease Scouting Tips – Sept 2023

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September Insect & Disease Scouting Tips

By Emily Zobel, AgFS Agent, Dorchester County, UME
ezobel@umd.edu

 Cole Crops/ Brassicas: Continue to scout all fields for caterpillar pests (armyworm, diamondback moth larvae (DBM), and cabbage looper larvae). For fresh-market crops, treat when 20% of the plants are infested during the seedling stage, then 30% infestation till the cupping stage. Use a 5% threshold from early head to harvest for cabbage and Brussels sprouts. For broccoli and cauliflower, use 15% at curd initiation/cupping, then 5% from curd development to harvest.

Good identification as early as possible is important because some products may not be labeled or as effective for all brassicas caterpillar pests. If treatment is needed, adjust your spray pattern so that the spray is getting sideways to the undersides of leaves, particularly when using Bt and other contact materials. Due to resistance development, pyrethroid insecticides (Group 3A) are not recommended for controling DBM. Effective materials should eliminate DBM larvae within 48 hours. Make sure to re-scout treated fields within 3 days to assess the efficacy of the insecticide applications.

Check young plants for flea beetles. Thresholds for flea beetles are 1 per transplant or 5 beetles per 10 plants. They will lay eggs in the soil, and larvae can cause significant root injury. Downy mildew and Alternaria can be problematic in fall brassica crops (cabbage, collards, broccoli, cauliflower, and kale). When the disease first appears, apply a fungicide every 7 to 10 days.

Alium crops: Scout fall leeks, garlic, or other Allium species from now until the first freeze for Allium leaf miner damage. Egg-laying damage consists of several small round white dots (made by the female’s ovipositor) that appear on the leaf blades (fig 1). Larvae will live inside the leaves before moving down to the bulbs, where they feed and eventually pupate and overwinter. The feeding damage can open up the foliage and bulb to fungal infections. Row covers can be used to exclude this pest when Alliums are first planted. For organic production, spinosad (Entrust is OMRI-labelled) works well in controlling the larvae. Two or three applications of the insecticide used 2 weeks apart from each other, with the first one coming only after oviposition marks are seen, should offer good control of this pest. The use of a penetrant adjuvant such as neem oil is recommended for better control. 

Image of a Onion leaf blade showing linear white dots made by female Allium leaf miners.
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

Lima Bean: Check any latelima bean for soybean looper and stink bugs. Looper activity should decline once nighttime temperatures drop into the low 50s.

Swiss chard, Beets & Spinach: Check for beet webworm. They fold leaves and cause window-paning feeding damage. They also feed on pigweed.

Sweet Corn: Corn earworm (CEW) numbers have been declining across the state. Cooler night temperatures and shorter day lengths have triggered mature larvae to enter diapause as overwintering pupae.

Spider mites: Now is a great time to treat weeds growing in and around greenhouses. Winter annual weeds such as chickweed, henbit, dead nettle, and speedwell serve as spider mites and thrip habitats, allowing them to overwinter. Treating now will reduce the possibility of having early-season pest activity on transplants next year.

 

Superficial Scald in Apples: Strategies and Solutions

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By Agustina Salas (Candidate for B.S. in Biology Pontificia Universidad Católica de Chile) & Macarena Farcuh, Ph.D., UMD

What is superficial scald in apple fruits and what causes it?

Physiological disorders correspond to abnormalities that can occur in any of the apple tissues, and can result in loss of quality, marketability, and profitability, leading to increased loss and wastage of apples. These disorders are caused by abiotic factors such as genotype/genetic background, maturity at harvest, orchard/preharvest factors, seasonal variations, and postharvest storage conditions. It is important to mention that pathogens or mechanical damage do not lead to physiological disorders.

In particular, the physiological disorder of superficial scald in apples is the result of a chilling injury. Chilling injuries occur during cold storage at temperatures below the optimum range. During apple cold storage fruits can accumulate a-farnesene, a volatile compound present in the fruits’ wax layer. This compound can cause superficial scald when it oxidizes with atmospheric oxygen. Therefore, superficial scald generally develops during cold storage (more than 3 months in storage) but it is increased 3-7 days after taking the fruit out of cold storage.

Granny Smith apples with superficial scald on their skin.
Fig 1. Apples (Granny Smith) affected with superficial scald on their skin. Photo: Fresh Quarterly issue 9 June 2020.

Superficial scald is only restricted to the skin of the apples and usually on the shaded side. The symptoms appear as brown patches on the skin of the apple, which are diffuse (no defined edges between affected and unaffected skin) irregular, and light brown to dark brown to black in color. Superficial scald can also be accompanied by the development of a rough texture of the fruit.

Continue reading Superficial Scald in Apples: Strategies and Solutions

Cucurbit Downy Mildew Alert! 

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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.

Most fungicides labeled for the control of CDM are at risk for resistance development because of the specific modes of action. Growers should scout their cucurbit fields every week, note the efficacy, or lack thereof, seen in the field, and incorporate using as many different chemical groups as possible to help mitigate fungicide resistance development. Loss of efficacy in the control of CDM has also been documented in FRAC code 4 (mefenoxam), FRAC code 11 fungicides (azoxystrobin), FRAC code 28 (propamocarb HCL), and FRAC code 43 (fluopicolide) in the mid-Atlantic region.

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

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 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.”

For a list of frequently asked questions related to the future of this program please visit the Maryland Department of Agriculture’s website at mda.maryland.gov.

United States Department of Agriculture (USDA) Changes to Audit Costs

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USDA has just announced that proposed audit fees for the Harmonized and GAP/GHP audits will increase to $155 per hour. The average Harmonized Audit runs anywhere from 12 to 15 hours, GAP/GHP audits average 5 to 10 hours. The current fee is $132 per hour. For anyone who needs an audit try to schedule before October 1, 2023 when the new rates take effect.  For further information or discuss the proposed increases contact:  Melissa Bailey, Associate Administrator, AMS, USDA, Room 2036–S, 1400 Independence Ave. SW, Washington, DC 20250; telephone (202) 205–9356, or email melissa.bailey@usda.gov.

Spinach Crown Mites in Spinach

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Spinach Crown Mites in Spinach
by Jerry Brust, UME

Spinach crown mites Rhizoglyphus sp. feed within the folds of new leaves in the crown of spinach plants. This feeding causes the new leaves to become deformed as they grow (figs.1 and 2). Crown mite adults are extremely small bulbous nearly transparent mites that also may have a yellow-beige body color with reddish-brown legs (fig 3). A good characteristic to look for to identify these mites is the sparse long hairs mostly found on the back end of the mite (fig. 3). Crown mite eggs are spherical and clear and laid on the creased leaf surfaces in the crown area. Some reports state that crown mites can act as vectors for plant pathogens such as Pythium and Rhizoctonia, but this is not definitive.

Feeding by spinach crown mites can cause misshapen and ragged leaves with necrotic margins as they expand and crown leaves are distorted and wrinkled in appearance.
Figs. 1 & 2.) Crown leaves fed on by spinach crown mites are misshapen and ragged with necrotic margins as they expand and in the field the crown leaves are distorted and wrinkled in appearance. Photos by G. Brust, UMD.

The spinach crown mite is most damaging in soils high in organic matter and under cool moist conditions (weather conditions we have had this past week). Because these mites can consume organic matter they can survive in soils after the crop has been removed. This is one reason they are difficult to control as they can survive for fairly long periods of time with no crop being present. The other reason they are difficult to ‘control’ is we do not realize they are causing the problem until it is too late.

Spinach crown mite adult with sparse long hairs over its body.
Fig 3.) Spinach crown mite adult with sparse long hairs over its body. Photo by G. Brust, UMD.

Most control recommendations include sanitation and crop rotations as being important as are fallow periods. Pyrethroids are a possible chemical control as is Neem; any chemical control has to get down into the crown of the plant to have any chance of working. There has been little research conducted on the most efficacious material for these mites. Mostly what is needed are warm sunny days where spinach can grow well and the environment is not so conducive to the mites.

Russet on Apples: Current Understanding and Management

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Russet on Apples: Current Understanding and Management

By John Skae, Candidate for B.S. in Physiology and Neurobiology, and  Macarena Farcuh, Ph.D. Assistant Professor and Extension Specialist,  UMD

What is russet on apples?

Russet on apples is a disorder of the skin that results in discoloration and changes to the expected smooth texture of the skin of apples. Russet appears as a spectrum from mild brown weblike patterns to severe rough changes on the surface of apples and many variations in between (Fig. 1). Russeting is only skin deep and thus will not affect the flesh of the fruit. It can occur due to naturally-occurring weather conditions, particularly humid and wet weather.

Fuji apple expressing russeting.
Fig 1.) Fuji apple expressing russeting. Source: John Skae, University of Marylan

Russeting can ultimately reduce the market value of apples, decreasing grower profitability. According to the US Department of Agriculture, the presence of russet disqualifies apples from the US Extra Fancy, US Fancy grades if smooth, solid russeting is more than 10%, while excessive russeting or smooth net-like russeting exceeding 25% excludes fruit from the US No. 1 grade categories.

Apples can begin to russet within the first 30-40 days of development, starting at petal fall. The earlier the tissues are damaged, the more dramatic the damage will be. But it is important to mention that russet can also be developed later during the growing season. Russeting occurs because cracks begin to develop underneath the cuticle of the apple. The damage in the epidermal cells underneath the cuticle turns brown. The cells are then pushed upwards towards the skin because new cork cells are growing underneath the affected epidermal cells. Once the damaged cells reach the surface of the apple, they form phellogen, a wound-sealing tissue created as a result of the russeting reaching the surface. Although russeting affects the cosmetic appearance of apples, it does not harm fruit flesh taste.

What factors cause or contribute to apple russeting?

Some cultivars produced by selective breeding are more prone to russeting than others as these can alter the genetic makeup of the apple to express russet. For example, Golden Delicious apples are highly susceptible to russet, while Red Delicious apples rarely express the russeting disorder.

Continue reading Russet on Apples: Current Understanding and Management