Hort Update for the week of 11/10/08
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1. Temperatures & Herbicide Application- Fall is the ideal time to control perennial weeds like dandelion, clover and creeping charlie (ground ivy). Care should be taken as temperatures drop, to apply systemic herbicides when the ambient temperature is sustained above 50-60 F for several hours after spraying. This insures movement of the herbicides from the leaves to below ground storage organs such as rhizomes, roots, corms etc. Do not spray systemic herbicides when the ground is frozen even if ambient temperatures are elevated.
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2. Kentucky Bluegrass Stem Rust has been prevalent in western Nebraska. An obvious symptom is rust colored “powder” (fungal spores) on grass blades, shoes and lawn mower. Heavily infected turfgrass may show yellowing of grass blades. Stem Rust typically develops on lawns with slow growth. Fall lawn care, including fertilization and correct irrigation, along with cooler fall weather promotes turfgrass growth and rust dissipates. Stem rust is often a problem on compacted soils; hence core aerification is effective in reducing rust disease. Fungicide controls are rarely suggested for home lawns.
Note for Sports Turf- If stem rust occurs on sports fields, the fungal spores can cause problems for allergy/asthma sufferers. Control of stem rust is recommended on sports turfs using a combination of turf management and timely fungicide applications.
Rust Turns Lawns Orange, http://www.urbanext.uiuc.edu/turf/rustlawn.html
Rust on Sports Turf, http://hcs.osu.edu/sportsturf/notes/detail.lasso?id=1094
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3. Mowing Height recommendations have changed. Historically it was recommended to mow turfgrass shorter in autumn. The alternative recommendation is to maintain the same height all season and through winter. This promotes rooting and stress tolerance. Mow Kentucky Bluegrass at 2.5 to 3.0 inches and tall fescue at 3.0 to 3.5 inches all season and leave it at this height for winter. Continue to mow as long as turfgrass is growing. Do not allow it to go into winter too tall or matting and suffocation may occur; as well as an increased incidence of snow mold disease.
Kentucky Bluegrass Lawn Calendar Nebguide, http://www.ianrpubs.unl.edu/sendIt/g517.pdf
Tall Fescue Lawn Calendar Nebguide, http://www.ianrpubs.unl.edu/sendIt/g558.html
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4. Fall Irrigation of turf, in the absence of rainfall, is important for maintaining a moist soil to support root and rhizome growth which increases during fall. Turfgrass soils should remain moist, not saturated, well into fall. Irrigation systems must also be protected from freeze damage by draining them. Information on proper drainage procedures for home lawn irrigation systems with back flow preventers can be found on page 23 of the Integrated Turfgrass Management for the Northern Great Plains E.C.97-1557. A copy of this Extension circular is available at most UNL Extension offices.
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5. Cytospora Canker is most common on Spruce trees. This disease causes branches near the base of trees to die or trees to die from the top down. A bluish-white resin often oozes from branch or trunk cankers. There are no fungicide controls. Prune and destroy dead and dying branches during winter. The fungus often spreads during spring rains. Disinfect all pruning tools such as knives and saws by wiping them with rubbing alcohol. Avoid stress by spacing trees correctly, then mulching and watering correctly. Avoid wounds. Black Hills Spruce is less susceptible to this disease.
Diseases of Evergreen Trees, http://www.nfs.unl.edu/documents/foresthealth/diseasesevergreen.pdf
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6. Winter Animal Damage- Barriers of hardware cloth placed around young trees and shrubs is the best means of protection from rabbit and vole damage. Make sure the barriers extend well above the usual snow line. Various taste repellants, such as Thiram or Millers Hot Sauce, can be effective in reducing deer and rabbit damage as long as animals have other food sources to turn to. Scent repellants, such as bags of human hair or bar soaps on a rope, have been shown to be effective in some situations.
eXtension Deer Damage Management, http://www.extension.org/pages/Deer_Damage_Management
eXtension Vole Damage Management, http://www.extension.org/pages/Vole_Damage_Management
eXtension Rabbit Damage Management, http://www.extension.org/pages/Cottontail_Rabbit_Damage_Management
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7. Leaves are an important source of organic matter. They also contribute to water pollution. When leaves, and other plant debris, decompose phosphorous and nitrogen is released. To reduce the pollutant load on surface water, reduce the amount of tree leaves in the path of stormwater (rainfall and snow melt). Rake and compost leaves, use them as mulch, or take them to a local plant waste recycling center. Do not sweep or blow leaves into the street where stormwater from rainfall and snow melt carries them to storm drains and then directly to receiving waters (lakes, rivers, ponds, and streams). Do not dump them on streambanks.
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8. Euonymous Scale Leaves turn yellow, then die and drop off. Undersides of leaves and stems are covered with a brown or white scale. Scale insects feed from beneath the protective scale, removing plant sap from stems and leaves. Controls are most effective when the insect is in the crawler stage, usually in May to early June and late August to early September (second generation). Monitor for the presence of crawlers by wrapping a few stems with black electrical tape with the sticky surface facing out near where scales are present. Crawlers are yellowish to orange. When in the crawler stage, control with insecticidal soaps. Systemic insecticides are also effective. Read and follow label directions for effective application. Prune and remove heavily infested branches to the ground.
Euonymous Scale, http://www.oznet.ksu.edu/dp_hfrr/extensn/problems/eonscale.htm
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9. Overwintering Tender “Bulbs”- Plants such as cannas, tuberous begonias, and gladioli are not hardy to Nebraska winters. These need to be dug and stored over winter. For success, the correct temperature and humidity levels are required for storage. Please see: Storing Bulbs and Tender Bulbs for information on storage conditions for specific bulbs/bulb-like structures.
Storing Bulbs and Tender Bulbs, http://www.extension.umn.edu/distribution/horticulture/DG1117.html
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10. Winter Protection for Roses should not be put in place until roses are fully dormant which is usually after the soil begins to freeze or night time temperatures are consistently dropping into the 20 degree F. range sometime in November. Winter protection protects plants against wide soil temperature fluctuations and temperature extremes . On hybrid tea, floribunda and other tender roses, about 8 inches of soil can be mounded around the base in early November to protect the graft. About mid-November, put your cover in place. Encircling the plant with chicken wire and filling the chicken wire with coarse mulch, such as wood chips, works well.
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11. Storing apples- Under ideal storage conditions, late maturing cultivar such as Red Delicious, Northern Spy, Stayman, Winesap and Rome Beauty can be stored up to five months. Only good-quality fruit free of bruises, cuts or other damage should be stored. One bad apple can spoil the whole lot by introducing rot organisms and releasing increased levels of ethylene gas, which hastens the ripening and aging process.
Apples are best stored at 30-32 F with 90 percent relative humidity and some air circulation. Warmer temperatures will cause the apples to age faster, and low humidity can cause excessive shriveling. The most practical solution for home storage is the refrigerator.
Pack apples in perforated plastic bags to keep the humidity high yet still allow some air circulation through the holes in the bag. A cool cellar or an unheated room or outbuilding can be used as long as temperature can be kept below 40 F but above 30 F with reasonable humidity.
Storing Apples for Winter, http://www.hort.purdue.edu/ext/applestor.html
Storing Fresh Fruits & Vegetables, http://www.ianrpubs.unl.edu/sendIt/g1264.pdf
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12. Fall Sanitation and compost piles- Fall sanitation is the removal and disposal of dead or dying plant material from gardens and from beneath fruit trees to reduce overwintering pathogens and insects. Many diseases and insects also overwinter on weeds so don’t overlook cleaning up weeds as well. Plant debris can be tilled under or removed and destroyed. It can be added to compost piles. However, if the material comes from a plant which had a disease or insect problem or is a weed that has gone to seed; it is best not to add this material to compost piles. While a properly managed pile may reach temperatures hot enough to kill most pathogens and weed seeds, many piles are not managed to reach this temperature.
Garden Compost, http://www.ianrpubs.unl.edu/sendIt/g810.pdf
| Current Problems: | Major Symptom: |
| Lawns | |
| 1. Temperatures for herbicides | Daytime air temperatures above 50 degrees F needed |
| 2. Kentucky bluegrass stem rust (western Nebraska) | Yellowing turfgrass. Rust colored “powder” on shoes, mowers |
| 3. Winter lawn height | Mow Kentucky bluegrass at 2.5-3.0” and Tall Fescue at 3.0-3.5” for winter |
| 4. Fall irrigation | Keep soils moist, not saturated. Protect irrigation systems from freezing |
| Trees/Shrubs | |
| 5. Spruce Cytospora canker | Hail promotes. branch or tree dieback. Bluish-white resin present on bark. |
| 6. Winter animal damage | Protect trees from rabbit, vole and deer feeding during winter |
| 7. Recycling leaf debris | Keep out of the path of rain water to help protect water resources |
| Landscape Ornamentals | |
| 8. Euonymous scale | Browning of leaves; twigs covered with scales |
| 9. Overwintering tender bulbs | Dig and store Cannas, Dahlias, Gladioli and others |
| 10. Rose winter protection | Wait until mid November to apply winter protection |
| Vegetables/Fruits | |
| 11. Storing apples | Ideal storage is humid and 30 to 32 Degree F. temperatures |
| 12. Fall sanitation & composting | Important to reducing overwintering pests |
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1. Temperatures & Herbicide Application- Fall is the ideal time to control perennial weeds like dandelion, clover and creeping charlie (ground ivy). Care should be taken as temperatures drop, to apply systemic herbicides when the ambient temperature is sustained above 50-60 F for several hours after spraying. This insures movement of the herbicides from the leaves to below ground storage organs such as rhizomes, roots, corms etc. Do not spray systemic herbicides when the ground is frozen even if ambient temperatures are elevated.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
2. Kentucky Bluegrass Stem Rust has been prevalent in western Nebraska. An obvious symptom is rust colored “powder” (fungal spores) on grass blades, shoes and lawn mower. Heavily infected turfgrass may show yellowing of grass blades. Stem Rust typically develops on lawns with slow growth. Fall lawn care, including fertilization and correct irrigation, along with cooler fall weather promotes turfgrass growth and rust dissipates. Stem rust is often a problem on compacted soils; hence core aerification is effective in reducing rust disease. Fungicide controls are rarely suggested for home lawns.
Note for Sports Turf- If stem rust occurs on sports fields, the fungal spores can cause problems for allergy/asthma sufferers. Control of stem rust is recommended on sports turfs using a combination of turf management and timely fungicide applications.
Rust Turns Lawns Orange, http://www.urbanext.uiuc.edu/turf/rustlawn.html
Rust on Sports Turf, http://hcs.osu.edu/sportsturf/notes/detail.lasso?id=1094
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3. Mowing Height recommendations have changed. Historically it was recommended to mow turfgrass shorter in autumn. The alternative recommendation is to maintain the same height all season and through winter. This promotes rooting and stress tolerance. Mow Kentucky Bluegrass at 2.5 to 3.0 inches and tall fescue at 3.0 to 3.5 inches all season and leave it at this height for winter. Continue to mow as long as turfgrass is growing. Do not allow it to go into winter too tall or matting and suffocation may occur; as well as an increased incidence of snow mold disease.
Kentucky Bluegrass Lawn Calendar Nebguide, http://www.ianrpubs.unl.edu/sendIt/g517.pdf
Tall Fescue Lawn Calendar Nebguide, http://www.ianrpubs.unl.edu/sendIt/g558.html
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4. Fall Irrigation of turf, in the absence of rainfall, is important for maintaining a moist soil to support root and rhizome growth which increases during fall. Turfgrass soils should remain moist, not saturated, well into fall. Irrigation systems must also be protected from freeze damage by draining them. Information on proper drainage procedures for home lawn irrigation systems with back flow preventers can be found on page 23 of the Integrated Turfgrass Management for the Northern Great Plains E.C.97-1557. A copy of this Extension circular is available at most UNL Extension offices.
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5. Cytospora Canker is most common on Spruce trees. This disease causes branches near the base of trees to die or trees to die from the top down. A bluish-white resin often oozes from branch or trunk cankers. There are no fungicide controls. Prune and destroy dead and dying branches during winter. The fungus often spreads during spring rains. Disinfect all pruning tools such as knives and saws by wiping them with rubbing alcohol. Avoid stress by spacing trees correctly, then mulching and watering correctly. Avoid wounds. Black Hills Spruce is less susceptible to this disease.
Diseases of Evergreen Trees, http://www.nfs.unl.edu/documents/foresthealth/diseasesevergreen.pdf
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6. Winter Animal Damage- Barriers of hardware cloth placed around young trees and shrubs is the best means of protection from rabbit and vole damage. Make sure the barriers extend well above the usual snow line. Various taste repellants, such as Thiram or Millers Hot Sauce, can be effective in reducing deer and rabbit damage as long as animals have other food sources to turn to. Scent repellants, such as bags of human hair or bar soaps on a rope, have been shown to be effective in some situations.
eXtension Deer Damage Management, http://www.extension.org/pages/Deer_Damage_Management
eXtension Vole Damage Management, http://www.extension.org/pages/Vole_Damage_Management
eXtension Rabbit Damage Management, http://www.extension.org/pages/Cottontail_Rabbit_Damage_Management
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7. Leaves are an important source of organic matter. They also contribute to water pollution. When leaves, and other plant debris, decompose phosphorous and nitrogen is released. To reduce the pollutant load on surface water, reduce the amount of tree leaves in the path of stormwater (rainfall and snow melt). Rake and compost leaves, use them as mulch, or take them to a local plant waste recycling center. Do not sweep or blow leaves into the street where stormwater from rainfall and snow melt carries them to storm drains and then directly to receiving waters (lakes, rivers, ponds, and streams). Do not dump them on streambanks.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
8. Euonymous Scale Leaves turn yellow, then die and drop off. Undersides of leaves and stems are covered with a brown or white scale. Scale insects feed from beneath the protective scale, removing plant sap from stems and leaves. Controls are most effective when the insect is in the crawler stage, usually in May to early June and late August to early September (second generation). Monitor for the presence of crawlers by wrapping a few stems with black electrical tape with the sticky surface facing out near where scales are present. Crawlers are yellowish to orange. When in the crawler stage, control with insecticidal soaps. Systemic insecticides are also effective. Read and follow label directions for effective application. Prune and remove heavily infested branches to the ground.
Euonymous Scale, http://www.oznet.ksu.edu/dp_hfrr/extensn/problems/eonscale.htm
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9. Overwintering Tender “Bulbs”- Plants such as cannas, tuberous begonias, and gladioli are not hardy to Nebraska winters. These need to be dug and stored over winter. For success, the correct temperature and humidity levels are required for storage. Please see: Storing Bulbs and Tender Bulbs for information on storage conditions for specific bulbs/bulb-like structures.
Storing Bulbs and Tender Bulbs, http://www.extension.umn.edu/distribution/horticulture/DG1117.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
10. Winter Protection for Roses should not be put in place until roses are fully dormant which is usually after the soil begins to freeze or night time temperatures are consistently dropping into the 20 degree F. range sometime in November. Winter protection protects plants against wide soil temperature fluctuations and temperature extremes . On hybrid tea, floribunda and other tender roses, about 8 inches of soil can be mounded around the base in early November to protect the graft. About mid-November, put your cover in place. Encircling the plant with chicken wire and filling the chicken wire with coarse mulch, such as wood chips, works well.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
11. Storing apples- Under ideal storage conditions, late maturing cultivar such as Red Delicious, Northern Spy, Stayman, Winesap and Rome Beauty can be stored up to five months. Only good-quality fruit free of bruises, cuts or other damage should be stored. One bad apple can spoil the whole lot by introducing rot organisms and releasing increased levels of ethylene gas, which hastens the ripening and aging process.
Apples are best stored at 30-32 F with 90 percent relative humidity and some air circulation. Warmer temperatures will cause the apples to age faster, and low humidity can cause excessive shriveling. The most practical solution for home storage is the refrigerator.
Pack apples in perforated plastic bags to keep the humidity high yet still allow some air circulation through the holes in the bag. A cool cellar or an unheated room or outbuilding can be used as long as temperature can be kept below 40 F but above 30 F with reasonable humidity.
Storing Apples for Winter, http://www.hort.purdue.edu/ext/applestor.html
Storing Fresh Fruits & Vegetables, http://www.ianrpubs.unl.edu/sendIt/g1264.pdf
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12. Fall Sanitation and compost piles- Fall sanitation is the removal and disposal of dead or dying plant material from gardens and from beneath fruit trees to reduce overwintering pathogens and insects. Many diseases and insects also overwinter on weeds so don’t overlook cleaning up weeds as well. Plant debris can be tilled under or removed and destroyed. It can be added to compost piles. However, if the material comes from a plant which had a disease or insect problem or is a weed that has gone to seed; it is best not to add this material to compost piles. While a properly managed pile may reach temperatures hot enough to kill most pathogens and weed seeds, many piles are not managed to reach this temperature.
Garden Compost, http://www.ianrpubs.unl.edu/sendIt/g810.pdf
