Hort Update for the week of 3/10/08
1. Prairie and Meadow Voles scar lawns by constructing surface runways (one to two inches wide) and clipping grass very close to the roots. Runways are most visible after snow melts. Small holes 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. Vole damage is costliest when they eat the inner green bark layer of trees and shrubs during winter. This gnawing can severely damage or kill young trees and shrubs. In gardens, voles can clip off young plants and dig up seeds. They also eat leaves, shoots, roots, tubers and seeds of most grasses, forbs and broadleaf flowering plants.
Internet Resource: http://www.ianrpubs.unl.edu/sendIt/g887.pdf
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2. Gray Snow Mold appears as grayish, roughly circular patches in infected lawns, especially where snow cover persisted for a period of time. The fungal mycelium may appear as a dry mat or papery crust. Repair snow mold damage by raking in early spring to disrupt the matted areas and lightly fertilize to encourage new growth.
Fungicides are not recommended for home lawns except in extreme situations. Though symptoms look dramatic, the turf will recover eventually. Use cultural practices described above. If needed, fungicides can be used preventively in November and repeated during mid-winter thaws, especially for high-value turf or areas prone to problems with snow mold.
Snow Molds on Turfgrass: http://www.plantpath.k-state.edu/DesktopDefault.aspx?tabid=632
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3. Emerald Ash Borer is a borer that is killing thousands of green and white ash in eastern states and has reached as far west as Illinois. EAB is not known to be in Nebraska as of yet, but is expected to reach Nebraska at some time in the near or distant future.
For this reason, UNL Extension and the Nebraska Forest Service have stopped recommending the planting of any green or white ash trees in Nebraska. A common way for this borer to move into a state is through the transportation of firewood across state lines. It is important for people to know this and to not transport ash firewood across state lines. It is important to remain up to date on Emerald Ash Borer.
Emerald Ash Borer, http://www.emeraldashborer.info
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4. Pine Wilt mainly infects Scotch pine trees. Scotch pine that have recently died or are dieing fairly rapidly in the tree crown may have pine wilt. If this is suspected, these trees need to be removed by April 30 to slow the spread of this disease.
Pine wilt is a fatal disease of Scotch pine, which should no longer be planted in Nebraska. The disease has already killed thousands of Scotch pines in southeastern Nebraska and has been found mostly from Grand Island east, but it is also found in western Nebraska.
Pine wilt is caused by a microscopic organism called a pinewood nematode, which is spread by pine sawyer beetles which can carry thousands of nematodes on their bodies when they fly to other trees to feed. Trees infected with pine wilt cannot be saved They must be cut down and burned, buried or chipped before beetles emerge from the wood in May. Do not save the wood from these trees firewood.
Nebraska Forest Service Pine Wilt, http://www.nfs.unl.edu/documents/foresthealth/pinewilt.pdf
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5. Bagworms. Tightly woven brown bags 1.5 to 2.5 inches long and covered with brown needles. Most often found on evergreens, but also on deciduous trees such as crabapple. The bags contain overwintering eggs. Removing and destroying the bags between now and late May will help reduce populations. The time to apply insecticides is just after egg hatch in early June.
Insects on Evergreen Trees in Nebraska, http://www.nfs.unl.edu/ForestHealth/fh-insect-evergreen.asp
Controlling Bagworm in the Landscape, http://extensionhorticulture.unl.edu/Current/Bagworm.shtml
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6. Dormant Oil Sprays for Insects/Mites: March is the month to apply dormant oil sprays to fruit, nut and ornamental trees to kill insects and mites overwintering in cracks and crevices on trunks and branches. Temperatures need to be above 40 degrees Fahrenheit when applying dormant oils, which are commonly used to control pests such as aphids, scales, spider mites, insect eggs and some hibernating caterpillars. A few dormant oils are labeled for use on white flies, mealybugs and lacebugs. Dormant oils kill by suffocating insects and mites. Dormant oils are most effective if applied as late in winter as possible, but before spring growth begins. At this time, insects are weakened and easier to kill. Also, dormant oils can damage tender plant tissue and should not be used once flowers or leaves begin to grow. Follow label directions when using any pesticide.
Dormant Sprays for Taphrina Leaf Curl: Peach leaf curl and plum pocket can be controlled with a single application of an appropriate fungicide. The timing of the fungicide spray is extremely important and should be applied as a dormant spray, either in the fall after leaf drop or in late winter before buds begin to swell. These diseases cannot be controlled once the leaves have started to expand. Some of the fungicides registered for control of peach leaf curl and plum pocket include liquid lime-sulfur, ferbam, chlorothalonil , Bordeaux mixture and other copper chemicals. 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, http://www.oznet.ksu.edu/dp_hfrr/extensn/problems/pchlfcrl.htm
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7. Delay Mulch Removal on plants such as strawberries, roses, or Chrysanthemums that have been protected with a winter mulch. Early removal may cause new growth to begin too early and be susceptible to cold temperature damage. Ideally, delay mulch removal as long as possible but do remove it before new growth begins beneath the mulch. If warm temperatures cause new growth to begin early, rake the mulch to the side of the plant so it can be raked over the plants if freezing temperatures are forecast.
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8. Pruning Tips:
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9. Red Clover Mites. These small mites are often found on west and south facing windows and walls in the spring. These mites overwintered under siding and window frames. When temperatures warm up the mites become active. A wet washcloth or paper towel will control the pests on windows and walls. These nuisance mites do no damage to people, pets, or the house structure. Insecticides are not recommended for use indoors. An outdoor perimeter spray applied in the fall will help keep the mites from entering the home.
Clover Mite, http://ohioline.osu.edu/hyg-fact/2000/2095.html
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10. eXtension is a new national website offering research based information from Extension on a variety of topics referred to as "Communities of Practice." The current Communities of Practice include Gardens, Lawns and Landscapes; Wildlife Damage Management; and Beef, Cotton, Dairy, Disaster Education, Diversity, Entrepreneurship, Family Caregiving, Fire Ants, Livestock & Poultry, Map@syst, Parenting, Personal Finance, and Youth SET for Life.
eXtension is brought to you through a unique partnership of more than 70 universities found in every state and territory throughout the United States. These land-grant universities have as their missions research, teaching, and outreach to Americans. eXtension brings the best of the best from these institutions.
For more information, visit eXtension, http://www.extension.org/
| Current Problems: | Major Symptom: |
| Lawns | |
| 1. Voles | Runways of clipped grass on lawn surfaces |
| 2. Gray snow mold | Matted, grayish patches in the lawn |
| Trees & Shrubs | |
| 3. Emerald ash borer | NOT known to be in Nebraska yet. Informational website. |
| 4. Pine wilt | Dead Scotch Pine trees or rapid crown dieback - remove by April 30 |
| 5. Bagworms | 1.5-2.5" long brown bags attached to trees. |
| To Do's for March | |
| 6. Apply dormant sprays | For overwintering insects & Taphrina leaf curl |
| 7. Delay mulch removal | For roses, strawberries, Chrysanthemums |
| 8. Pruning | Shade trees, summer blooming shrubs, fruit trees, grapes |
| Miscellaneous | |
| 9. Clover mites | Red specks (mites) crawling on windows and furniture |
| 10. eXtension | New national Extension website |
1. Prairie and Meadow Voles scar lawns by constructing surface runways (one to two inches wide) and clipping grass very close to the roots. Runways are most visible after snow melts. Small holes 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. Vole damage is costliest when they eat the inner green bark layer of trees and shrubs during winter. This gnawing can severely damage or kill young trees and shrubs. In gardens, voles can clip off young plants and dig up seeds. They also eat leaves, shoots, roots, tubers and seeds of most grasses, forbs and broadleaf flowering plants.
Internet Resource: http://www.ianrpubs.unl.edu/sendIt/g887.pdf
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2. Gray Snow Mold appears as grayish, roughly circular patches in infected lawns, especially where snow cover persisted for a period of time. The fungal mycelium may appear as a dry mat or papery crust. Repair snow mold damage by raking in early spring to disrupt the matted areas and lightly fertilize to encourage new growth.
Fungicides are not recommended for home lawns except in extreme situations. Though symptoms look dramatic, the turf will recover eventually. Use cultural practices described above. If needed, fungicides can be used preventively in November and repeated during mid-winter thaws, especially for high-value turf or areas prone to problems with snow mold.
Snow Molds on Turfgrass: http://www.plantpath.k-state.edu/DesktopDefault.aspx?tabid=632
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3. Emerald Ash Borer is a borer that is killing thousands of green and white ash in eastern states and has reached as far west as Illinois. EAB is not known to be in Nebraska as of yet, but is expected to reach Nebraska at some time in the near or distant future.
For this reason, UNL Extension and the Nebraska Forest Service have stopped recommending the planting of any green or white ash trees in Nebraska. A common way for this borer to move into a state is through the transportation of firewood across state lines. It is important for people to know this and to not transport ash firewood across state lines. It is important to remain up to date on Emerald Ash Borer.
Emerald Ash Borer, http://www.emeraldashborer.info
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4. Pine Wilt mainly infects Scotch pine trees. Scotch pine that have recently died or are dieing fairly rapidly in the tree crown may have pine wilt. If this is suspected, these trees need to be removed by April 30 to slow the spread of this disease.
Pine wilt is a fatal disease of Scotch pine, which should no longer be planted in Nebraska. The disease has already killed thousands of Scotch pines in southeastern Nebraska and has been found mostly from Grand Island east, but it is also found in western Nebraska.
Pine wilt is caused by a microscopic organism called a pinewood nematode, which is spread by pine sawyer beetles which can carry thousands of nematodes on their bodies when they fly to other trees to feed. Trees infected with pine wilt cannot be saved They must be cut down and burned, buried or chipped before beetles emerge from the wood in May. Do not save the wood from these trees firewood.
Nebraska Forest Service Pine Wilt, http://www.nfs.unl.edu/documents/foresthealth/pinewilt.pdf
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5. Bagworms. Tightly woven brown bags 1.5 to 2.5 inches long and covered with brown needles. Most often found on evergreens, but also on deciduous trees such as crabapple. The bags contain overwintering eggs. Removing and destroying the bags between now and late May will help reduce populations. The time to apply insecticides is just after egg hatch in early June.
Insects on Evergreen Trees in Nebraska, http://www.nfs.unl.edu/ForestHealth/fh-insect-evergreen.asp
Controlling Bagworm in the Landscape, http://extensionhorticulture.unl.edu/Current/Bagworm.shtml
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6. Dormant Oil Sprays for Insects/Mites: March is the month to apply dormant oil sprays to fruit, nut and ornamental trees to kill insects and mites overwintering in cracks and crevices on trunks and branches. Temperatures need to be above 40 degrees Fahrenheit when applying dormant oils, which are commonly used to control pests such as aphids, scales, spider mites, insect eggs and some hibernating caterpillars. A few dormant oils are labeled for use on white flies, mealybugs and lacebugs. Dormant oils kill by suffocating insects and mites. Dormant oils are most effective if applied as late in winter as possible, but before spring growth begins. At this time, insects are weakened and easier to kill. Also, dormant oils can damage tender plant tissue and should not be used once flowers or leaves begin to grow. Follow label directions when using any pesticide.
Dormant Sprays for Taphrina Leaf Curl: Peach leaf curl and plum pocket can be controlled with a single application of an appropriate fungicide. The timing of the fungicide spray is extremely important and should be applied as a dormant spray, either in the fall after leaf drop or in late winter before buds begin to swell. These diseases cannot be controlled once the leaves have started to expand. Some of the fungicides registered for control of peach leaf curl and plum pocket include liquid lime-sulfur, ferbam, chlorothalonil , Bordeaux mixture and other copper chemicals. 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, http://www.oznet.ksu.edu/dp_hfrr/extensn/problems/pchlfcrl.htm
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7. Delay Mulch Removal on plants such as strawberries, roses, or Chrysanthemums that have been protected with a winter mulch. Early removal may cause new growth to begin too early and be susceptible to cold temperature damage. Ideally, delay mulch removal as long as possible but do remove it before new growth begins beneath the mulch. If warm temperatures cause new growth to begin early, rake the mulch to the side of the plant so it can be raked over the plants if freezing temperatures are forecast.
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8. Pruning Tips:
- February and March are key pruning times for many plants.
- Only prune if pruning is needed. Do not prune just for the sake of pruning.
- Make proper pruning cuts and use sharp pruning tools.
- Do not use pruning paints or wound dressings on pruning wounds.
- When pruning fruit trees, understand what age wood the different species bear fruit on.
- For the best time to prune different plants, see the “When to Prune Common Landscape Plants” chart at the following web site, http://www.platte.unl.edu/yardandgarden
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9. Red Clover Mites. These small mites are often found on west and south facing windows and walls in the spring. These mites overwintered under siding and window frames. When temperatures warm up the mites become active. A wet washcloth or paper towel will control the pests on windows and walls. These nuisance mites do no damage to people, pets, or the house structure. Insecticides are not recommended for use indoors. An outdoor perimeter spray applied in the fall will help keep the mites from entering the home.
Clover Mite, http://ohioline.osu.edu/hyg-fact/2000/2095.html
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
10. eXtension is a new national website offering research based information from Extension on a variety of topics referred to as "Communities of Practice." The current Communities of Practice include Gardens, Lawns and Landscapes; Wildlife Damage Management; and Beef, Cotton, Dairy, Disaster Education, Diversity, Entrepreneurship, Family Caregiving, Fire Ants, Livestock & Poultry, Map@syst, Parenting, Personal Finance, and Youth SET for Life.
eXtension is brought to you through a unique partnership of more than 70 universities found in every state and territory throughout the United States. These land-grant universities have as their missions research, teaching, and outreach to Americans. eXtension brings the best of the best from these institutions.
For more information, visit eXtension, http://www.extension.org/
