Green Industry Resources
Hort Update- Seasonal Information for the Green Industry
Hort Update for the week of 4/1/2010
Bold items are new in this issue of Hort Update
|1. Gray snow mold||Circular patches of tan turf under snow cover|
|2. Ice damage/oxygen deprivation|
Dead or slow to green up areas of turf
|3. Wet soils||Dryer conditions are needed before cultivation or increasing traffic on lawns|
|4. Wait for soil warming to seed||Sustained temperatures of 50°F needed|
|5. Earthworms||Increased activity observed; no pesticides labeled for control|
|6. Home soil test kits||Soil labs more precise; home kits provide general information|
|7. Voles||Surface runway damage apparent after snow melt|
|Trees, Shrubs & Fruit Trees|
|8. Transplanting||Early spring just before new growth begins|
|9. Fireblight & pruning||Prune now to remove cankered stems and reduce infection|
|10. Sphaeropsis tip blight||Fungicide applications begin in April|
|11. Fruit tree spray schedules||See Missouri Fruit Spray Schedule for Homeowners|
|12. Reducing crabapple fruit set||Apply products when tree is in bloom; follow directions|
|13. Pruning shrubs to repair damage||When pruning, use heading back & thinning out cuts|
|14. Plum pockets & peach leaf curl||Dormant sprays must be applied before leaves begin to expand|
|15. Pine wilt tree removal||Remove and destroy dead pines affected by pine wilt before April 30.|
|16. Dividing perennials||Divide summer and fall bloomers just before new growth|
|17. Cutting herbaceous perennials||Hold off on Caryopteris/Buddleia to determine winter injury|
|18. Rabbit damage to new growth||Protect new growth from rabbit nibbling, i.e. Asiatic lilies|
|19. Fungicide applications||Select for disease resistance; be prepared to control|
|20. Food Safety Begins on the Farm||Good Ag Practices (GAPs) Network from Cornell University|
|21. English to Spanish Guides||English to Spanish language guides available for the commercial horticulture industry|
|22. Garden Center Update DVDs available||Horticulture DVDs and videos are great educational tools for nurseries & garden centers|
1. Gray snow mold has affected a large number of lawns in the state due to extended snow cover. The main symptom is circular patches of tan turf, sometimes with orange/brown margins. Do not apply fungicides for gray snow mold at this time. Focus on turgrass recovery. Disturbing (raking, verticutting) the matted turf and a light application (<0.25 lb/M) of quick release nitrogen will help turf recover as temperatures rise. If there is a chance overseeding to aid recovery is needed, avoid preemergence herbicide applications to these areas.
Snow Mold, University of Nebraska- Lincoln Extension
2. Ice damage/oxygen deprivation- An area of turf may be slow to resume growth due to ice damage and/or gray snow mold. If a frozen layer of ice developed beneath snow, turfgrass may have been smothered due to oxygen exchange problems. If damage is seen this spring, repair with overseeding as needed and use good turf management practices to aid turf recovery.
4. Wait for soil warming to seed or overseed turfgrass. Sustained temperatures of 50°F are needed for good seed germination and active root growth. April 1 to April 30 is the typical spring period for overseeding cool season turfgrasses.
5. Earthworm (nightcrawler) activity in lawns is being reported in eastern Nebraska. The bumpiness associated with earthworms is undesirable. There are no pesticides labeled for control of earthworms. Best management practices that maintain a dense turf can make earthworms casting less noticeable. Core aerifying, power raking and verticutting are mechanical processes that will break down some of the bumps in a lawn. Heavy rollers are not recommended due to soil compaction issues.
Earthworms in Lawns, Iowa State University Extension
6. Home soil sampling and soil labs- Soil tests are often recommended. The University of Nebraska-Lincoln no longer provides soil testing. This has led to an increase in questions regarding the use of home soil test kits. As a general rule, soil testing through a Soils Lab will provide more precise numbers, an increased amount of information, and are relatively inexpensive. Home soil tests most likely provide general ranges. For example, they may determine if a soil is acid or basic; but not what the exact pH is. For home soil testing, information needed from a test includes texture, organic matter content, pH, buffer pH, phosphorous (P) and potassium (K). Most home soil testing kits will not provide all of this information. Also, due to infrequent use of home soil test kits, reagents used in testing may become contaminated or lose effectiveness over time. For information on Soil Labs in Nebraska, contact your local Extension office. A list of labs is also available at the end of the following NebGuide.
Sampling Manures, University of Nebraska- Lincoln Extension
7. Prairie and Meadow Voles scarred lawns by constructing surface runways (one to two inches wide) and clipping grass very close to the roots. Numerous runways appeared after the snow melted. Small holes may lead to underground runways or nesting areas. Vole damage to lawns usually repairs itself during spring growth and is not permanent. Voles are small, mouse-like rodents that exist throughout Nebraska. Their short tails (about 1 inch long), stocky build and small eyes distinguish them from true mice.
Controlling Vole Damage, University of Nebraska- Lincoln Extension
8. Transplanting of trees and shrubs may be done as soon as soil can be worked; ideally before new growth begins. When planting or transplanting trees and shrubs, avoid common planting mistakes such as too narrow of a planting hole, planting too deep and improper mulching, which can lead to plant death or a less vigorous tree/shrub throughout the plants lifetime, and increased disease and insect problems.
Avoiding Top 10 Planting Mistakes, Nebraska Forest Service
9. Fire blight is a bacterial disease affecting apple, crabapple, pear, hawthorne and related species. The bacteria commonly live over winter in branch cankers. It is usually spread from cankers by insects and wind-blown rain. Careless pruning may also spread bacteria. Careful pruning of diseased branches during the dormant season and following petal drop can help reduce infections. Pruned branches need to be removed from the area. Cut infected branches at least 8 to 12 inches below visible injury or canker. Ideally, an infected shoot or branch should be removed at the point it attaches to another branch, without damaging the branch collar or leaving a branch stub. Avoid spreading bacteria during pruning by dipping or spraying pruning tools before each cut with a 10 percent solution of bleach (one part bleach to nine parts water). Dry and oil tools after use to prevent rust.
Fire Blight, University of Missouri Extension
10. Sphaeropsis Tip Blight has been killing large branches in pine trees. Cool, wet weather promotes infection. Common symptoms are browning and death of branch tips, death of branches or entire trees, and black fungal structures on the base of cones. In eastern Nebraska, fungicide applications are applied during the third week in April and a second application the first week of May.
Sphaeropsis Tip, University of Nebraska- Lincoln Extension
11. Fruit Trees/Small Fruits are susceptible to a number of disease and insect pests. Often, selection and planting of resistant cultivars will reduce the need for pesticides. When needed, timing of pesticide applications is critical to effectively controlling targeted pests. For recommended fruit spray schedules see the following publication.
Fruit Spray Schedules for Homeowners, University of Missouri Extension
12. Spraying to reduce crabapple fruit set is possible, but tricky. For owners of a crabapple that annually creates a mess by dropping fruit, there are products on the market. Most are hormonal or insecticidal and cause fruit to abort before they are fully formed. Timing of application is critical and usually done during or immediately after flowering. With insecticidal products, pollinating insects such as bees are harmed. A repeat application may be needed. Be sure to read and follow label directions closely. Homeowners may also consider replacing older crabapples with newer cultivars to stop the annual mess. Newer cultivars typically have smaller fruit that persists long into winter so fruit shrivels or is eaten by birds, eliminating the mess. Many newer cultivars also have increased resistance to common diseases.
Crabapples for the Home Landscape, Morton Arboretum
13. Shrub pruning to repair rabbit and snow damage is needed now that snow as melted. Remove broken branches as soon as possible. On spring bloomers, wait until after blooming to do majority of pruning. The two types of pruning cuts used on shrubs are heading back and thinning out cuts. It is important to use both types to avoid shrubs becoming too tall and/or a tangled mass of stems. With heading back cuts, a branch is cut back to a healthy bud to shorten it. A thinning cut removes a stem to the ground or back to a main branch. If only heading back cuts are made, this often results in much succulent growth near the top of the shrub which shades lower stems, causing them to become leggy and bare of foliage.
Pruning Ornamental Shrubs, University of Missouri Extension
14. Plum pockets and peach leaf curl are caused by Taphrina fungus. Dormant sprays of fungicides are effective controls. At this time of year, fungicides need to be applied in late winter before buds begin to swell; and when temperatures are above 40° F. The diseases cannot be controlled once leaves have started to expand. Use the fungicides ferbam, clorothalonil (Daconil), Bordeaux or liquid lime-sulfur. Do not add oil to lime-sulfur or spray oil treatments for three weeks after application of lime-sulfur. Lime-sulfur should not be applied to trees when temperatures are below 45 or above 80°F. Follow recommended label rates for all commercial fungicides.
Peach Leaf Curl and Plum Pockets, Kansas State University Extension
15. Remove and destroy dead pine trees by April 30 to slow the spread of pine wilt, a disease caused by a microscopic organism called the pinewood nematode. The main host tree for pine wilt is Scotch pine, but Austrian, Jack, Mugo and Red pine can also be infected.
Nematodes are spread by pine sawyer beetles (long horned beetles) which can carry thousands of nematodes in their breathing holes when they fly to pines to feed. Beetle emergence begins in May; hence the need to destroy infected trees by April 30. Trees infected with pine wilt cannot be saved. After cutting, the wood can be burned, buried or chipped. Do not save the wood from these trees firewood.
Pine Wilt, University of Nebraska- LIncoln Extension
16. Dividing Perennials is an important practice to maintaining vigorous plants with optimum blooming. As a rule, divide summer and fall blooming perennials during spring, beginning just before new growth begins.
Divide and Conquer, eXtension.org
17. Cutting back perennials and ornamental grasses in spring, before new growth begins, is important to cleaning up the landscape, making room for new growth, and a sanitation practice that may help reduce pests. Last year's growth is dead and needs to be removed. It is fine to delay this practice until just before new growth begins as old growth does provide some protection from spring freezes. Delay pruning on slow to begin growth plants, such as Caryopteris and Buddleia, to better assess the amount of winter injury.
19. Vegetable disease control in the garden may be an even higher priority this season given the increase in disease promoted by last year's cooler and wetter than average weather. Select vegetable varieties with disease resistance. Plant at the correct spacing for good air flow, avoid overhead irrigation, and use mulch to reduce soil splash. Monitor plants closely and begin fungicide applications at the first sign of disease infection on foliage. The fungicide barrier must be maintained on leaf surfaces to prevent infection. Follow label directions.
Selected Vegetable Cultivars for Nebraska, University of Nebraska- Lincoln Extension
20. Food Safety Begins on the Farm- Good Agricultural Practices for Fresh Produce Growers. Commercial vegetable and fruit growers should become familiar with Good Agricultural Practices (GAP) procedures and practices to do their part reduce potential microbial contamination and enhance food safety. Educational materials on principles involved and how to develop individual farm GAP procedures are available in English, Spanish, and other languages through the national GAPS Network for Education and Training.
Good Agricultural Practices for Fresh Produce Growers
- Guide for Communication for the Green Industry- Phrases for Hiring & Firing, Meeting and Greeting, Common Phrases, Numbers, Colors, Days, Months, Dates & Times, Telling Time and more.
- Guide for Commnication for Landscaping & Grounds Keeping- Phrases for Installation, Maintenance, Weather, Seasons, Terms, Locations, Actions, Quantities and more.
- Guide for Communication for Golf & Pond Maintenance- Phrases for Golf Course Operations, Ornamentals, Pond Maintenance, Soil Types, Plants Types, Bugs, Tools and Driving a Vehicle.
Cost- $8.99 each or all three for $25.00. Bulk discounts available.
22. Garden Center Update DVDs available- With video narration and content provided by John Fech, UNL Extension Educator, these video/DVDs are great training resources for nursery & garden center employees.
- Containers Big & Small- Learn: How Containers are Used in the Landscape | How to Select Containers for Special Uses | How to Select and Place Plants in Containers | Appropriate Use of Containers in Public Places | Who Buys Containers and Why (31 min.)
- Plants for Problem Places- Learn how to: Analyze a Landscape for Potential Problems | Solve Design Problems with Perennials & Annuals | Use Groundcovers & Vines Effectively | Anticipate Insect & Disease Problems (30 min.)
- Annuals & Perennials- Learn how to: Design a Flower Bed | Use Proper Cultural Practices | Use Containers Effectively | Divide & Multiple Perennials (53 min.)
- Lawn Establishment & Renovation: Off to a Good Start- Learn how to: Assess a turfgrass site before renovation | Eliminate the problems of turfgrass establishment | Prepare turfgrass sites for renovation | Establish a turfgrass from seed (30 min.)
- Making Every Drop Count: Irrigation Efficiency- Learn how to: Schedule irrigation | Measure water distribution | Select irrigation heads | Reduce runoff & water wasted (30 min.)
- Using Small Trees in the Landscape- Learn how to: Select small trees | Use small trees in the landscape | Use small trees for special purposes | Develop new cultivars (30 min.)
- Seasonal Rose Care: Essential Maintenance Practices- Learn how to: Plant & transplant roses | Prune roses for health & bloom | Detect disease & insect problems | Protect roses over winter (30 min.)
- Making Every Drop Count: Irrigation Efficiency- Learn how to: Schedule irrigation | Measure water distribution | Select irrigation heads | Reduce runoff and water wasted (30 min.)