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Hort Update for February 1, 2022

Hort Update for February 1, 2022, Nebraska Extension, https://communityenvironment.unl.edu/update20220201
Warm, dry winter conditions may lead to plant damage this spring.

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Serious ConcernsMajor Symptom
1. Dry, warm winter conditions High potential for turf and woody plant damage by spring
2. February growing degree days (GGD) Lincoln Airport 2/1/22 - 0 GGD,  Understanding Growing Degree Days
Timely Topics
3. Poor water quality effects on turf & landscapes Understanding water test reports
4. Dealing with high fertilizer prices Strategies to reduce fertilizer use
5. Fruit tree spray schedules Spray schedule for homeowners & commercial growers
6. Black knot removal on plums & cherries Hard elongated branch & trunk galls
7. Commercial/Non-commercial pesticide applicator certification New and recertification options
8. Digital Diagnostic Network - Need help with diagnostics? Submit pictures and questions for diagnosis by Nebraska Extension experts.

1. Dry, warm winter conditionsHigh potential for turf and woody plant damage by spring

drought mapWinter conditions continue abnormally warm and dry. Lack of snow or rain is resulting in winter drought conditions for much of the state.  A lack of snow cover or soil freezing allows continuing soil water evaporation, resulting in very dry soils. Unfrozen soil also allows air temperture fluctuations to transfer to the soil, potentially damaging tree and shrub roots. 

Soil freeze in the Omaha area did not occur until approximately December 30, 2021. Currently frost depth in Valley, NE is 9" and frost depth in North Platte, NE is 2". 

Turfgrass
Injury to turfgrass can occur. Desiccation injury is usually greatest on exposed or elevated areas where surface water runoff is great. It is also prevalent on poorly rooted turf that cannot take-up water from deeper in the soil profile. Winter watering is underway on most golf courses where it is feasible and professionals will need to continue monitoring turfgrass sites for dry conditions.

If winter irrigation is used, only water when the soil is not frozen and air temperatures are above 40 degrees F. Lightly irrigate high value turf on dry sunny days when the air temperature is well above freezing where feasible.  The goal is to rehydrate plant crowns (and lower leaves) back to a survivable level and restore soil moisture at the surface.  Avoid excessive quantities of water which may fill soil pores or runoff and present an icing hazard when cold temperatures return.  Also avoid trafficking high value turf areas as winter drought, like summer drought, increases the risk of traffic injury.  To prevent crown hydration injury, avoid watering before a sudden temperature drop is forecast, when the ground is frozen, or in low areas where water might collect and stand due to frozen soil or poor drainage.

Fighting Dessication: Should we water turf in winter?, Nebraska Extension

Trees & Shrubs
Winter dessication injury is often most severe on evergreens and broadleaf evergreens. Damage occurs when the amount of moisture lost through foliage is greater than can be replaced by roots from dry soil. Plant tissue dries out resulting in browning of foliage and dieback, which is often not seen until spring. Injury is found on the outer portion of the branches and is most severe on the side of the tree facing the wind or a source of radiated heat, such as a south or west-facing brick wall or street.

Watering mid-winter is recommended if soils are not frozen and air temperatures are above 40º F. 

When spring arrives, it will be important to remind homeowners not to be in a hurry to prune damaged tissue. While green needles may be brown, the buds on the branches may still be viable and will eventually open. If damage is not too severe and twigs are not killed, the area may eventually fill in. With evergreens, pruning cannot be done past where there is green leaf tissue. If this is necessary, consider replacing the plant with one better adapted to the site.

Green and Growing Tip: Broadleaf Evergreens, Backyard Farmer

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3. Poor water quality effects on turf & landscapesUnderstanding water test reports

When dry conditions occur, there is less leaching of salts from soil during rainfall, along with a higher reliance on irrigation water that could have a high sodium content. This combination of factors increases the risk of problems resulting from poor water quality. It can lead to soil permeability problems, reduced water uptake by plants, plant tissue damage from salts accumulating on foliage and more.  This is one example of the negative effects of poor water quality.

Many turfgrass managers have their water tested, but understanding the values on a water test report can be confusing. The article “What’s in Water?” linked below highlights some important water quality problems, and how to interpret water test reports in order to diagnose and remedy them. It also discusses the importance of understanding how nutrients in irrigation water can impact your fertilization program.

What’s in the Water?, Nebraska Extension Turf iNfo

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4. Dealing with high fertilizer pricesStrategies to reduce fertilizer use

To help offset cost,  base fertilization on soil testing, calibrate equipment correctly, and train crew members so product is not wasted. Below are resources to refer to:

Simplifying Soil Test Interpretations for Turf Professionals, Nebraska Extension Turf iNfo
Calibrating Fertilizer Spreaders for the Home Lawn, University of Kentucky Cooperative Extension

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5. Fruit tree spray schedulesSpray schedule for homeowners & commercial growers

It will soon be time for dormant oil applications on fruit trees. Such applications are typically the start of a fruit tree spray schedule needed to effectively manage insects and diseases. For homeowners who wish to grow fruit that is fairly pest free, the need for a spray schedule is best communicated to them when purchasing fruit trees. A one and be done spray application is rarely sufficient.

Along with marketing disease resistant fruit trees, a good resource to share with homeowners is the Midwest Fruit Pest Management Guide.

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6. Black knot removal on plums & cherriesHard elongated black branch & trunk galls

Black knot is a common problem of stone fruits, especially plum and cherry. The most obvious symptom of this fungal disease are hard, elongated, black galls encircling branches. As knots grow, they eventually cut off flow of water and nutrients to branches, causing stunting, wilting, and dieback.

Pruning is the most important control measure and can reduce infection by 80%. Knots are best pruned out in late winter or early spring before growth begins. It is important to prune at least 2 to 4 inches below each knot because the fungus grows beyond the edge of the knot itself. Sterilize pruning tools between cuts. Bury or burn pruned plant material.

If pruning is not possible because knots are present on major scaffold limbs or the trunk, knots can be removed by cutting away the diseased tissue down to healthy wood and out at least 1/2 inch beyond the edge of the knot. Burn or bury prunings before April 1st.

Fungicides can offer protection against black knot, but are unlikely to be effective if pruning and sanitation are ignored. Fungicides are most needed and provide the greatest benefit if applied before rainy periods when temperatures are greater than 55 degrees F.

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7. Commercial/Non-commercial pesticide applicator certificationNew and recertification options

If you have a pesticide applicators license expiring April 2022 either private or commercial, or you need to get a new license — classes begin soon. Make plans now to attend the training option that fits your needs.

Commercial/noncommercial applicators are professionals who apply restricted-use pesticides for hire or compensation. Anyone who applies pesticides to the property of another person, either restricted- or general-use products, for control of pests in lawns, landscapes, buildings or homes must also have a commercial pesticide applicators license. Public employees (those employed by a town, county, state) applying mosquito control pesticides whether restricted- or general-use, must also hold a commercial or noncommercial certification.

Commercial/noncommercial applicators have four options to recertify or get a new license.

Traditional training classes
Classed begin in late January. Visit https://pested.unl.edu/ for dates, locations and registration. Cost is $80 per online preregistration or $90 per mail or fax registration.

In-person trainings are a supplemental learning opportunity; they DO NOT replace pre-class studying of category manuals or flipcharts for test preparation. Study materials for all commercial categories must be purchased online https://pested.unl.edu/

Conference Options

  • Urban Pest Management Conference - For commercial/noncommercial applicators needing recertification only for General Standards (00), Structural Health (08), Wood Destroying Organismas (08w) and Fumigation (11) categories. Visit https://www.nspca.org/for more information.

Testing-only Options

  • Closed-book exams are given by the Nebraska Department of Agriculture (NDA). Visit the link below for a list of available test-only dates, times and locations, and to register. Cost $5.00, https://pested.unl.edu/.
  • NDA computer-based testing is provided through the Pearson-Vue company. Testing only, no training. Click here for a list of testing sites, categories available, dates, and registration information. Cost $55 per exam. (For applicators with multiple categories on their license, each category is charged the full testing fee.)

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8. Digital Diagnostic NetworkNeed help with diagnostics? Submit pictures and questions for diagnosis by Nebraska Extension experts.

Do you or your clients have questions you need help answering? Maybe you are a lawn care person and they’re asking about trees, shrubs, or flowers? While you can refer them to their local Extension office, another option is Digital Diagnostic Network. Homeowners, lawn care professionals, pest control operators and others are invited to submit questions and photos through this website or with the assistance from an Extension professional at any Nebraska Extension office. All offices are equipped with high-resolution digital image capturing technology. Whether the question is about a lawn weed, insects on a plant, diseases in a shrub border or other, an expert panel of Extension professionals will review and respond to the question. To get started, create an account so the question can be reviewed and responded to via email. For more information and to create an account, go to Digital Diagnostic Network.  

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Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by Nebraska Extension is implied. Use of commercial and trade names does not imply approval or constitute endorsement by Nebraska Extension. Nor does it imply discrimination against other similar products.